{"paper_id":"359db2fd-eb46-4da5-b299-8e30ff10a928","body_text":"Preparation of Ce-UiO-66-NH₂/TiO₂/PANI Composite and Photocatalytic Degradation of RhB | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Preparation of Ce-UiO-66-NH₂/TiO₂/PANI Composite and Photocatalytic Degradation of RhB Lili Li, Jiaxing Li, Yuyu Ma, Jing Shu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9454538/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The Ce-UiO-66-NH 2 material was successfully prepared by oil bath method, and TiO 2 and PANI were compounded on the basis of it, which improved the degradation efficiency of rhodamine B ( RhB ). XRD, TEM and XPS characterization confirmed that the composite material formed a core-shell structure and polyaniline was uniformly coated. The composite with 20µL aniline and CTAB surfactant showed the highest degradation efficiency, and the degradation rate of RhB reached 99.90% within 60 min under ultraviolet light irradiation. The band alignment and free radical trapping experiments show that it follows the ternary Z-type heterojunction mechanism, •O 2 − is the main active species. It provides a new idea for the design of high-performance photocatalysts and is of great significance for promoting the application of photocatalytic technology in water pollution control. Photocatalysis Ce-UiO-66-NH₂ TiO₂ PANI Type-Zheterojunction Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1. Introduction With the acceleration of the industrialization process, its negative impact on human society is also further revealed, and energy shortages and environmental problems are becoming more and more serious. Among them, water pollution is one of the most serious problems. Some wastewater produced in industrial production contains a large number of organic pollutants and heavy metal ions, including but not limited to organic dyes, phenols, chemical fertilizers, hexavalent chromium, etc., which have great harm to the environment and human beings. Taking organic dyes as an example, more than 7×10 5 tons of commercial dyes are produced every year. These dyes have stable chemical properties and are not biodegradable in water, posing a serious threat to the environment [ 1 ]. RhB is one of the most common organic dyes in the textile industry and industrial wastewater. Therefore, exploring new materials and technologies to degrade pollutants in sewage is of great significance for maintaining the ecological environment and human health, as well as further promoting the development of industry. As a special treatment process, advanced oxidation processes (AOPs) have attracted much attention since the 20 th century. Advanced oxidation processes include ozone oxidation, Fenton oxidation, photocatalysis and so on. Among them, photocatalytic degradation technology is widely used in the field of sewage treatment because of its advantages of simplicity, high efficiency, no pollution and low cost. Photocatalytic technology is based on a series of redox reactions between photocatalyst and pollutants in sewage under light conditions, and finally achieve the purpose of degrading pollutants [ 2 – 3 ]. Photocatalytic degradation technology offers advantages such as low cost, simple operation, and ecological harmlessness, making it a highly promising environmental remediation technique. Its fundamental principle involves three basic steps: (1) Generation of electron-hole pairs under ultraviolet or visible light irradiation, (2) Separation and migration of photo-generated electrons and holes, (3) Oxidation-reduction reactions. When the energy absorbed by the photocatalyst equals or exceeds its bandgap, electrons in the valence band (VB) are excited to the conduction band (CB), leaving behind positively charged active holes (h + ) in the VB. Electrons in the CB react with dissolved O₂ in water to form superoxide radicals (•O₂⁻), while h⁺ in the VB reacts with water molecules to generate hydroxyl radicals (•OH). These reactive species possess strong oxidizing capabilities, degrading organic pollutants into H₂O and CO₂ [ 4 – 5 ]. However, in single photocatalytic materials, photogenerated electron-hole pairs rapidly recombine after separation, significantly impairing photocatalytic degradation efficiency. Conventional photocatalysts typically comprise semiconductor materials such as metal oxides and sulfides, carbon-based composites, and nitrides [ 6 – 9 ]. Metal-organic frameworks (MOFs) represent a class of inorganic-organic multifunctional metal hybrid materials. They are crystalline porous coordination polymers formed by metal ions connected through coordination bonds with organic ligand frameworks. MOFs exhibit large specific surface areas, well-defined pore structures, and structural design flexibility. Consequently, they hold broad application prospects in separation, gas storage, catalysis, photocatalysis, CO₂ capture, and other fields [ 10 ]. However, many pristine MOFs suffer from poor light absorption, rapid electron-hole recombination, low charge transfer efficiency, and poor long-term cycling stability. To address these issues, common strategies include doping metal ions to alter their band structure or compositing them with semiconductor materials to form heterojunctions, thereby promoting photogenerated charge transfer and creating additional active sites [ 11 ]. Liang et al photodeposited Au, Pd and Pt noble metals on MIL-100(Fe) to decompose MO, respectively.Studies have shown that the deposited noble metal nanoparticles are beneficial to the transfer of excited photoelectrons triggered by visible light. And prolong the life of the carrier, effectively promote the photodegradation of MO [ 12 ]. Combining MOF materials with semiconductor photocatalysts can also greatly improve the photocatalytic efficiency. Semiconductor materials have excellent light capture ability and rich surface active sites. Adding semiconductors to MOFs composites can form heterojunctions. The formation of heterojunctions will adjust the band gap of the material and promote the separation and migration of photogenerated carriers, thereby improving the photocatalytic performance of the material. Liu et al.synthesized TiO 2 @MIL-100-Fe nanosheets with a sandwich structure by self-assembly method. MIL-100-Fe has a high specific surface area, which can effectively expose more active sites, effectively prevent the aggregation of TiO 2 , and improve the efficiency of photogenerated electron generation, separation and transfer. The material has excellent photocatalytic activity for methylene blue (MB), which is 45 times and 2 times that of single TiO 2 nanosheets and MIL-100-Fe, respectively [ 13 ]. Conductive polymers with π-conjugated systems such as polyaniline (PANI) have the advantages of high electron-hole pair mobility, high absorption coefficient and environmental stability. The combination with MOF materials can effectively improve the photocatalytic efficiency and make up for the lack of stability of MOF materials [ 14 ]. In order to effectively improve the photocatalytic performance of MOF materials, Ce-based NH 2 -UiO-66 materials were prepared by oil bath heating method in this experiment. The Ce-UiO-66-NH 2 /TiO 2 binary material ( UT ) was constructed by adding pre-synthesized TiO 2 powder with different mass during the synthesis process. The binary UT material was prepared by in-situ oxidation polymerization. UTPA ternary composite material was prepared by in-situ oxidation polymerization. Rhodamine B (RhB) was used as the target pollutant, and the photocatalytic degradation performance of the composite material on RhB under ultraviolet light was investigated. The effects of different surfactants and different aniline concentrations on the photocatalytic performance were studied. The mechanism of the heterojunction of the composite material was clarified by free radical trapping experiments and band alignment, and the charge transfer process in the system was clarified. The results show that the photocatalytic degradation performance of UTPA composite material is significantly improved compared with that of single material and binary UT material. 2. Experimental 2.1 Materials N, N-Dimethylformamide (DMF) was purchased from Guangdong Wenglong Chemical Reagent Co., Ltd. 2-Aminoterephthalic acid was purchased from Shandong Keyuan Biochemical Co., Ltd. Ammonium cerium nitrate, tert-butanol, and sodium dodecyl sulfate (SDS) were purchased from Shanghai McLean Biochemical Co., Ltd. Tetrabutyl titanate (TBT) and Rhodamine B (RhB) were obtained from Beijing Chemical Co., Ltd. Ammonium persulfate (APS) and disodium ethylenediaminetetraacetate (EDTA-2Na) were sourced from Tianjin Damiao Chemical Reagent Factory. L-ascorbic acid was purchased from Tianjin Kemiou Chemical Reagent Co., Ltd. Polyvinylpyrrolidone (PVP) was purchased from Shanghai Boao Biotechnology Co., Ltd. Cetyltrimethylammonium bromide (CTAB) was purchased from Tianjin Dagang Yizhong Chemical Factory. Anhydrous ethanol was purchased from Shenyang Huadong Reagent Factory. Hydrochloric acid was purchased from Shanghai Chemical Reagent Factory, and aniline was purchased from Aladdin Biotechnology Co., Ltd. The deionized water and all chemical reagents used in this experiment were used directly without further purification. 2.2 Synthesis of TiO₂ TiO₂ was synthesized via the hydrothermal method according to a previously reported procedure [ 15 ]. A mixture of 0.1 mol TBT and 34 g hydrochloric acid (38%) was prepared in a beaker, transferred to a Teflon-lined autoclave, heated at 150°C for 24 hours, and then cooled to room temperature. After the reactor cooled to room temperature, the precipitate was separated from the suspension by centrifugation. It was washed three times with alternating portions of anhydrous ethanol and water, then dried in an air oven at 60°C for 12 hours. 2.3 Synthesis of UT Dissolve 1.2 mmol of 2-aminoterephthalic acid in 8 mL of DMF, add 0.005 g of TiO₂, dissolve 1.4 mmol of ammonium cerium nitrate in 2.7 mL of deionized water, combine both solutions in a flask, seal the flask, and heat with stirring at 100°C in an oil bath for 30 min. After cooling, centrifuge the mixture. Wash the residue three times with DMF and anhydrous ethanol, respectively. Dry at 60°C for 12 h. A single NH₂-UiO-66 material was prepared without adding TiO₂. 2.4 Synthesis of UTPA Dissolve 20 µL (10 µL, 20 µL, 40 µL) of aniline in 15 mL of 1 M hydrochloric acid. Add 20 mg of surfactant (CTAB, SDS, PVP, Blank) and 0.1 g of composite material, then mix thoroughly. Dissolve 1.5 mmol APS in 15 mL 1 M hydrochloric acid. Add this solution to the aniline mixture under an ice-water bath, stirring until the mixture turns dark green. Centrifuge the dark green mixture, wash three times with alternating deionized water and anhydrous ethanol, then dry at 60°C for 12 hours to obtain the composite material. 2.5 Characterization Methods The crystalline phases of the catalyst were characterized using X-ray diffraction (XRD, D/max-2200pc X-ray diffractometer with CuKα radiation) (CuKα radiation, tube voltage 40 kV, tube current 40 mA min⁻¹, scanning speed 5°min⁻¹). Infrared spectroscopy of molecular vibrations was performed using a Fourier Transform Infrared Spectrometer (FTIR, Tensor27, Fairburn Precision Instruments (Shanghai) Co., Ltd.); Surface area analysis was conducted using an N₂ adsorption-desorption instrument (BET, NOVA2000e, Shanghai Chuangsen Instruments Co., Ltd.); (TEM, FEI Talos f200x, FEI) to examine material morphology; XPS analysis employed a Semefi250x X-ray photoelectron spectrometer; UV-1600PC UV-visible spectrophotometer measured diffuse reflectance UV-visible spectra over 200–800 nm; An electrochemical workstation equipped with a standard three-electrode system (Shanghai Chenhua Instruments Co., Ltd.) was employed to obtain transient photocurrent response spectra, electrochemical impedance spectra, and Mott-Schottky spectra. 2.6 Photocatalytic Study The light source of the photocatalytic degradation reaction uses a 250 W mercury lamp, and the light source is equipped with a circulating water cooling system to offset the thermal effect generated during the illumination process. The target pollutant was rhodamine B(RhB), and 5 mg photocatalyst was dispersed in 50 mL RhB(10 mg/L). Before the photoreaction, the suspension was stirred in a dark environment for 30 min to achieve the adsorption-degradation equilibrium, and then the photocatalytic degradation experiment was carried out under continuous stirring. During the reaction, 3–4 ml samples were taken every 15 min, and suspended particles were removed by 0.22 µm cellulose membrane filtration. The absorbance of the filtrate was determined by UV-2600 ultraviolet-visible spectrophotometer at the characteristic absorption wavelength of RhB λ max = 555 nm, and the residual concentration of RhB was calculated according to Lambert-Beer 's law. The calculation formula of the degradation rate is as follows: Degradation(%)=(1 − C t /C 0 )×100%, where C 0 is the initial concentration of RhB after adsorption equilibrium, and C t is the concentration when the illumination time is t. 3. Results and Discussion 3.1 XRD Analysis The crystal structures of NH₂-UiO-66, UT, UTPA composites, and pure PANI were comprehensively characterized via X-ray diffraction (XRD) analysis. Figure 1 (a) shows the XRD pattern of pristine UiO-66, which is consistent with previously reported UiO-66 materials [ 16 ]. Figure 1 (b) displays the XRD patterns of UT, UTPA, and pure PANI alongside the standard pattern for rutile-phase TiO₂. Pure PANI exhibits an absorption peak at 20.5°, characteristic of its amorphous structure [ 17 ]. In the UT and UTPA composites, characteristic diffraction peaks of rutile TiO₂ (JCPDS: 650190) are clearly observed, consistent with the standard pattern. These peaks correspond to 2θ = 27°, 36°, 39°, 41°, 44°, and 54° and are attributed to the (110), (011), (020), (111), (120), and (121) planes of rutile-type titanium dioxide [ 18 ]. In the XRD spectrum of the composite material, the diffraction peak of TiO 2 is dominant, while the characteristic peak of UiO-66-NH 2 is relatively weak. The possible reason for this phenomenon may be that the crystallinity of TiO 2 is higher and the diffraction intensity is larger, which leads to the scattering signal of MOF skeleton to X-ray is partially obscured. There was no new diffraction peak after compounding, which indicated that the introduction of PANI did not change its crystal structure. 3.2 FT-IR Analysis The FT-IR spectra of UiO-66, UT, UTPA, and PANI are shown in Fig. 2 . In Fig. 2 (a), the NH₂-UiO-66 and UT composites exhibit a broad absorption peak at 3332 cm⁻¹. This peak originates from the -OH groups in the solvent (DMF), whose molecules interact via hydrogen bonding within the MOF pores [ 19 – 20 ]. The bending vibration at 1400 cm⁻¹ originates from the -NH₂ group in 2-aminoterephthalic acid, confirming the presence of amino groups in the ligand. Vibrations at 1200 cm⁻¹ and 1300 cm⁻¹ stem from the -COOH group in the ligand. Vibrations at 800 cm⁻¹–950 cm⁻¹ confirm the presence of aromatic rings in the ligand, while those at 450 cm⁻¹ and 510 cm⁻¹ correspond to Ce-O and Ti-O bonds, indicating the formation of metal centers. In Fig. 2 (b), the vibrations at 1600 cm⁻¹–1500 cm⁻¹ originate from the aromatic ring in polyaniline, while the vibration at 1300 cm⁻¹ corresponds to the C–N stretching vibration in aniline [ 21 – 22 ] and the metal-oxygen bond in UT, confirming the successful complexation of UT with polyaniline. 3.3 XPS Analysis XPS analysis was performed on UTPA (20 µL, CTAB), with results shown in Fig. 3 . The full spectrum (Fig. 3 a) reveals the coexistence of Ce, Ti, C, N, and O elements within the composite material. In the C 1s spectrum (Fig. 3 b), the binding energy at 284.4 eV corresponds to C–C bonds. A satellite peak at approximately 291.5 eV, higher in binding energy, originates from π–π bonds within the benzene ring. The binding energy at 286.7 eV corresponds to the C = N bond, confirming the presence of aniline in the composite. The binding energy at 288.2 eV is attributed to the carboxyl group in the ligand, while the binding energy at 285.5 eV originates from the C-N bond in the -NH₂ group of the ligand. Figure 3 c shows the N1s spectrum. The binding energy at 399.6 eV corresponds to the -N= bond, attributed to the quinone imine. The binding energy at 401 eV corresponds to the -NH-, further confirming the presence of polyaniline. The binding energy at 398.1 eV corresponds to the -C-N- bond originating from the amino group in the ligand. In the O1s spectrum (Fig. 3 d), the binding energy at 530.3 eV corresponds to the metal-oxygen bond originating from TiO₂ and UiO-66 in the composite material. The peaks at 531.7 eV and 533.1 eV are attributed to the C = O bond and C-O bond, respectively, confirming the presence of carboxyl groups. Figure 3 e displays the Ce 3d orbital spectrum, revealing that Ce in the composite exists as a mixed valence state of Ce³⁺ and Ce⁴⁺. The peaks at 885.1 eV and 881.5 eV correspond to the Ce³⁺ 3d⁵/² orbital, while those at 901.9 eV and 904.2 eV belong to the Ce³⁺ 3d³/² orbital. while the binding energies at 898.9 eV and 887.2 eV correspond to the Ce⁴⁺ 3d₅/₂ orbital, and the peak at 907.2 eV belongs to the Ce⁴⁺ 3d₃/₂ orbital [ 23 – 24 ]. Figure 3 f shows the Ti 2p spectrum, where 458.9 eV corresponds to the Ti 2p₃/₂ binding energy and 464.5 eV to the Ti 2p₁/₂ binding energy, consistent with Ti⁴⁺ in rutile TiO₂. 3.4 TEM and SEM Analysis To investigate the morphology and microstructure of the composite materials, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations were conducted on UiO-66, UT, and UTPA materials. Figure 4 a and 4 b show SEM images of pristine UiO-66 and UT composite with TiO₂, respectively. The synthesized UiO-66 particles exhibit uniform distribution with an average size of 3–5 µm, featuring close interfacial contact between particles, indicating high structural homogeneity of the composite. Figures 4 c and 4 d present SEM images of UTPA (20 µL, CTAB). PANI is observed to uniformly coat the UT surface, a finding corroborated by TEM images (Fig. 4 e and 4 f). This PANI-coated UT forms a core-shell structure that not only provides an efficient channel for charge transport, enabling rapid interfacial electron transfer, but also exhibits structural stability. The polymer coating suppresses particle agglomeration. EDS mapping reveals uniform distribution of C, N, O, Ce, and Ti elements throughout the composite, with no discernible elemental clustering or segregation. 3.5 BET Analysis Table 1 Specific Surface Area, Pore Volume, and Pore Size Distribution of UiO-66, UT, and UTPA Sample Specific surface area(m 2 /g) Pore volume(cm 3 /g) Average crystallite (nm) UiO-66 6.275 m 2 /g 0.041 cm 2 /g 3.406 nm UT 11.480 m 2 /g 0.047 cm 2 /g 3.814 nm UTPA 20.245 m 2 /g 0.178 cm 2 /g 20.046 nm The specific surface area and pore size distribution of UiO-66, UT, and UTPA materials were analyzed using N₂ adsorption-desorption and Barrett-Joyner-Halenda (BJH) techniques. As shown in Table 1 , the composite materials with TiO₂ and PANI exhibited significantly enhanced specific surface areas, reaching 20.245 m²/g. This represents increases of 68.9% and 43.2% compared to pure UiO-66 (6.275 m²/g) and binary UT materials (11.480 m²/g), respectively. Figure 5 displays the N₂ adsorption-desorption isotherms for the three materials. Within the relative pressure range (P/P₀) of 0–1.0, all three materials exhibit Type IV isotherms with distinct H₃ hysteresis loops, confirming their mesoporous structures [ 25 – 26 ]. The combination of high specific surface area and mesoporous structure enhances dye adsorption on the composite materials. This increases the number of active sites on the surface while shortening the distance for photo-generated electrons and holes to transfer to the sample. It also partially suppresses the recombination of photo-generated carriers, thereby enhancing the redox reaction efficiency and improving photocatalytic activity. 3.6 UV-vis DRS Analysis In order to explore the light absorption properties of the composites, UV-vis DRS test was carried out. In Fig. 6 (a), TiO 2 only has a strong absorption in the ultraviolet region. Compared with TiO 2 , the light absorption of UT composites is extended from the ultraviolet region to the visible region, but there is no significant change in the light absorption range compared with UiO-66. In Fig. 6 (b), the light absorption of the binary material UT was significantly enhanced in the visible region after compounding with PANI, indicating that PANI effectively enhanced the light absorption performance of the composite. The band gap Eg of the semiconductor can be estimated according to the Tauc equation: (αhν) n =B(hν-Eg), where α is the absorption coefficient, h is the Planck constant, n is 2 or 1/2 depending on the type of semiconductor and the electronic transition properties, ν is the optical frequency, B is the proportional constant, Eg is the band gap energy, if the material is a direct semiconductor: n = 1/2, indirect semiconductor: n = 2. The tangent line is drawn by the relationship change diagram and intersects with the x-axis, and the intersection point is the band gap Eg of the material. It can be seen from Fig. 7 that the band gap of single UiO-66 is 1.81 eV, the band gap of TiO 2 is 3.00 eV, and the band gap of UT, PANI and UTPA is 1.75 eV, 2.06 eV and 1.24 eV, respectively. Compared with UiO-66, the band gap of UT composite does not change much, which may be attributed to the poor matching of the band structure between the two materials. The band gap of UTPA is significantly reduced compared with the single UiO-66 and UT materials. The reduction of the band gap enhances the response of the material to visible light, which makes the photocatalytic performance of the composite material significantly improved. 3.7 Electrochemical Performance Analysis Electrochemical impedance spectroscopy was employed to investigate the charge transfer kinetics of a series of composite materials. As shown in Fig. 8 (a), compared to pure UiO-66, UT, and PANI, the UTPA composite exhibited the smallest impedance arc radius, indicating the lowest resistance during charge transfer and the best electron transfer capability and charge transfer rate. This is attributed to the increased specific surface area of the composite material through the incorporation of PANI, which generates additional electron transfer pathways, thereby enhancing the heterogeneous electron transfer process [ 27 ]. To further validate charge separation efficiency, transient photocurrent responses were recorded under intermittent UV illumination (Fig. 8 b). The UTPA composite exhibited the highest photocurrent density. The rapid photocurrent generation and stability during multiple switching cycles confirm the composite's ability to sustain highly efficient charge separation. 3.8 Photocatalytic Properties During the preparation of composite materials, various types of surfactants were incorporated to investigate their effects on photocatalytic performance (Fig. 9 a). Cationic surfactant (CTAB), anionic surfactant (SDS), nonionic surfactant (PVP), and a control without surfactant were added, respectively. The UTPA composite without any surfactant showed significantly lower RhB degradation efficiency at 60 min compared to those with surfactants. Among the three surfactant-amended composites, the CTAB-amended composite exhibited the highest RhB degradation rate, reaching 99.90% at 60 min and 99.95% at 75 min. This may be attributed to surfactants enhancing dye adsorption on the material surface. As a cationic surfactant, CTAB forms micelles on the surface, promoting compact polymerization of PANI. This increases the transfer rate of photogenerated carriers during photocatalysis, thereby accelerating the photocatalytic degradation of RhB [ 28 ]. To investigate the effect of different aniline concentrations on photocatalytic performance, ternary composite materials with varying aniline concentrations were prepared for comparison (Fig. 9 b). As shown in the figure, pure PANI exhibited the lowest degradation efficiency for RhB. With increasing aniline concentration, the degradation efficiency of the composites first increased and then decreased. The composite containing 20 µL of aniline demonstrated the highest degradation efficiency, achieving a higher degradation rate than other samples under identical conditions. This indicates that the optimal aniline content effectively facilitates charge separation and increases contact area with pollutants, thereby enhancing photocatalytic activity. Conversely, excessively high aniline concentrations may cover active sites on the material surface, hindering effective contact between the dye and catalyst and consequently reducing photocatalytic efficiency [ 29 ]. The photocatalytic degradation effects of TiO 2 , UiO-66, UT, UTPA (20 µL, CTAB ) and without catalyst were compared under the same conditions (Fig. 9 c). The self-degradation of RhB under ultraviolet light without catalyst can be ignored (< 10%). The degradation efficiency of RhB by single UiO-66 is the slowest, and the degradation rate is 77.04% under ultraviolet light for 60 min. The degradation rate of single TiO 2 is 78.04% at 60 min. The degradation efficiency of RhB by binary composite UT is 95.11% at 60 min. The degradation rate of RhB by UTPA composite is the most significant, and the degradation rate is 99.90% at 60 min under the same conditions. This indicates that the UiO-66 material significantly improves its photocatalytic performance after compounding with TiO 2 and PANI. The UV-visible absorption spectrum (Fig. 10 d) showed that the characteristic peak of RhB (555nm ) gradually decreased with time, confirming the efficient mineralization of the dye and no intermediate product accumulation. Kinetics fitting of composite materials prepared under different conditions (Fig. 10 a,b) reveals that a series of materials exhibit quasi-first-order kinetics for photocatalytic degradation of RhB, described by the model ln(C 0 /C) = kt, where k is the kinetic rate constant, t is the reaction time, C 0 is the initial concentration of RhB, and C is the concentration of RhB at time t. The composite incorporating 20 µL aniline and utilizing CTAB as the surfactant exhibited the highest rate constant (k = 0.0939 min⁻¹), which is 3.51 times that of the pristine UiO-66 material (k = 0.0267 min⁻¹) and 2.18 times that of the binary UT composite (k = 0.043 min⁻¹). This indicates that compositing with TiO₂ and PANI effectively enhances the photocatalytic degradation performance of Ce-based UiO-66 materials. In order to evaluate the reusability of the composites, continuous cyclic degradation tests were performed on the UTPA material under the same experimental conditions (Fig. 11 ). After each degradation, the catalyst was recovered by centrifugation and washed with deionized water and anhydrous ethanol alternately. After drying, it was put into the next round of use. After 5 cycles, the UTPA composite still showed high photocatalytic activity, indicating that the material had good structural stability and less photocorrosion during photocatalytic degradation. The main reason for the decrease in efficiency is the inevitable physical mass loss in the centrifugal recovery process, rather than the deactivation of the material itself. To investigate the roles of various active substances in the photocatalytic degradation of RhB, different types of radical scavengers were introduced into the catalytic system. Under identical experimental conditions, L-ascorbic acid, tert-butanol, and EDTA-2Na were selected as scavengers for superoxide radicals (•O₂⁻), •OH radical, and active hole (h⁺) scavengers, respectively. The photocatalyst used was the sample UTPA (20 µL/CTAB). As shown in Fig. 12 , the addition of L-ascorbic acid exhibited the most significant inhibitory effect on RhB degradation efficiency, reducing it from 99.90% to 52.97% within 60 min. This result indicates that •O₂⁻ is the primary active species responsible for RhB oxidation. To further elucidate the mechanism of photocatalytic degradation of RhB by UTPA materials and the structure of their heterojunction, Mott-Schottky measurements were performed on UiO-66, TiO₂, and PANI. These were combined with UV-vis DRS measurements to calculate their conduction band potential and valence band potential. Mott-Schottky measurements primarily assess the flat-band potential and charge carrier density. As shown in Fig. 13 , the positive slope of the UiO-66 and TiO₂ curves indicates n-type semiconductor behavior, while the negative slope of the PANI curve signifies p-type semiconductor behavior. The flat-band potential of semiconductor materials can be roughly calculated from the x-intercept of the linear region in the Mott-Schottky curve. The flat-band potential of UiO-66 is -1.11 eV. Since the conduction band potential of an n-type semiconductor is 0.1 eV more negative than the flat-band potential, the CB potential of UiO-66 is -1.21 eV. Based on the relationship between the Normalized Hydrogen Electrode (NHE) and the Ag/AgCl electrode, E NHE = E Ag/AgCl +0.197, yielding a CB potential of -1.01 eV for UiO-66. UV-vis DRS measurements indicate a bandgap of 1.81 eV for UiO-66. Using the equation Eg = VB - CB, the VB of UiO-66 is calculated as 0.80 eV. The flat-band potential of TiO₂ is -0.50 eV. Based on the above relationship, its CB is -0.40 eV, and its bandgap is 3.0 eV, thus its VB is 2.6 eV. The flat-band potential of PANI is 0.84 eV. Since the flat-band potential of a p-type semiconductor is close to its HOMO energy level, it is approximated as equal to the HOMO energy level. Thus, the HOMO energy level of PANI is 0.84 eV. The flat-band potential of a p-type semiconductor is 0.1 eV more negative than its band edge potential. The band gap of PANI is 2.06 eV. Therefore, based on calculations, the LUMO energy level of PANI is -1.12 eV. Based on the above characterization and analysis, the possible mechanism for photocatalytic degradation of RhB by the UTPA composite material is discussed and inferred. Based on the energy level arrangement of the three components and the results of radical scavenging experiments, it is inferred that the UTPA composite forms a ternary synergistic Z-type heterojunction system [ 30 ]. In this system, PANI, as the organic conductive polymer, acts as the charge transport medium. The specific mechanism is as follows: Under UV irradiation, UiO-66 and TiO₂ are simultaneously excited, generating electron-hole pairs. Electrons on the TiO₂ CB transfer through PANI to the UiO-66 VB, where they recombine with holes. This spatially separates charge carriers, with PANI serving as the electron transfer pathway. Its conjugated structure and matched LUMO/HOMO levels enable directed carrier recombination, broadening the light absorption range and accelerating charge transfer. Electrons accumulate on the CB of UiO-66, whose CB potential of -1.01 eV is more negative than the standard reduction potential of O₂/•O₂⁻ (-0.33 eV vs NHE). Consequently, electrons enriched on the UiO-66 CB react with adsorbed oxygen (O₂) to generate superoxide radicals (•O₂⁻) with strong oxidizing capabilities [ 31 ], cleaving the RhB dye molecules to yield CO₂ and H₂O ultimately. Figure 14 illustrates this process. 4. Conclusions Ce-UiO-66-NH 2 was successfully synthesized by oil bath method. TiO 2 was successfully introduced on the basis of Ce-UiO-66-NH 2 , and binary UiO-66-NH 2 /TiO 2 (UT)composites were constructed. On the basis of binary UT materials, polyaniline (PANI) was introduced by in-situ oxidation polymerization, and UiO-66-NH 2 /TiO 2 /PANI (UTPA) ternary composites were successfully prepared. The characterization results show that PANI is uniformly coated on the surface of UT, and a good interfacial interaction is formed between the three. The introduction of appropriate amount of PANI increases the specific surface area of the composite material, enhances the visible light absorption capacity, and significantly promotes the separation and transmission of photogenerated carriers. Photocatalytic degradation experiments showed that the degradation rate of RhB by UTPA was more than 99.9% in 60 min, which was significantly better than that of single component and UT binary material. Free radical capture experiments showed that superoxide radicals (·O 2 − ) were the main active species in the reaction system. Combined with the analysis of energy band structure, the photocatalytic enhancement mechanism of UTPA ternary heterojunction was proposed.The cyclic stability test confirmed that the composite material had good reusability. Declarations • Funding • Competing interests The authors declare no competing financial interests or personal relationships that could influence this work. • Ethics approval and consent to participate Not applicable. • Consent for publication All authors have read and approved the final manuscript for publication. • Availability of data and materials The datasets generated and analyzed during this study are available from the corresponding author upon reasonable request. • Data Availability Statement The authors declare that the data supporting the findings of this study are available within the paper. Should any raw data files be needed in another format, they are available from the corresponding author upon reasonable request. Source data are provided with this paper. Author Contribution Lili Li wrote the main manuscript.Jiaxin Li prepared figures 1-4.Yuyu Ma prepared figures 6-10Jing Shu reviewed the manuscript. References Zhang, X., Wang, J., Dong, X.X., et al.: Functionalized metal-organic framewo-rks for photocatalytic degradation of organic pollutants in the environment. Chemosphere(2020). https://doi.org/10.1016/j.chemosphere.2019.125144 Munien, C., Rathilal, S., Tetteh, E.K.: Challenges and Prospects of TiO 2 -Based Photocatalysis for Wastewater Treatment: Keyword Analysis. Catalysts (2025). https://doi.org/10.3390/catal15090801 Sabzehmeidani, M.M., Karimi, H., Ghaedi, M.: CeO 2 nanofibers-CdS nanostruc-tures n–n junction with enhanced visible-light photocatalytic activity. Arab. J. Chem. 13 , 7583–7597 (2020) Banyal, R., Sonu, S., Soni, V., et al.: Synergetic photocatalytic degradation of the tetracycline antibiotic over S-scheme-based BiOBr/CuInS 2 /WO 3 ternary heterojunction photocatalyst. Solid State Sci. (2024). https://doi.org/10.1016/j.solidstatesciences.2024.107700 Rana, A., Sonu, S., Soni, V., et al.: Novel S-scheme derived Mo–Bi 2 WO 6 /WO 3 /Biochar composite for photocatalytic removal of Methylene Blue dye. J. Phys. Chem. Solids. (2025). https://doi.org/10.1016/j.jpcs.2024.112385 Cheng, L., Xiang, Q.J., Liao, Y.L., et al.: CdS-based photocatalysts. Energy Environ. Sci. 11 , 1362–1391 (2018) Ma, R., Zhang, S., Wen, T., et al.: A critical review on visible-light-response CeO 2 -based photocatalysts with enhanced photooxidation of organic pollutants. Catal. Today. (2019). https://doi.org/10.1016/j.cattod.2018.11.016 Ong, C.B., Ng, L.Y., Mohammad, A.W.: A review of ZnO nanoparticles as so-lar photocatalysts: synthesis, mechanisms and applications. Renewable and S-ustainable Energy Reviews (2018). https://doi.org/10.1016/j.rser.2017.08.020 Li, Y.F., Xia, Z.L., Yang, Q., et al.: Review on g-C 3 N 4 -based S-scheme hetero-junction photocatalysts. J. Mater. Sci. Technol. 125 , 128–144 (2022) Zhou, H.C., Long, J.R., Yaghi, O.M.: Introduction to metal–organic frameworks. Chem. Rev. 112 (2), 673–674 (2012) Parnicka, P., Lisowski, W., Klimczuk, T., et al.: A novel (Ti/Ce)UiO-X MOFs@TiO 2 heterojunction for enhanced photocatalytic performance: Boosting via Ce 4+ /Ce 3+ and Ti 4+ /Ti 3+ redox mediators. Appl. Catal. B. (2022). https://doi.org/10.1016/j.apcatb.2022.121349 Liang, R., Jing, F., Shen, L., et al.: M@ MIL-100 (Fe)(M = Au, Pd, Pt) nanocomposites fabricated by a facile photodeposition process: Efficient visible-lig-ht photocatalysts for redox reactions in water. Nano Res. 8 , 3237–3249 (2015) Liu, X., Dang, R., Dong, X.J., et al.: A sandwich-like heterostructure of TiO 2 nanosheets with MIL-100 (Fe): a platform for efficient visible-light-driven photocatalysis. Appl. Catal. B. 209 , 506–513 (2017) Lai, Y.X., Wang, F., Zhang, Y.M., et al.: UiO-66 derived N-doped carbon na-noparticles coated by PANI for simultaneous adsorption and reduction of hexavalent chromium from waste water. Chem. Eng. J. (2019). https://doi.org/10.1016/j.cej.2019.122069 Xue, Y.M., Lin, J., Fan, Y., et al.: Controllable synthesis of uniformly distri-buted hollow rutile TiO 2 hierarchical microspheres and their improved photoc-atalysis. Mater. Chem. Phys. (2013). https://doi.org/10.1016/j.matchemphys.2013.09.026 Ghamim, E.E., Walker, M., Walton., R.I.: Rapid synthesis of cerium-UiO-66 MOF nanoparticles for photocatalytic dye degradation. Dalton Trans. https://doi.org/10.1039/d3dt00890h Nosrati, R., Olad, A., Najjari, H.: Study of the effect of TiO 2 /polyaniline nan-ocomposite on the self-cleaning property of polyacrylic latex coating.Surface and Coatings Technology. 316 : 199–209 (2017) Wu, J.F., Fang, X.X., Zhu, Y.Z., et al.: Well-Designed TiO 2 @UiO-66-NH 2 Na-nocomposite with Superior Photocatalytic Activity for Tetracycline under Restricted Space. Energy Fuels. 34 , 12911–12917 (2020) Airi, A., Atzori, C., Bonino, F., et al.: A spectroscopic and computational stu-dy of a tough MOF with a fragile linker: Ce-UiO-66-ADC. Dalton Transactions (2020). https://doi.org/10.1039/c9dt04112e Hadjiivanov, K.I., Panayotov, D.A., Mihaylov, M.Y., et al.: Power of infrared and Raman spectroscopies to characterize metal-organic frameworks and inv-estigate their interaction with guest molecules.Chemical Reviews (2020). https://doi.org/10.1021/acs.chemrev.0c00487 Gao, J.T., Wang, Y., Zhou, S.J., et al.: A Facile One-Step Synthesis of Fe‐D-oped g‐C 3 N 4 Nanosheets and Their Improved Visible‐Light Photocatalytic Pe-rformance. ChemCatChem. 9 (9), 1708–1715 (2017) Xu, Y.G., Ge, F.Y., Chen, Z.G., et al.: One-step synthesis of Fe-doped surface-alkalinized g-C 3 N 4 and their improved visible-light photocatalytic performance. Appl. Surf. Sci. 469 , 739–746 (2019) Paparazzo, E.: Use and misuse of X-ray photoemission spectroscopy: Ce3d s-pectra of Ce 2 O 3 and CeO 2 . J. Phys.: Condens. Matter. (2019). https://doi.org/10.1088/1361-648X/aad248 Pfau, A., Schierbaum, K.D.: The electronic structure of stoichiometric and reduced CeO 2 surfaces: an XPS, UPS and HREELS study. Surf. Sci. 321 , 71–80 (1994) Mitra, M., Ahamed, S.T., Ghost, A., et al.: Polyaniline/reduced graphene oxide composite-enhanced visible-light-driven photocatalytic activity for the degradation of organic dyes. ACS Omega. (2019). https://pubs.acs.org/doi/ 10.1021/acsomega.8b02941 Gilja, V., Vrban, I., Mandić, V., et al.: Preparation of a PANI/ZnO composit-e for efficient photocatalytic degradation of acid blue. Polymers. (2018). https://doi.org/10.3390/polym10090940 Yang, Z.L., Peng, D.Y., Zeng, H.Y., et al.: Enhanced photocatalytic performance of heterostructure BiOBr/PPy for Cr(VI) reduction and dye degradation. Colloids Surf. A: Physicochem Eng. Aspects. (2024). https://doi.org/10.1016/j.colsurfa.2023.132647 Wu, W.Z., Zhang, L.J., Zhai, X.J., et al.: Preparation and photocatalytic acti-vity analysis of nanometer TiO 2 modified by surfactant. Nanomaterials Nanatechnol. 8 , 1–8 (2018) Liu, L., Ding, L., Liu, Y.G., et al.: A stable Ag 3 PO 4 @PANI core@shell hybr-id: Enrichment photocatalytic degradation with π-π conjugation. Appl. Catal. B. 201 , 92–104 (2016) Sin, J.C., Lam, S.M., Zeng, H.H., et al.: Design and synthesis of Fe 2 WO 6 / Eu-doped BiOBr nanocomposite: A novel 0D/2D Z-scheme heterojunction sy-stem for simultaneous boosted visible-light driven photocatalytic bisphenol A degradation and Cr(VI) reduction. Ceram. Int. 50 , 5372–5383 (2024) Xu, H., Dai, J.C., Fang, K.J., et al.: BiOI/PPy/cotton photocatalytic fabric for efficient organic dye contaminant degradation and self-cleaning application. Colloids Surf., A. (2023). https://doi.org/10.1016/j.colsurfa.2023.131862 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-9454538\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":626001797,\"identity\":\"f50e6ce7-2dee-494a-81f1-36be29429caf\",\"order_by\":0,\"name\":\"Lili Li\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Northeast Petroleum University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Lili\",\"middleName\":\"\",\"lastName\":\"Li\",\"suffix\":\"\"},{\"id\":626001798,\"identity\":\"adbbab82-d436-4cad-93d3-e46137cec51b\",\"order_by\":1,\"name\":\"Jiaxing Li\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Northeast Petroleum University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Jiaxing\",\"middleName\":\"\",\"lastName\":\"Li\",\"suffix\":\"\"},{\"id\":626001799,\"identity\":\"709a72bc-75ee-4749-9df9-c6484e80476c\",\"order_by\":2,\"name\":\"Yuyu Ma\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Northeast Petroleum University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Yuyu\",\"middleName\":\"\",\"lastName\":\"Ma\",\"suffix\":\"\"},{\"id\":626001800,\"identity\":\"e7c25a1a-d47a-44ed-adb9-a598d01cdf1d\",\"order_by\":3,\"name\":\"Jing Shu\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYBAC+RkMDMZ/ftjw8PM3EKnF4AYQ8/akyUjOOECsFgkgwcN22MagIYFYLdI9BgUSPOd5DBgOMH74mEOEFvk5ZwwMDCxu85gzNzBLztxGjDU3cgwMEnhu81g2HGBj5iVaywG2czwGBxJI0GLYwHaABC0GN9IKjBl7knkkZxxsJs4v8jOStxkz/LCz5+dvPvjhI1EOY2BgM4DQjA3EqQcC5gdEKx0Fo2AUjIKRCQB1xTQlXjQfXQAAAABJRU5ErkJggg==\",\"orcid\":\"\",\"institution\":\"Northeast Petroleum University\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Jing\",\"middleName\":\"\",\"lastName\":\"Shu\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-04-18 06:08:07\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-9454538/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-9454538/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":108962428,\"identity\":\"37aea80f-6552-4e32-a679-94fd9d1be49a\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:03\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":82234,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003e(a) XRD pattern of NH\\u003c/strong\\u003e\\u003csub\\u003e\\u003cstrong\\u003e2\\u003c/strong\\u003e\\u003c/sub\\u003e\\u003cstrong\\u003e-UiO-66, (b) XRD patterns of UT, UTPA, PANI, and standard TiO\\u003c/strong\\u003e\\u003csub\\u003e\\u003cstrong\\u003e2\\u003c/strong\\u003e\\u003c/sub\\u003e\\u003cstrong\\u003e reference plate\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/18a4847754b760e8787571ef.png\"},{\"id\":108962431,\"identity\":\"fd2a7010-425d-4326-b0a7-af712e383aeb\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:03\",\"extension\":\"png\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":110776,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003e(a) FT-IR spectra of NH\\u003c/strong\\u003e\\u003csub\\u003e\\u003cstrong\\u003e2\\u003c/strong\\u003e\\u003c/sub\\u003e\\u003cstrong\\u003e–UiO-66 and UT composites, (b) FT-IR spectra of UTPA and pure PANI\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"2.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/0c5182cd0f76cff149d67600.png\"},{\"id\":108977953,\"identity\":\"c8e973a2-45d3-4614-a356-26898184c488\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 11:33:30\",\"extension\":\"png\",\"order_by\":3,\"title\":\"Figure 3\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":458735,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003e(a) Full XPS spectrum of the UTPA composite material; 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(b) Transient photocurrent response curves of UiO-66, UT, and UTPA\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"8.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/c81b1d98640037f644359611.png\"},{\"id\":108977847,\"identity\":\"ef677537-147a-4872-98a6-764794cf9df8\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 11:33:12\",\"extension\":\"png\",\"order_by\":9,\"title\":\"Figure 9\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":238494,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003e(a) Comparison of photocatalytic properties of UTPA (CTAB ) with different concentrations of aniline and pure PANI, (b) Comparison of photocatalytic properties of UTPA (20 μL) with different surface activities, (c) Comparison of photocatalytic properties of UiO-66, UT, TiO\\u003c/strong\\u003e\\u003csub\\u003e\\u003cstrong\\u003e2\\u003c/strong\\u003e\\u003c/sub\\u003e\\u003cstrong\\u003e, UTPA and blank group, (d) Ultraviolet-visible absorption spectrum of UTPA (20 μL, CTAB) degrading RhB under ultraviolet light irradiation\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"9.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/6b5ee706d75000460281f5eb.png\"},{\"id\":108962439,\"identity\":\"a70b45a3-cf30-4623-b47a-64f8570b7f75\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:04\",\"extension\":\"png\",\"order_by\":10,\"title\":\"Figure 10\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":124258,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003e(a) First-order kinetic fitting curves of UiO-66 and its composites, TiO₂, and pure PANI prepared under different conditions; (b) Degradation rate constants of UiO-66 and its composites, TiO₂, and pure PANI prepared under different conditions\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"10.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/d49aff941824cbbca3ef5d83.png\"},{\"id\":108962440,\"identity\":\"3e335308-40a4-479f-88e6-dd25b50daba1\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:04\",\"extension\":\"png\",\"order_by\":11,\"title\":\"Figure 11\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":36840,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003ePhotocatalytic stability test of UTPA composite\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"11.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/d023d15c6b39e467a0527f04.png\"},{\"id\":108962437,\"identity\":\"ea343b46-8964-48e6-bc58-c3b710f3a7fb\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:04\",\"extension\":\"png\",\"order_by\":12,\"title\":\"Figure 12\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":69212,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003eInvestigation of the Mechanism of RhB Photocatalytic Degradation by UTPA Using Different Types of Sacrificial Agents\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"12.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/9b798ad731136445c10ed7d7.png\"},{\"id\":108962435,\"identity\":\"b177a661-8015-4fee-8a0e-32c4608673ea\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:04\",\"extension\":\"png\",\"order_by\":13,\"title\":\"Figure 13\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":75161,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003eMott-Schottky curves of UiO-66, TiO₂, and PANI\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"13.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/377e4083563c3b3627b70933.png\"},{\"id\":108962438,\"identity\":\"4370a4a2-e293-4e73-a888-13bb5f02c989\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 09:03:04\",\"extension\":\"png\",\"order_by\":14,\"title\":\"Figure 14\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":89192,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003e\\u003cstrong\\u003eSchematic diagram of the photocatalytic degradation mechanism of RhB by UTPA composite material\\u003c/strong\\u003e\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"14.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/9bea9477fb9ee36837fd5356.png\"},{\"id\":108979984,\"identity\":\"f8668ec9-db1b-43a6-8449-2194f2a99ab3\",\"added_by\":\"auto\",\"created_at\":\"2026-05-11 12:02:55\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":2384820,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9454538/v1/f9eb9ee0-a4fd-4e0d-9d74-eea7a245523f.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Preparation of Ce-UiO-66-NH₂/TiO₂/PANI Composite and Photocatalytic Degradation of RhB\",\"fulltext\":[{\"header\":\"1. Introduction\",\"content\":\"\\u003cp\\u003eWith the acceleration of the industrialization process, its negative impact on human society is also further revealed, and energy shortages and environmental problems are becoming more and more serious. Among them, water pollution is one of the most serious problems. Some wastewater produced in industrial production contains a large number of organic pollutants and heavy metal ions, including but not limited to organic dyes, phenols, chemical fertilizers, hexavalent chromium, etc., which have great harm to the environment and human beings. Taking organic dyes as an example, more than 7\\u0026times;10\\u003csup\\u003e5\\u003c/sup\\u003e tons of commercial dyes are produced every year. These dyes have stable chemical properties and are not biodegradable in water, posing a serious threat to the environment [\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]. RhB is one of the most common organic dyes in the textile industry and industrial wastewater. Therefore, exploring new materials and technologies to degrade pollutants in sewage is of great significance for maintaining the ecological environment and human health, as well as further promoting the development of industry. As a special treatment process, advanced oxidation processes (AOPs) have attracted much attention since the 20 th century. Advanced oxidation processes include ozone oxidation, Fenton oxidation, photocatalysis and so on. Among them, photocatalytic degradation technology is widely used in the field of sewage treatment because of its advantages of simplicity, high efficiency, no pollution and low cost. Photocatalytic technology is based on a series of redox reactions between photocatalyst and pollutants in sewage under light conditions, and finally achieve the purpose of degrading pollutants [\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003ePhotocatalytic degradation technology offers advantages such as low cost, simple operation, and ecological harmlessness, making it a highly promising environmental remediation technique. Its fundamental principle involves three basic steps: (1) Generation of electron-hole pairs under ultraviolet or visible light irradiation, (2) Separation and migration of photo-generated electrons and holes, (3) Oxidation-reduction reactions. When the energy absorbed by the photocatalyst equals or exceeds its bandgap, electrons in the valence band (VB) are excited to the conduction band (CB), leaving behind positively charged active holes (h\\u003csup\\u003e+\\u003c/sup\\u003e) in the VB. Electrons in the CB react with dissolved O₂ in water to form superoxide radicals (\\u0026bull;O₂⁻), while h⁺ in the VB reacts with water molecules to generate hydroxyl radicals (\\u0026bull;OH). These reactive species possess strong oxidizing capabilities, degrading organic pollutants into H₂O and CO₂ [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e]. However, in single photocatalytic materials, photogenerated electron-hole pairs rapidly recombine after separation, significantly impairing photocatalytic degradation efficiency.\\u003c/p\\u003e \\u003cp\\u003eConventional photocatalysts typically comprise semiconductor materials such as metal oxides and sulfides, carbon-based composites, and nitrides [\\u003cspan additionalcitationids=\\\"CR7 CR8\\\" citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e]. Metal-organic frameworks (MOFs) represent a class of inorganic-organic multifunctional metal hybrid materials. They are crystalline porous coordination polymers formed by metal ions connected through coordination bonds with organic ligand frameworks. MOFs exhibit large specific surface areas, well-defined pore structures, and structural design flexibility. Consequently, they hold broad application prospects in separation, gas storage, catalysis, photocatalysis, CO₂ capture, and other fields [\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e]. However, many pristine MOFs suffer from poor light absorption, rapid electron-hole recombination, low charge transfer efficiency, and poor long-term cycling stability. To address these issues, common strategies include doping metal ions to alter their band structure or compositing them with semiconductor materials to form heterojunctions, thereby promoting photogenerated charge transfer and creating additional active sites [\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e]. Liang et al photodeposited Au, Pd and Pt noble metals on MIL-100(Fe) to decompose MO, respectively.Studies have shown that the deposited noble metal nanoparticles are beneficial to the transfer of excited photoelectrons triggered by visible light. And prolong the life of the carrier, effectively promote the photodegradation of MO [\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]. Combining MOF materials with semiconductor photocatalysts can also greatly improve the photocatalytic efficiency. Semiconductor materials have excellent light capture ability and rich surface active sites. Adding semiconductors to MOFs composites can form heterojunctions. The formation of heterojunctions will adjust the band gap of the material and promote the separation and migration of photogenerated carriers, thereby improving the photocatalytic performance of the material. Liu et al.synthesized TiO\\u003csub\\u003e2\\u003c/sub\\u003e@MIL-100-Fe nanosheets with a sandwich structure by self-assembly method. MIL-100-Fe has a high specific surface area, which can effectively expose more active sites, effectively prevent the aggregation of TiO\\u003csub\\u003e2\\u003c/sub\\u003e, and improve the efficiency of photogenerated electron generation, separation and transfer. The material has excellent photocatalytic activity for methylene blue (MB), which is 45 times and 2 times that of single TiO\\u003csub\\u003e2\\u003c/sub\\u003e nanosheets and MIL-100-Fe, respectively [\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]. Conductive polymers with π-conjugated systems such as polyaniline (PANI) have the advantages of high electron-hole pair mobility, high absorption coefficient and environmental stability. The combination with MOF materials can effectively improve the photocatalytic efficiency and make up for the lack of stability of MOF materials [\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eIn order to effectively improve the photocatalytic performance of MOF materials, Ce-based NH\\u003csub\\u003e2\\u003c/sub\\u003e-UiO-66 materials were prepared by oil bath heating method in this experiment. The Ce-UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e/TiO\\u003csub\\u003e2\\u003c/sub\\u003e binary material ( UT ) was constructed by adding pre-synthesized TiO\\u003csub\\u003e2\\u003c/sub\\u003e powder with different mass during the synthesis process. The binary UT material was prepared by in-situ oxidation polymerization. UTPA ternary composite material was prepared by in-situ oxidation polymerization. Rhodamine B (RhB) was used as the target pollutant, and the photocatalytic degradation performance of the composite material on RhB under ultraviolet light was investigated. The effects of different surfactants and different aniline concentrations on the photocatalytic performance were studied. The mechanism of the heterojunction of the composite material was clarified by free radical trapping experiments and band alignment, and the charge transfer process in the system was clarified. The results show that the photocatalytic degradation performance of UTPA composite material is significantly improved compared with that of single material and binary UT material.\\u003c/p\\u003e\"},{\"header\":\"2. Experimental\",\"content\":\"\\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.1 Materials\\u003c/h2\\u003e \\u003cp\\u003eN, N-Dimethylformamide (DMF) was purchased from Guangdong Wenglong Chemical Reagent Co., Ltd. 2-Aminoterephthalic acid was purchased from Shandong Keyuan Biochemical Co., Ltd. Ammonium cerium nitrate, tert-butanol, and sodium dodecyl sulfate (SDS) were purchased from Shanghai McLean Biochemical Co., Ltd. Tetrabutyl titanate (TBT) and Rhodamine B (RhB) were obtained from Beijing Chemical Co., Ltd. Ammonium persulfate (APS) and disodium ethylenediaminetetraacetate (EDTA-2Na) were sourced from Tianjin Damiao Chemical Reagent Factory. L-ascorbic acid was purchased from Tianjin Kemiou Chemical Reagent Co., Ltd. Polyvinylpyrrolidone (PVP) was purchased from Shanghai Boao Biotechnology Co., Ltd. Cetyltrimethylammonium bromide (CTAB) was purchased from Tianjin Dagang Yizhong Chemical Factory. Anhydrous ethanol was purchased from Shenyang Huadong Reagent Factory. Hydrochloric acid was purchased from Shanghai Chemical Reagent Factory, and aniline was purchased from Aladdin Biotechnology Co., Ltd. The deionized water and all chemical reagents used in this experiment were used directly without further purification.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec4\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.2 Synthesis of TiO₂\\u003c/h2\\u003e \\u003cp\\u003eTiO₂ was synthesized via the hydrothermal method according to a previously reported procedure [\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e]. A mixture of 0.1 mol TBT and 34 g hydrochloric acid (38%) was prepared in a beaker, transferred to a Teflon-lined autoclave, heated at 150\\u0026deg;C for 24 hours, and then cooled to room temperature. After the reactor cooled to room temperature, the precipitate was separated from the suspension by centrifugation. It was washed three times with alternating portions of anhydrous ethanol and water, then dried in an air oven at 60\\u0026deg;C for 12 hours.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec5\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.3 Synthesis of UT\\u003c/h2\\u003e \\u003cp\\u003eDissolve 1.2 mmol of 2-aminoterephthalic acid in 8 mL of DMF, add 0.005 g of TiO₂, dissolve 1.4 mmol of ammonium cerium nitrate in 2.7 mL of deionized water, combine both solutions in a flask, seal the flask, and heat with stirring at 100\\u0026deg;C in an oil bath for 30 min. After cooling, centrifuge the mixture. Wash the residue three times with DMF and anhydrous ethanol, respectively. Dry at 60\\u0026deg;C for 12 h. A single NH₂-UiO-66 material was prepared without adding TiO₂.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.4 Synthesis of UTPA\\u003c/h2\\u003e \\u003cp\\u003eDissolve 20 \\u0026micro;L (10 \\u0026micro;L, 20 \\u0026micro;L, 40 \\u0026micro;L) of aniline in 15 mL of 1 M hydrochloric acid. Add 20 mg of surfactant (CTAB, SDS, PVP, Blank) and 0.1 g of composite material, then mix thoroughly. Dissolve 1.5 mmol APS in 15 mL 1 M hydrochloric acid. Add this solution to the aniline mixture under an ice-water bath, stirring until the mixture turns dark green. Centrifuge the dark green mixture, wash three times with alternating deionized water and anhydrous ethanol, then dry at 60\\u0026deg;C for 12 hours to obtain the composite material.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec7\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.5 Characterization Methods\\u003c/h2\\u003e \\u003cp\\u003eThe crystalline phases of the catalyst were characterized using X-ray diffraction (XRD, D/max-2200pc X-ray diffractometer with CuKα radiation) (CuKα radiation, tube voltage 40 kV, tube current 40 mA min⁻\\u0026sup1;, scanning speed 5\\u0026deg;min⁻\\u0026sup1;). Infrared spectroscopy of molecular vibrations was performed using a Fourier Transform Infrared Spectrometer (FTIR, Tensor27, Fairburn Precision Instruments (Shanghai) Co., Ltd.); Surface area analysis was conducted using an N₂ adsorption-desorption instrument (BET, NOVA2000e, Shanghai Chuangsen Instruments Co., Ltd.); (TEM, FEI Talos f200x, FEI) to examine material morphology; XPS analysis employed a Semefi250x X-ray photoelectron spectrometer; UV-1600PC UV-visible spectrophotometer measured diffuse reflectance UV-visible spectra over 200\\u0026ndash;800 nm; An electrochemical workstation equipped with a standard three-electrode system (Shanghai Chenhua Instruments Co., Ltd.) was employed to obtain transient photocurrent response spectra, electrochemical impedance spectra, and Mott-Schottky spectra.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec8\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e2.6 Photocatalytic Study\\u003c/h2\\u003e \\u003cp\\u003eThe light source of the photocatalytic degradation reaction uses a 250 W mercury lamp, and the light source is equipped with a circulating water cooling system to offset the thermal effect generated during the illumination process. The target pollutant was rhodamine B(RhB), and 5 mg photocatalyst was dispersed in 50 mL RhB(10 mg/L). Before the photoreaction, the suspension was stirred in a dark environment for 30 min to achieve the adsorption-degradation equilibrium, and then the photocatalytic degradation experiment was carried out under continuous stirring. During the reaction, 3\\u0026ndash;4 ml samples were taken every 15 min, and suspended particles were removed by 0.22 \\u0026micro;m cellulose membrane filtration. The absorbance of the filtrate was determined by UV-2600 ultraviolet-visible spectrophotometer at the characteristic absorption wavelength of RhB λ\\u003csub\\u003emax\\u003c/sub\\u003e\\u0026thinsp;=\\u0026thinsp;555 nm, and the residual concentration of RhB was calculated according to Lambert-Beer 's law. The calculation formula of the degradation rate is as follows: Degradation(%)=(1\\u0026thinsp;\\u0026minus;\\u0026thinsp;C\\u003csub\\u003et\\u003c/sub\\u003e/C\\u003csub\\u003e0\\u003c/sub\\u003e)\\u0026times;100%, where C\\u003csub\\u003e0\\u003c/sub\\u003e is the initial concentration of RhB after adsorption equilibrium, and C\\u003csub\\u003et\\u003c/sub\\u003e is the concentration when the illumination time is t.\\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"3. Results and Discussion\",\"content\":\"\\u003cdiv id=\\\"Sec10\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.1 XRD Analysis\\u003c/h2\\u003e \\u003cp\\u003eThe crystal structures of NH₂-UiO-66, UT, UTPA composites, and pure PANI were comprehensively characterized via X-ray diffraction (XRD) analysis. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e(a) shows the XRD pattern of pristine UiO-66, which is consistent with previously reported UiO-66 materials [\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e]. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e(b) displays the XRD patterns of UT, UTPA, and pure PANI alongside the standard pattern for rutile-phase TiO₂. Pure PANI exhibits an absorption peak at 20.5\\u0026deg;, characteristic of its amorphous structure [\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e]. In the UT and UTPA composites, characteristic diffraction peaks of rutile TiO₂ (JCPDS: 650190) are clearly observed, consistent with the standard pattern. These peaks correspond to 2θ\\u0026thinsp;=\\u0026thinsp;27\\u0026deg;, 36\\u0026deg;, 39\\u0026deg;, 41\\u0026deg;, 44\\u0026deg;, and 54\\u0026deg; and are attributed to the (110), (011), (020), (111), (120), and (121) planes of rutile-type titanium dioxide [\\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e]. In the XRD spectrum of the composite material, the diffraction peak of TiO\\u003csub\\u003e2\\u003c/sub\\u003e is dominant, while the characteristic peak of UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e is relatively weak. The possible reason for this phenomenon may be that the crystallinity of TiO\\u003csub\\u003e2\\u003c/sub\\u003e is higher and the diffraction intensity is larger, which leads to the scattering signal of MOF skeleton to X-ray is partially obscured. There was no new diffraction peak after compounding, which indicated that the introduction of PANI did not change its crystal structure.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec11\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.2 FT-IR Analysis\\u003c/h2\\u003e \\u003cp\\u003eThe FT-IR spectra of UiO-66, UT, UTPA, and PANI are shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e. In Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e(a), the NH₂-UiO-66 and UT composites exhibit a broad absorption peak at 3332 cm⁻\\u0026sup1;. This peak originates from the -OH groups in the solvent (DMF), whose molecules interact via hydrogen bonding within the MOF pores [\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e]. The bending vibration at 1400 cm⁻\\u0026sup1; originates from the -NH₂ group in 2-aminoterephthalic acid, confirming the presence of amino groups in the ligand. Vibrations at 1200 cm⁻\\u0026sup1; and 1300 cm⁻\\u0026sup1; stem from the -COOH group in the ligand. Vibrations at 800 cm⁻\\u0026sup1;\\u0026ndash;950 cm⁻\\u0026sup1; confirm the presence of aromatic rings in the ligand, while those at 450 cm⁻\\u0026sup1; and 510 cm⁻\\u0026sup1; correspond to Ce-O and Ti-O bonds, indicating the formation of metal centers. In Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e(b), the vibrations at 1600 cm⁻\\u0026sup1;\\u0026ndash;1500 cm⁻\\u0026sup1; originate from the aromatic ring in polyaniline, while the vibration at 1300 cm⁻\\u0026sup1; corresponds to the C\\u0026ndash;N stretching vibration in aniline [\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e] and the metal-oxygen bond in UT, confirming the successful complexation of UT with polyaniline.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec12\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.3 XPS Analysis\\u003c/h2\\u003e \\u003cp\\u003eXPS analysis was performed on UTPA (20 \\u0026micro;L, CTAB), with results shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e. The full spectrum (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ea) reveals the coexistence of Ce, Ti, C, N, and O elements within the composite material. In the C 1s spectrum (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003eb), the binding energy at 284.4 eV corresponds to C\\u0026ndash;C bonds. A satellite peak at approximately 291.5 eV, higher in binding energy, originates from π\\u0026ndash;π bonds within the benzene ring. The binding energy at 286.7 eV corresponds to the C\\u0026thinsp;=\\u0026thinsp;N bond, confirming the presence of aniline in the composite. The binding energy at 288.2 eV is attributed to the carboxyl group in the ligand, while the binding energy at 285.5 eV originates from the C-N bond in the -NH₂ group of the ligand. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ec shows the N1s spectrum. The binding energy at 399.6 eV corresponds to the -N= bond, attributed to the quinone imine. The binding energy at 401 eV corresponds to the -NH-, further confirming the presence of polyaniline. The binding energy at 398.1 eV corresponds to the -C-N- bond originating from the amino group in the ligand. In the O1s spectrum (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ed), the binding energy at 530.3 eV corresponds to the metal-oxygen bond originating from TiO₂ and UiO-66 in the composite material. The peaks at 531.7 eV and 533.1 eV are attributed to the C\\u0026thinsp;=\\u0026thinsp;O bond and C-O bond, respectively, confirming the presence of carboxyl groups. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ee displays the Ce 3d orbital spectrum, revealing that Ce in the composite exists as a mixed valence state of Ce\\u0026sup3;⁺ and Ce⁴⁺. The peaks at 885.1 eV and 881.5 eV correspond to the Ce\\u0026sup3;⁺ 3d⁵/\\u0026sup2; orbital, while those at 901.9 eV and 904.2 eV belong to the Ce\\u0026sup3;⁺ 3d\\u0026sup3;/\\u0026sup2; orbital. while the binding energies at 898.9 eV and 887.2 eV correspond to the Ce⁴⁺ 3d₅/₂ orbital, and the peak at 907.2 eV belongs to the Ce⁴⁺ 3d₃/₂ orbital [\\u003cspan citationid=\\\"CR23\\\" class=\\\"CitationRef\\\"\\u003e23\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e]. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003ef shows the Ti 2p spectrum, where 458.9 eV corresponds to the Ti 2p₃/₂ binding energy and 464.5 eV to the Ti 2p₁/₂ binding energy, consistent with Ti⁴⁺ in rutile TiO₂.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec13\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.4 TEM and SEM Analysis\\u003c/h2\\u003e \\u003cp\\u003eTo investigate the morphology and microstructure of the composite materials, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations were conducted on UiO-66, UT, and UTPA materials. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ea and \\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003eb show SEM images of pristine UiO-66 and UT composite with TiO₂, respectively. The synthesized UiO-66 particles exhibit uniform distribution with an average size of 3\\u0026ndash;5 \\u0026micro;m, featuring close interfacial contact between particles, indicating high structural homogeneity of the composite. Figures\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ec and \\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ed present SEM images of UTPA (20 \\u0026micro;L, CTAB). PANI is observed to uniformly coat the UT surface, a finding corroborated by TEM images (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ee and \\u003cspan refid=\\\"Fig4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003ef). This PANI-coated UT forms a core-shell structure that not only provides an efficient channel for charge transport, enabling rapid interfacial electron transfer, but also exhibits structural stability. The polymer coating suppresses particle agglomeration. EDS mapping reveals uniform distribution of C, N, O, Ce, and Ti elements throughout the composite, with no discernible elemental clustering or segregation.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec14\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.5 BET Analysis\\u003c/h2\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eSpecific Surface Area, Pore Volume, and Pore Size Distribution of UiO-66, UT, and UTPA\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"4\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eSample\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSpecific surface area(m\\u003csup\\u003e2\\u003c/sup\\u003e/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003ePore volume(cm\\u003csup\\u003e3\\u003c/sup\\u003e/g)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eAverage crystallite\\u003c/p\\u003e \\u003cp\\u003e(nm)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eUiO-66\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e6.275 m\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.041 cm\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e3.406 nm\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eUT\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e11.480 m\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.047 cm\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e3.814 nm\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eUTPA\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e20.245 m\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0.178 cm\\u003csup\\u003e2\\u003c/sup\\u003e/g\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e20.046 nm\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe specific surface area and pore size distribution of UiO-66, UT, and UTPA materials were analyzed using N₂ adsorption-desorption and Barrett-Joyner-Halenda (BJH) techniques. As shown in Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e, the composite materials with TiO₂ and PANI exhibited significantly enhanced specific surface areas, reaching 20.245 m\\u0026sup2;/g. This represents increases of 68.9% and 43.2% compared to pure UiO-66 (6.275 m\\u0026sup2;/g) and binary UT materials (11.480 m\\u0026sup2;/g), respectively. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig5\\\" class=\\\"InternalRef\\\"\\u003e5\\u003c/span\\u003e displays the N₂ adsorption-desorption isotherms for the three materials. Within the relative pressure range (P/P₀) of 0\\u0026ndash;1.0, all three materials exhibit Type IV isotherms with distinct H₃ hysteresis loops, confirming their mesoporous structures [\\u003cspan citationid=\\\"CR25\\\" class=\\\"CitationRef\\\"\\u003e25\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR26\\\" class=\\\"CitationRef\\\"\\u003e26\\u003c/span\\u003e]. The combination of high specific surface area and mesoporous structure enhances dye adsorption on the composite materials. This increases the number of active sites on the surface while shortening the distance for photo-generated electrons and holes to transfer to the sample. It also partially suppresses the recombination of photo-generated carriers, thereby enhancing the redox reaction efficiency and improving photocatalytic activity.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec15\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.6 UV-vis DRS Analysis\\u003c/h2\\u003e \\u003cp\\u003eIn order to explore the light absorption properties of the composites, UV-vis DRS test was carried out. In Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig6\\\" class=\\\"InternalRef\\\"\\u003e6\\u003c/span\\u003e (a), TiO\\u003csub\\u003e2\\u003c/sub\\u003e only has a strong absorption in the ultraviolet region. Compared with TiO\\u003csub\\u003e2\\u003c/sub\\u003e, the light absorption of UT composites is extended from the ultraviolet region to the visible region, but there is no significant change in the light absorption range compared with UiO-66. In Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig6\\\" class=\\\"InternalRef\\\"\\u003e6\\u003c/span\\u003e (b), the light absorption of the binary material UT was significantly enhanced in the visible region after compounding with PANI, indicating that PANI effectively enhanced the light absorption performance of the composite.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe band gap Eg of the semiconductor can be estimated according to the Tauc equation: (αhν)\\u003csup\\u003en\\u003c/sup\\u003e=B(hν-Eg), where α is the absorption coefficient, h is the Planck constant, n is 2 or 1/2 depending on the type of semiconductor and the electronic transition properties, ν is the optical frequency, B is the proportional constant, Eg is the band gap energy, if the material is a direct semiconductor: n\\u0026thinsp;=\\u0026thinsp;1/2, indirect semiconductor: n\\u0026thinsp;=\\u0026thinsp;2. The tangent line is drawn by the relationship change diagram and intersects with the x-axis, and the intersection point is the band gap Eg of the material. It can be seen from Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig7\\\" class=\\\"InternalRef\\\"\\u003e7\\u003c/span\\u003e that the band gap of single UiO-66 is 1.81 eV, the band gap of TiO\\u003csub\\u003e2\\u003c/sub\\u003e is 3.00 eV, and the band gap of UT, PANI and UTPA is 1.75 eV, 2.06 eV and 1.24 eV, respectively. Compared with UiO-66, the band gap of UT composite does not change much, which may be attributed to the poor matching of the band structure between the two materials. The band gap of UTPA is significantly reduced compared with the single UiO-66 and UT materials. The reduction of the band gap enhances the response of the material to visible light, which makes the photocatalytic performance of the composite material significantly improved.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec16\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.7 Electrochemical Performance Analysis\\u003c/h2\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eElectrochemical impedance spectroscopy was employed to investigate the charge transfer kinetics of a series of composite materials. As shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig8\\\" class=\\\"InternalRef\\\"\\u003e8\\u003c/span\\u003e(a), compared to pure UiO-66, UT, and PANI, the UTPA composite exhibited the smallest impedance arc radius, indicating the lowest resistance during charge transfer and the best electron transfer capability and charge transfer rate. This is attributed to the increased specific surface area of the composite material through the incorporation of PANI, which generates additional electron transfer pathways, thereby enhancing the heterogeneous electron transfer process [\\u003cspan citationid=\\\"CR27\\\" class=\\\"CitationRef\\\"\\u003e27\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eTo further validate charge separation efficiency, transient photocurrent responses were recorded under intermittent UV illumination (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig8\\\" class=\\\"InternalRef\\\"\\u003e8\\u003c/span\\u003eb). The UTPA composite exhibited the highest photocurrent density. The rapid photocurrent generation and stability during multiple switching cycles confirm the composite's ability to sustain highly efficient charge separation.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec17\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003e3.8 Photocatalytic Properties\\u003c/h2\\u003e \\u003cp\\u003eDuring the preparation of composite materials, various types of surfactants were incorporated to investigate their effects on photocatalytic performance (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig9\\\" class=\\\"InternalRef\\\"\\u003e9\\u003c/span\\u003ea). Cationic surfactant (CTAB), anionic surfactant (SDS), nonionic surfactant (PVP), and a control without surfactant were added, respectively. The UTPA composite without any surfactant showed significantly lower RhB degradation efficiency at 60 min compared to those with surfactants. Among the three surfactant-amended composites, the CTAB-amended composite exhibited the highest RhB degradation rate, reaching 99.90% at 60 min and 99.95% at 75 min. This may be attributed to surfactants enhancing dye adsorption on the material surface. As a cationic surfactant, CTAB forms micelles on the surface, promoting compact polymerization of PANI. This increases the transfer rate of photogenerated carriers during photocatalysis, thereby accelerating the photocatalytic degradation of RhB [\\u003cspan citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eTo investigate the effect of different aniline concentrations on photocatalytic performance, ternary composite materials with varying aniline concentrations were prepared for comparison (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig9\\\" class=\\\"InternalRef\\\"\\u003e9\\u003c/span\\u003eb). As shown in the figure, pure PANI exhibited the lowest degradation efficiency for RhB. With increasing aniline concentration, the degradation efficiency of the composites first increased and then decreased. The composite containing 20 \\u0026micro;L of aniline demonstrated the highest degradation efficiency, achieving a higher degradation rate than other samples under identical conditions. This indicates that the optimal aniline content effectively facilitates charge separation and increases contact area with pollutants, thereby enhancing photocatalytic activity. Conversely, excessively high aniline concentrations may cover active sites on the material surface, hindering effective contact between the dye and catalyst and consequently reducing photocatalytic efficiency [\\u003cspan citationid=\\\"CR29\\\" class=\\\"CitationRef\\\"\\u003e29\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eThe photocatalytic degradation effects of TiO\\u003csub\\u003e2\\u003c/sub\\u003e, UiO-66, UT, UTPA (20 \\u0026micro;L, CTAB ) and without catalyst were compared under the same conditions (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig9\\\" class=\\\"InternalRef\\\"\\u003e9\\u003c/span\\u003ec). The self-degradation of RhB under ultraviolet light without catalyst can be ignored (\\u0026lt;\\u0026thinsp;10%). The degradation efficiency of RhB by single UiO-66 is the slowest, and the degradation rate is 77.04% under ultraviolet light for 60 min. The degradation rate of single TiO\\u003csub\\u003e2\\u003c/sub\\u003e is 78.04% at 60 min. The degradation efficiency of RhB by binary composite UT is 95.11% at 60 min. The degradation rate of RhB by UTPA composite is the most significant, and the degradation rate is 99.90% at 60 min under the same conditions. This indicates that the UiO-66 material significantly improves its photocatalytic performance after compounding with TiO\\u003csub\\u003e2\\u003c/sub\\u003e and PANI. The UV-visible absorption spectrum (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig10\\\" class=\\\"InternalRef\\\"\\u003e10\\u003c/span\\u003ed) showed that the characteristic peak of RhB (555nm ) gradually decreased with time, confirming the efficient mineralization of the dye and no intermediate product accumulation.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eKinetics fitting of composite materials prepared under different conditions (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig10\\\" class=\\\"InternalRef\\\"\\u003e10\\u003c/span\\u003ea,b) reveals that a series of materials exhibit quasi-first-order kinetics for photocatalytic degradation of RhB, described by the model ln(C\\u003csub\\u003e0\\u003c/sub\\u003e/C)\\u0026thinsp;=\\u0026thinsp;kt, where k is the kinetic rate constant, t is the reaction time, C\\u003csub\\u003e0\\u003c/sub\\u003e is the initial concentration of RhB, and C is the concentration of RhB at time t. The composite incorporating 20 \\u0026micro;L aniline and utilizing CTAB as the surfactant exhibited the highest rate constant (k\\u0026thinsp;=\\u0026thinsp;0.0939 min⁻\\u0026sup1;), which is 3.51 times that of the pristine UiO-66 material (k\\u0026thinsp;=\\u0026thinsp;0.0267 min⁻\\u0026sup1;) and 2.18 times that of the binary UT composite (k\\u0026thinsp;=\\u0026thinsp;0.043 min⁻\\u0026sup1;). This indicates that compositing with TiO₂ and PANI effectively enhances the photocatalytic degradation performance of Ce-based UiO-66 materials.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eIn order to evaluate the reusability of the composites, continuous cyclic degradation tests were performed on the UTPA material under the same experimental conditions (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig11\\\" class=\\\"InternalRef\\\"\\u003e11\\u003c/span\\u003e). After each degradation, the catalyst was recovered by centrifugation and washed with deionized water and anhydrous ethanol alternately. After drying, it was put into the next round of use. After 5 cycles, the UTPA composite still showed high photocatalytic activity, indicating that the material had good structural stability and less photocorrosion during photocatalytic degradation. The main reason for the decrease in efficiency is the inevitable physical mass loss in the centrifugal recovery process, rather than the deactivation of the material itself.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eTo investigate the roles of various active substances in the photocatalytic degradation of RhB, different types of radical scavengers were introduced into the catalytic system. Under identical experimental conditions, L-ascorbic acid, tert-butanol, and EDTA-2Na were selected as scavengers for superoxide radicals (\\u0026bull;O₂⁻), \\u0026bull;OH radical, and active hole (h⁺) scavengers, respectively. The photocatalyst used was the sample UTPA (20 \\u0026micro;L/CTAB). As shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig12\\\" class=\\\"InternalRef\\\"\\u003e12\\u003c/span\\u003e, the addition of L-ascorbic acid exhibited the most significant inhibitory effect on RhB degradation efficiency, reducing it from 99.90% to 52.97% within 60 min. This result indicates that \\u0026bull;O₂⁻ is the primary active species responsible for RhB oxidation.\\u003c/p\\u003e \\u003cp\\u003eTo further elucidate the mechanism of photocatalytic degradation of RhB by UTPA materials and the structure of their heterojunction, Mott-Schottky measurements were performed on UiO-66, TiO₂, and PANI. These were combined with UV-vis DRS measurements to calculate their conduction band potential and valence band potential. Mott-Schottky measurements primarily assess the flat-band potential and charge carrier density. As shown in Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig13\\\" class=\\\"InternalRef\\\"\\u003e13\\u003c/span\\u003e, the positive slope of the UiO-66 and TiO₂ curves indicates n-type semiconductor behavior, while the negative slope of the PANI curve signifies p-type semiconductor behavior. The flat-band potential of semiconductor materials can be roughly calculated from the x-intercept of the linear region in the Mott-Schottky curve. The flat-band potential of UiO-66 is -1.11 eV. Since the conduction band potential of an n-type semiconductor is 0.1 eV more negative than the flat-band potential, the CB potential of UiO-66 is -1.21 eV. Based on the relationship between the Normalized Hydrogen Electrode (NHE) and the Ag/AgCl electrode, E\\u003csub\\u003eNHE\\u003c/sub\\u003e = E\\u003csub\\u003eAg/AgCl\\u003c/sub\\u003e+0.197, yielding a CB potential of -1.01 eV for UiO-66. UV-vis DRS measurements indicate a bandgap of 1.81 eV for UiO-66. Using the equation Eg\\u0026thinsp;=\\u0026thinsp;VB - CB, the VB of UiO-66 is calculated as 0.80 eV. The flat-band potential of TiO₂ is -0.50 eV. Based on the above relationship, its CB is -0.40 eV, and its bandgap is 3.0 eV, thus its VB is 2.6 eV. The flat-band potential of PANI is 0.84 eV. Since the flat-band potential of a p-type semiconductor is close to its HOMO energy level, it is approximated as equal to the HOMO energy level. Thus, the HOMO energy level of PANI is 0.84 eV. The flat-band potential of a p-type semiconductor is 0.1 eV more negative than its band edge potential. The band gap of PANI is 2.06 eV. Therefore, based on calculations, the LUMO energy level of PANI is -1.12 eV.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eBased on the above characterization and analysis, the possible mechanism for photocatalytic degradation of RhB by the UTPA composite material is discussed and inferred. Based on the energy level arrangement of the three components and the results of radical scavenging experiments, it is inferred that the UTPA composite forms a ternary synergistic Z-type heterojunction system [\\u003cspan citationid=\\\"CR30\\\" class=\\\"CitationRef\\\"\\u003e30\\u003c/span\\u003e]. In this system, PANI, as the organic conductive polymer, acts as the charge transport medium. The specific mechanism is as follows: Under UV irradiation, UiO-66 and TiO₂ are simultaneously excited, generating electron-hole pairs. Electrons on the TiO₂ CB transfer through PANI to the UiO-66 VB, where they recombine with holes. This spatially separates charge carriers, with PANI serving as the electron transfer pathway. Its conjugated structure and matched LUMO/HOMO levels enable directed carrier recombination, broadening the light absorption range and accelerating charge transfer. Electrons accumulate on the CB of UiO-66, whose CB potential of -1.01 eV is more negative than the standard reduction potential of O₂/\\u0026bull;O₂⁻ (-0.33 eV vs NHE). Consequently, electrons enriched on the UiO-66 CB react with adsorbed oxygen (O₂) to generate superoxide radicals (\\u0026bull;O₂⁻) with strong oxidizing capabilities [\\u003cspan citationid=\\\"CR31\\\" class=\\\"CitationRef\\\"\\u003e31\\u003c/span\\u003e], cleaving the RhB dye molecules to yield CO₂ and H₂O ultimately. Figure\\u0026nbsp;\\u003cspan refid=\\\"Fig14\\\" class=\\\"InternalRef\\\"\\u003e14\\u003c/span\\u003e illustrates this process.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"4. Conclusions\",\"content\":\"\\u003cp\\u003eCe-UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e was successfully synthesized by oil bath method. TiO\\u003csub\\u003e2\\u003c/sub\\u003e was successfully introduced on the basis of Ce-UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e, and binary UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e/TiO\\u003csub\\u003e2\\u003c/sub\\u003e(UT)composites were constructed. On the basis of binary UT materials, polyaniline (PANI) was introduced by in-situ oxidation polymerization, and UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e/TiO\\u003csub\\u003e2\\u003c/sub\\u003e/PANI (UTPA) ternary composites were successfully prepared. The characterization results show that PANI is uniformly coated on the surface of UT, and a good interfacial interaction is formed between the three. The introduction of appropriate amount of PANI increases the specific surface area of the composite material, enhances the visible light absorption capacity, and significantly promotes the separation and transmission of photogenerated carriers. Photocatalytic degradation experiments showed that the degradation rate of RhB by UTPA was more than 99.9% in 60 min, which was significantly better than that of single component and UT binary material. Free radical capture experiments showed that superoxide radicals (\\u0026middot;O\\u003csub\\u003e2\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e) were the main active species in the reaction system. Combined with the analysis of energy band structure, the photocatalytic enhancement mechanism of UTPA ternary heterojunction was proposed.The cyclic stability test confirmed that the composite material had good reusability.\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\" \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Funding\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Competing interests\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe authors declare no competing financial interests or personal relationships that could influence this work.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Ethics approval and consent to participate\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003eNot applicable.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Consent for publication\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003eAll authors have read and approved the final manuscript for publication.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Availability of data and materials\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe datasets generated and analyzed during this study are available from the corresponding author upon reasonable request.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003e\\u0026bull; Data Availability Statement\\u003c/b\\u003e \\u003c/p\\u003e \\u003cp\\u003eThe authors declare that the data supporting the findings of this study are available within the paper. Should any raw data files be needed in another format, they are available from the corresponding author upon reasonable request. Source data are provided with this paper.\\u003c/p\\u003e\\u003ch2\\u003eAuthor Contribution\\u003c/h2\\u003e\\u003cp\\u003eLili Li wrote the main manuscript.Jiaxin Li prepared figures 1-4.Yuyu Ma prepared figures 6-10Jing Shu reviewed the manuscript.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\u003cli\\u003e\\u003cspan\\u003eZhang, X., Wang, J., Dong, X.X., et al.: Functionalized metal-organic framewo-rks for photocatalytic degradation of organic pollutants in the environment. Chemosphere(2020). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.chemosphere.2019.125144\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.chemosphere.2019.125144\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMunien, C., Rathilal, S., Tetteh, E.K.: Challenges and Prospects of TiO\\u003csub\\u003e2\\u003c/sub\\u003e-Based Photocatalysis for Wastewater Treatment: Keyword Analysis. Catalysts (2025). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.3390/catal15090801\\u003c/span\\u003e\\u003cspan address=\\\"10.3390/catal15090801\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eSabzehmeidani, M.M., Karimi, H., Ghaedi, M.: CeO\\u003csub\\u003e2\\u003c/sub\\u003e nanofibers-CdS nanostruc-tures n\\u0026ndash;n junction with enhanced visible-light photocatalytic activity. Arab. J. Chem. \\u003cb\\u003e13\\u003c/b\\u003e, 7583\\u0026ndash;7597 (2020)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eBanyal, R., Sonu, S., Soni, V., et al.: Synergetic photocatalytic degradation of the tetracycline antibiotic over S-scheme-based BiOBr/CuInS\\u003csub\\u003e2\\u003c/sub\\u003e/WO\\u003csub\\u003e3\\u003c/sub\\u003e ternary heterojunction photocatalyst. Solid State Sci. (2024). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.solidstatesciences.2024.107700\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.solidstatesciences.2024.107700\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eRana, A., Sonu, S., Soni, V., et al.: Novel S-scheme derived Mo\\u0026ndash;Bi\\u003csub\\u003e2\\u003c/sub\\u003eWO\\u003csub\\u003e6\\u003c/sub\\u003e/WO\\u003csub\\u003e3\\u003c/sub\\u003e/Biochar composite for photocatalytic removal of Methylene Blue dye. J. Phys. Chem. Solids. (2025). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.jpcs.2024.112385\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.jpcs.2024.112385\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eCheng, L., Xiang, Q.J., Liao, Y.L., et al.: CdS-based photocatalysts. Energy Environ. Sci. \\u003cb\\u003e11\\u003c/b\\u003e, 1362\\u0026ndash;1391 (2018)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMa, R., Zhang, S., Wen, T., et al.: A critical review on visible-light-response CeO\\u003csub\\u003e2\\u003c/sub\\u003e-based photocatalysts with enhanced photooxidation of organic pollutants. Catal. Today. (2019). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.cattod.2018.11.016\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.cattod.2018.11.016\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eOng, C.B., Ng, L.Y., Mohammad, A.W.: A review of ZnO nanoparticles as so-lar photocatalysts: synthesis, mechanisms and applications. Renewable and S-ustainable Energy Reviews (2018). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.rser.2017.08.020\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.rser.2017.08.020\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLi, Y.F., Xia, Z.L., Yang, Q., et al.: Review on g-C\\u003csub\\u003e3\\u003c/sub\\u003eN\\u003csub\\u003e4\\u003c/sub\\u003e-based S-scheme hetero-junction photocatalysts. J. Mater. Sci. Technol. \\u003cb\\u003e125\\u003c/b\\u003e, 128\\u0026ndash;144 (2022)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eZhou, H.C., Long, J.R., Yaghi, O.M.: Introduction to metal\\u0026ndash;organic frameworks. Chem. Rev. \\u003cb\\u003e112\\u003c/b\\u003e(2), 673\\u0026ndash;674 (2012)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eParnicka, P., Lisowski, W., Klimczuk, T., et al.: A novel (Ti/Ce)UiO-X MOFs@TiO\\u003csub\\u003e2\\u003c/sub\\u003e heterojunction for enhanced photocatalytic performance: Boosting via Ce\\u003csup\\u003e4+\\u003c/sup\\u003e/Ce\\u003csup\\u003e3+\\u003c/sup\\u003e and Ti\\u003csup\\u003e4+\\u003c/sup\\u003e/Ti\\u003csup\\u003e3+\\u003c/sup\\u003e redox mediators. Appl. Catal. B. (2022). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.apcatb.2022.121349\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.apcatb.2022.121349\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLiang, R., Jing, F., Shen, L., et al.: M@ MIL-100 (Fe)(M\\u0026thinsp;=\\u0026thinsp;Au, Pd, Pt) nanocomposites fabricated by a facile photodeposition process: Efficient visible-lig-ht photocatalysts for redox reactions in water. Nano Res. \\u003cb\\u003e8\\u003c/b\\u003e, 3237\\u0026ndash;3249 (2015)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLiu, X., Dang, R., Dong, X.J., et al.: A sandwich-like heterostructure of TiO\\u003csub\\u003e2\\u003c/sub\\u003e nanosheets with MIL-100 (Fe): a platform for efficient visible-light-driven photocatalysis. Appl. Catal. B. \\u003cb\\u003e209\\u003c/b\\u003e, 506\\u0026ndash;513 (2017)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLai, Y.X., Wang, F., Zhang, Y.M., et al.: UiO-66 derived N-doped carbon na-noparticles coated by PANI for simultaneous adsorption and reduction of hexavalent chromium from waste water. Chem. Eng. J. (2019). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.cej.2019.122069\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.cej.2019.122069\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eXue, Y.M., Lin, J., Fan, Y., et al.: Controllable synthesis of uniformly distri-buted hollow rutile TiO\\u003csub\\u003e2\\u003c/sub\\u003e hierarchical microspheres and their improved photoc-atalysis. Mater. Chem. Phys. (2013). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.matchemphys.2013.09.026\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.matchemphys.2013.09.026\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGhamim, E.E., Walker, M., Walton., R.I.: Rapid synthesis of cerium-UiO-66 MOF nanoparticles for photocatalytic dye degradation. Dalton Trans. \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1039/d3dt00890h\\u003c/span\\u003e\\u003cspan address=\\\"10.1039/d3dt00890h\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eNosrati, R., Olad, A., Najjari, H.: Study of the effect of TiO\\u003csub\\u003e2\\u003c/sub\\u003e/polyaniline nan-ocomposite on the self-cleaning property of polyacrylic latex coating.Surface and Coatings Technology. \\u003cb\\u003e316\\u003c/b\\u003e: 199\\u0026ndash;209 (2017)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eWu, J.F., Fang, X.X., Zhu, Y.Z., et al.: Well-Designed TiO\\u003csub\\u003e2\\u003c/sub\\u003e@UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e Na-nocomposite with Superior Photocatalytic Activity for Tetracycline under Restricted Space. Energy Fuels. \\u003cb\\u003e34\\u003c/b\\u003e, 12911\\u0026ndash;12917 (2020)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eAiri, A., Atzori, C., Bonino, F., et al.: A spectroscopic and computational stu-dy of a tough MOF with a fragile linker: Ce-UiO-66-ADC. Dalton Transactions (2020). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1039/c9dt04112e\\u003c/span\\u003e\\u003cspan address=\\\"10.1039/c9dt04112e\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eHadjiivanov, K.I., Panayotov, D.A., Mihaylov, M.Y., et al.: Power of infrared and Raman spectroscopies to characterize metal-organic frameworks and inv-estigate their interaction with guest molecules.Chemical Reviews (2020). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1021/acs.chemrev.0c00487\\u003c/span\\u003e\\u003cspan address=\\\"10.1021/acs.chemrev.0c00487\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGao, J.T., Wang, Y., Zhou, S.J., et al.: A Facile One-Step Synthesis of Fe‐D-oped g‐C\\u003csub\\u003e3\\u003c/sub\\u003eN\\u003csub\\u003e4\\u003c/sub\\u003e Nanosheets and Their Improved Visible‐Light Photocatalytic Pe-rformance. ChemCatChem. \\u003cb\\u003e9\\u003c/b\\u003e(9), 1708\\u0026ndash;1715 (2017)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eXu, Y.G., Ge, F.Y., Chen, Z.G., et al.: One-step synthesis of Fe-doped surface-alkalinized g-C\\u003csub\\u003e3\\u003c/sub\\u003eN\\u003csub\\u003e4\\u003c/sub\\u003e and their improved visible-light photocatalytic performance. Appl. Surf. Sci. \\u003cb\\u003e469\\u003c/b\\u003e, 739\\u0026ndash;746 (2019)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003ePaparazzo, E.: Use and misuse of X-ray photoemission spectroscopy: Ce3d s-pectra of Ce\\u003csub\\u003e2\\u003c/sub\\u003eO\\u003csub\\u003e3\\u003c/sub\\u003e and CeO\\u003csub\\u003e2\\u003c/sub\\u003e. J. Phys.: Condens. Matter. (2019). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1088/1361-648X/aad248\\u003c/span\\u003e\\u003cspan address=\\\"10.1088/1361-648X/aad248\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003ePfau, A., Schierbaum, K.D.: The electronic structure of stoichiometric and reduced CeO\\u003csub\\u003e2\\u003c/sub\\u003e surfaces: an XPS, UPS and HREELS study. Surf. Sci. \\u003cb\\u003e321\\u003c/b\\u003e, 71\\u0026ndash;80 (1994)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMitra, M., Ahamed, S.T., Ghost, A., et al.: Polyaniline/reduced graphene oxide composite-enhanced visible-light-driven photocatalytic activity for the degradation of organic dyes. ACS Omega. (2019). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://pubs.acs.org/doi/\\u003c/span\\u003e\\u003cspan address=\\\"https://pubs.acs.org/doi/\\\" targettype=\\\"URL\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003e10.1021/acsomega.8b02941\\u003c/span\\u003e\\u003cspan address=\\\"10.1021/acsomega.8b02941\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eGilja, V., Vrban, I., Mandić, V., et al.: Preparation of a PANI/ZnO composit-e for efficient photocatalytic degradation of acid blue. Polymers. (2018). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.3390/polym10090940\\u003c/span\\u003e\\u003cspan address=\\\"10.3390/polym10090940\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eYang, Z.L., Peng, D.Y., Zeng, H.Y., et al.: Enhanced photocatalytic performance of heterostructure BiOBr/PPy for Cr(VI) reduction and dye degradation. Colloids Surf. A: Physicochem Eng. Aspects. (2024). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.colsurfa.2023.132647\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.colsurfa.2023.132647\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eWu, W.Z., Zhang, L.J., Zhai, X.J., et al.: Preparation and photocatalytic acti-vity analysis of nanometer TiO\\u003csub\\u003e2\\u003c/sub\\u003e modified by surfactant. Nanomaterials Nanatechnol. \\u003cb\\u003e8\\u003c/b\\u003e, 1\\u0026ndash;8 (2018)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eLiu, L., Ding, L., Liu, Y.G., et al.: A stable Ag\\u003csub\\u003e3\\u003c/sub\\u003ePO\\u003csub\\u003e4\\u003c/sub\\u003e@PANI core@shell hybr-id: Enrichment photocatalytic degradation with π-π conjugation. Appl. Catal. B. \\u003cb\\u003e201\\u003c/b\\u003e, 92\\u0026ndash;104 (2016)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eSin, J.C., Lam, S.M., Zeng, H.H., et al.: Design and synthesis of Fe\\u003csub\\u003e2\\u003c/sub\\u003eWO\\u003csub\\u003e6\\u003c/sub\\u003e/ Eu-doped BiOBr nanocomposite: A novel 0D/2D Z-scheme heterojunction sy-stem for simultaneous boosted visible-light driven photocatalytic bisphenol A degradation and Cr(VI) reduction. Ceram. Int. \\u003cb\\u003e50\\u003c/b\\u003e, 5372\\u0026ndash;5383 (2024)\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eXu, H., Dai, J.C., Fang, K.J., et al.: BiOI/PPy/cotton photocatalytic fabric for efficient organic dye contaminant degradation and self-cleaning application. Colloids Surf., A. (2023). \\u003cspan class=\\\"ExternalRef\\\"\\u003e\\u003cspan class=\\\"RefSource\\\"\\u003ehttps://doi.org/10.1016/j.colsurfa.2023.131862\\u003c/span\\u003e\\u003cspan address=\\\"10.1016/j.colsurfa.2023.131862\\\" targettype=\\\"DOI\\\" class=\\\"RefTarget\\\"\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/span\\u003e\\u003c/li\\u003e\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Photocatalysis, Ce-UiO-66-NH₂, TiO₂, PANI, Type-Zheterojunction\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-9454538/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-9454538/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eThe Ce-UiO-66-NH\\u003csub\\u003e2\\u003c/sub\\u003e material was successfully prepared by oil bath method, and TiO\\u003csub\\u003e2\\u003c/sub\\u003e and PANI were compounded on the basis of it, which improved the degradation efficiency of rhodamine B ( RhB ). XRD, TEM and XPS characterization confirmed that the composite material formed a core-shell structure and polyaniline was uniformly coated. The composite with 20\\u0026micro;L aniline and CTAB surfactant showed the highest degradation efficiency, and the degradation rate of RhB reached 99.90% within 60 min under ultraviolet light irradiation. The band alignment and free radical trapping experiments show that it follows the ternary Z-type heterojunction mechanism, \\u0026bull;O\\u003csub\\u003e2\\u003c/sub\\u003e\\u003csup\\u003e\\u0026minus;\\u003c/sup\\u003e is the main active species. It provides a new idea for the design of high-performance photocatalysts and is of great significance for promoting the application of photocatalytic technology in water pollution control.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Preparation of Ce-UiO-66-NH₂/TiO₂/PANI Composite and Photocatalytic Degradation of RhB\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-05-11 09:02:55\",\"doi\":\"10.21203/rs.3.rs-9454538/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"d52ca3c7-5aa0-4512-b715-4ffbf231a710\",\"owner\":[],\"postedDate\":\"May 11th, 2026\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-05-11T09:02:58+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2026-05-11 09:02:55\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-9454538\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-9454538\",\"identity\":\"rs-9454538\",\"version\":[\"v1\"]},\"buildId\":\"XKTyCvWXoU3ODBz1xrDgd\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}