Composite of graphene oxide from rice husks with copper nanoparticles immobilized: synthesis and application in catalytic dye degradation

Composite of graphene oxide from rice husks with copper nanoparticles immobilized: synthesis and application in catalytic dye degradation | 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 Composite of graphene oxide from rice husks with copper nanoparticles immobilized: synthesis and application in catalytic dye degradation Elsy Bastidas, Maria Rodriguez, Jimmy Castillo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4461351/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 Graphene and its derivatives, such as graphene oxide, have a wide range of applications in industry, especially in electronics, electrode construction, catalyst in electro- and photocatalytic reactions, etc. This work presents results from the synthesis of graphene oxide sheets (GOs) from rice husks ash and its modification by incorporating copper nanoparticles. Rice husks, a low-value waste product generated in large quantities, were thermally treated to obtain a mixture of natural carbons with silica. This carbonaceous material was then reacted with potassium hydroxide to produce GOs. The GOs were modified using an impregnation and reduction process to immobilize copper metal nanoparticles onto their surface and obtain graphene oxide with CuO nanoparticles in their surface (GOs-CuO). The synthesized composites were characterized by FTIR, SEM, BET, XRD, and AFM, demonstrating that the formed structure is composed of graphene with predominantly copper oxide nanoparticles adsorbed on its surface. The band gap for the synthesized structures was determined by finding a significant decrease in the band gap of graphene oxide when copper nanoparticles are incorporated. Catalytic capacities of synthetized samples were tested in the decomposition reaction of pollutants, using Rhodamine B (RhB) as a model molecule due to its environmental persistence and toxicity. Both GOs and GOs-CuO effectively degraded RhB, with GOs-CuO demonstrating a 8-fold faster kinetic rate, highlighting its potential for pollutant remediation applications. Graphene from biomass Graphene catalytic reduction Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction The use of biomass from different sources such as corn, coconut[ 1 – 5 ], rice[ 6 – 8 ], etc. has been reported as source of products of valuable interest, in special in energy generation. In particular, rice husks calcination have been used as a source of energy, and for the production of materials such as silica, activated carbon and graphene[ 2 , 9 ]. Rice husks have a 18% of silica and can be extracted through various physical or chemical processes to produce high-quality materials such as nanometric-sized silica, silicon, etc. Rice husks calcinated a 400 C, generate a carbonaceous material that can be transformed in graphene, and graphene oxide[ 2 , 3 , 10 ]. Characterization of nanomaterials and particularly, graphene-derived materials, is essential to understand their potential applications. Techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectroscopy, and infrared absorption spectroscopy are used to precisely analyze these materials’ structural properties, shape, size, and composition[ 3 , 11 ]. Graphene’s unique qualities, including its exceptional electrical conductivity, low thermal conductivity, and high affinity for hydrophobic compounds, make it a highly sought-after material. Products derived from graphene, such oxidized graphene[ 12 – 15 ], have a very particular attraction since they allow maintaining intrinsic properties of the spatial arrangement of graphene sheets with special modifications that allow them to expand their application capacity. Utilizing advanced characterization techniques, including SEM, AFM, Uv-visible and infrared absorption spectroscopy, to gain a comprehensive understanding of the properties and structure of these versatile materials is essential for optimizing their synthesis and modification for integration into the latest technological innovations. One of the novelties of the process we are presenting is that it can obtain graphene oxide without the use of corrosive and highly polluting compounds like those employed by traditional methods, leading to simpler reactions. Graphene has been used as an adsorbent in the treatment of water contaminated with dyes, pesticides[ 16 – 19 ], etc., showing great effectiveness because of its large active surface area. The dye degradation process can be mediated by its oxidation or reduction in order to change from water insoluble to soluble. The products from reaction process are more easily for handle and disposal[ 20 , 21 ]. If the dimensions of the graphene sheets are reduced, materials with greater adsorbency efficiency are obtained. Copper in the zero-valent state functions as a catalyst in electrocalalitic and photo-catalytic reactions, since it allows modifications in conductivity band by interaction with the substrate and allows higher efficiency, reaction speed, and lower energy consumption in the reactions. Nanometric copper[ 22 – 25 ] has been tested as an electrocatalyst, showing higher efficiency than copper at macroscopic sizes. New materials, using a mixture of graphene and copper[ 26 – 28 ] has been allowed the development of electrocatalytic materials usefully in the treatment of water contaminated with dyes and pesticides[ 29 , 30 ]. This work present the results of producing graphene oxide sheets (GOs) from rice husks with a easy an low reagent consuming methodology. The GOs is used as a support for copper oxide nanoparticles produced from the reduction of ionic copper adsorbed onto graphene sheets. The material is used as catalyst for the decomposition reaction of rhodamine B. The results of the characterization evidence the formation of copper nanoparticles on the surface of oxidized graphene with sizes of approximately 20 nm in size supported on micrometer sheets composed of 2 or 3 sheets. The GOs-CuO prove to be a good catalyst in rhodamine B degradation reaction. 2. Materials and Methods 2.1. Materials Rice husk were provided by a local supplier. Potassium hydroxide (KOH) at 99% purity, Copper sulphate at 99% purity from sigma Aldrich and hydrochloric acid (HCl) 36%, Ascorbic Acid 99% purity and ethanol ( C 2 H 5 OH ) HPLC grade from Merck were used. 2.2. Graphene Oxide and Graphene Oxide-Copper synthesis The synthesis process for graphene from rice husks was performed with variations of the methodology reported by Muramatsu et all[ 30 ]. In short, 100 gr of rice husks are washed with hydrochloridric acid 1 M and rinsed with distilled water. The clean rice husks are heated in air furnace at 400°C for 2 hours to calcine all the organic matter (cellulose, lignins, etc.). The solid residue obtained composed by carbon and silica is called rice husk ash. (RHA). The RHA is then mixed with solid KOH with a 2:1 proportion. The mixture is placed in a larger crucible and cover with a ceramic dish, them, the deposit is filled with rice husks twice the height of the small crucible to diminish contact with air and prevent oxidation of the mixture in the small pot. The system is heated at 800 ° C for 2 hours. The result mixture was rinsed with distilled water until pH 7, to remove the residue of potassium salts. The solid was separated by centrifugation at 3200 revolutions per minute (RPM) for 30 minutes and then dried in an oven for 24 hours at 80 ° C, partially oxidized graphene (GpO) is obtained. Graphene-Copper (GpO-Cu) is prepared by mixing the previous synthetize graphene with Copper sulphate followed by reduction with 1M ascorbic acid in pH 8 media. The material obtained is then evaluated using contact angle measurement, UV-vis and FTIR absorption spectroscopy, atomic force microscopy, dynamic light scattering, and scanning electron microscopy. 2.3. Catalytic reduction methodology Rhodamine B (RhB) dye was used to evaluate the catalytic abilities of the prepared samples. For the catalytic reactions, 2.0 mL of 0.01 mM the RhB dye and 200 µ L of 0.4 M freshly prepared NaBH 4 were mixed. The degradation efficiency was monitored using an ultraviolet (UV)-visible spectrometer (Neogen). Blank control experiments were performed without catalyst, Two 0.4 mg of different catalyzers were used, GpO and GpO-Cu. 2.4. Material Characterization GpO and the composite GpO-Cu morphology were confirmed by SEM using a Jeol JSM-6399 and AFM using a Bruker Dimension Edge. AFM measurements were performed in tapping mode with a silicon tip. The samples were supported in the sample holder by dispersing a minimum amount of material on a flat silicon surface. The chemical composition of all the materials were studied by FT Infrared spectroscopy using a Bruker FT-IR spectrometer. The UV-Vis spectra were measured with Ocean Optics spectrometer and the spectra were used to calculate variations in the Band-Gap. Composition and size were determined by XRD spectra were measured in Bruker D2 phaser. 3. Results and Discussion The SEM image analysis (Fig. 1 ), provides valuable information about the structure and composition of the graphene oxide sheets modified with copper nanoparticles. The image on (1 left) shows the graphene sheets after being modified with copper nanoparticles, with GpO sheets with sizes in the order of microns and small semi-transparent pieces on their surface, the EDX analysis and element composition.The presence of the bright spots in image (right) indicates the successful deposition of copper nanoparticles on the graphene oxide sheets, and the high density of these spots suggests a strong interaction between the copper nanoparticles and the graphene structure. This information is important for understanding the properties and potential applications of these GpO-Cu composites. Additionally, the EDX analysis confirms the presence of copper nanoparticles on the graphene oxide sheets. Overall, this SEM image analysis and EDX analysis provide valuable insights into the structure and composition of the GpO-Cu composites. 3.1 AFM and Scanning Electron Microscopy Figure 2 shown the AFM image of GpO sheet (2A) and GpO with copper nanoparticles (2B), the line profile in the upper part of the images in the case of GpO shown a 2 nm thickness for the sample with few irregularities, showing a few layers composition (approximately 2 layers). In the case of the GpO-Cu the profile shown irregularities due the copper nanoparticles present in the GpO surface. The typical thickness of pure graphene sheets is approximately 0.35 nm as has been reported in previous works[ 11 ]. In the case of partially oxidized graphene the thickness of the sheets is increased due to the functional groups that are part of the structure[ 12 ], and introduce spatial irregularities in the structure, so the intersheets distances could increase to a thickness of about 1 nm. 3.2. Contact Angle The different forms of carbon can behave as hydrophilic or hydrophobic, depending on their structure and composition; in both graphite and carbon the hydrophilic character is associated with contaminants on the carbon surface[ 31 ] furthermore graphene is hydrophobic. Figure 3 shows images of a water droplet placed on a graphene surface (a) and a graphene surface with copper nanoparticles adsorbed to surface (b). It can be seen that in the case of GpO the contact angle is 124°, which confirms the degree of hydrophobicity of GpO. In the image on the right (b) shows a water drop almost completely spread on the surface of GpO-Cu with a contac angle of 7.5°, this variation in hydrophobicity due to the high content of copper nanoparticles, transforms a super hydrophobic surface in hydrophilic, due to the presence of copper nanoparticles. These materials composed of graphene and metals such as copper have applications in the processes of photoreduction and electrocatalysis, due to their conductive and catalytic properties, the ability to modify the hydrophobicity allows them to be applicable to the construction of membranes and with high efficiency in the interaction for both polar and low polarity molecules[ 29 , 32 – 34 ]. 3.3. Specific surface Area The specific surface area of graphene and its relative compounds determines many of its properties, such as adsorption capacity and conductivity. In the Fig. 4 the adsorption ratio vs relative pressure plot is presented, in the inset the pore volume as a function of pore width. The plot shown a surface area of 580 m 2 /g and a maximum pore size of 45.8 A. This specific surface area is in the range with reported in literature by Mohan et al[ 35 ], and correspond to partially oxidized graphene. BET curves of graphene with copper nanoparticles shown a similar behavior, copper nanoparticles does not decrease the adsorptive capacity of graphene significantly 3.4. Uv-Visible spectroscopy The shift in the UV-visible absorption spectra from graphite-derived to graphene oxide is a well-documented phenomenon. The peak shift from 262 nm in graphite-derived material to 230 nm in graphene oxide is indicative of the structural changes GpO. This strong absorbance band is attributed to the first π −− π ∗ transitions of aromatic C–C bonds, with the degree of oxidation determining the aromaticity of the compound. Figure 5 displays the UV-visible spectra of three compounds: Cu nanoparticles, GpO, and GpO-Cu. The extinction spectrum of the copper nanoparticles shows two maxima at 367nm and 620nm, which are typical of the surface plasmon resonance of copper nanoparticles. The spectrum of the synthesized graphene sample has a maximum at 264 nm, indicating partially oxidized graphene; the more oxidized groups present, the more red shift of the band is observed. After reaction with copper, the graphene sheets show an absorbance spectrum with a maximum at 230 nm and another at about 698 nm. This spectrum suggests that copper has been initially coordinated to the oxidized groups of graphene and used as nucleation centers for the copper ions, which upon reduction of copper merge other copper ions to form copper nanoparticles in the surface. From the UV-VIS absorbance spectrum a Tau plot is constructed. The Tauc optical bandgap is defined as the intercept Eg found from plotting: ( αhν ) (1 /n ) = A ( hν − Eg ) where α is the absorption coefficient, hν is the photon energy in electronvolts (eV), A is a constant and Eg is the optical band-gap. The parameter n is related to the nature of the optical electronic transitions, being considered 1/2 or 2 for direct and indirect transitions, respectively. The optical band-gaps from the Uv visible spectra were determined using Tauc’s plot by assuming indirect transitions. These indirect transitions were considered due to the amorphous-like character of GpO and the GpO-Cu. The mechanism for describing variations in the graphene band gap has been reported previously[ 36 – 38 ]. Briefly, graphene oxide is composed of a mixture of sp 2 and sp 3 carbons, with the latter bonded to oxygen atoms forming hydroxyl, carbonyl and epoxy groups. Each of these groups has its own energy levels that contribute together with those of the sp 2 carbons in the formation of the overall structure of the system and its band gap. Including a metal additionally on its electronic structure and its band gap contributes to the whole, modifying the band gap of the system. Calculations were performed for GpO, Cu nanoparticles and the GpO-Cu. In Fig. 6 , the Tau plot for all the samples is presented. GpO, exhibited a band gap of 3.98 eV[ 36 , 39 ], which is representative of a partially oxidized graphene with hydroxyl groups in its structure. In the case of Cu nanoparticles, the plot fit gives us a value of 3.41 eV for the band gap, which corresponds to copper nanoparticles with a low level of oxidation on their surface[ 25 ]. The reduction in band gap to 3.41 eV observed when graphene is modified with copper nanoparticles indicates improved photocatalytic characteristics. This decrease in band gap signifies a lower energy requirement for excitation and charge transfer processes, which can enhance the efficiency of photocatalytic reactions[ 40 ]. 3.5. FTIR spectroscopy The intense and broad peak at a wavelength of 3420 cm − 1 in the FTIR transmittance vs. wavelength plot confirms the presence of O-H bonds (hydroxyl groups) in the material. Additionally, the observed band at 1600 cm − 1 corresponds to the C = C stretching present in the aromatic rings of the Gp-O. Furthermore, the C-O-C stretching bands at 1226 and 1015 cm − 1 confirm the presence of epoxy groups, indicating the successful synthesis of partially oxidized graphene. During the preparation of the graphene compound with copper, copper ions are brought into contact with the graphene, these ions interact with the charged groups and then copper reduction occurs, leading to a decrease in the oxidized groups of the graphene and their substitution by copper. This is shown in the spectrum of the GpO-Cu samples. 3.6. X Ray difraction The crystallinity and structural analysis of the as synthesized copper nanoparticles was investigates by powder X–Ray diffraction technique. Figure 8 represents the diffraction pattern of Cu nanoparticles in which the peaks at 2 θ value of 43.27 and 50.38 correspond to (111), (200) planes respectively[ 22 , 40 ], confirms the cubic lattice of copper. All the diffraction peaks are in good agreement with the standard pattern for pure face centred cubic phase of copper nanoparticles (JCPDS No. 040836). The peack at 36.38 correspond to copper oxide[ 22 ], showing that the copper is partially oxidized on its surface. The calculated average size of the nanoparticles is calculated using the Scherrer equation; D = ( Kλ ) / ( βcos ( θ )). Were D is the crystalline size, K is being the shape factor, taken as 0.9, λ is the wavelength of x-ray beam of 1.541 A, β is the full-width at half-maximum of the corresponding peak, and θ is the Bragg’s diffraction angle. The peacks were fitted with seudo-voigd funtion showing an average diameter of 21.99 nm for the copper nanoparticles, this measurement results is consistent with Uv-visible data reported in literature and this paper. The band with a maximum at 2 θ = 21.59 corresponds to partially oxidized graphene. The presence of hydroxyl groups in oxidized graphene is responsible for the band shift at low 2 θ values. The layer spacing is calculated with λ = 2 dsin ( θ ) with θ the diffraction angle, from the spectra a interlayer of 0.8 nm is obtained, this value is higher than the observed for graphene pristine and this variation is due to oxidation degree in the graphene and consistent with the AFM profiles plots. 3.7. Rhodamine B catalytic degradation The rhodamine is a salt of Xantene that exhibits characteristic fluorescence due to the electron delocalization generated by the protonation of the nitrogen at position 3. In the presence of a reducing agent such as NaBH4, a hydrogen atom is transferred to C-6, resulting in the delocalization of electrons towards the tetra-nitrogen in position 3, which allows it to recover its aromaticity, with the subsequent loss of fluorescence (in the form of Leuco) as have reported previously[ 42 ]. This reaction occurs at a very slow rate. The leuco form of rhodamine is more soluble, making its disposition simpler as it does not remain adsorbed in tissues and other materials. This allows for better disposal of the residues. In the Fig. 9 the rhodamine B reduction to Leuco form. The degradation of Rhodamine B (RhB) in the presence of GpO and GpO-Cu was studied using solutions of rhodamine B in NaBNH 4 as model. The mechanism of catalytic reduction of RhB with NaBH4 in presence of catalyst involves a series of steps[ 42 ]: Step I, the reducing agent (NaBH4) transfers a hydride to the catalyst surface, leading to the formation of M-H covalent linkages; Step II, adsorption of RhB dye molecules onto the surface of the catalyst, which is rate determining step; Step III, adsorbed RhB molecules undergo reduction by capturing electrons from the active sites of catalyst along with the adsorbed H; Step IV, the reduced form of RhB i.e. LRhB desorbs from the catalyst surface leading to reactivation of catalyst for its further catalytic activity. Since, step II, adsorption of RhB over catalytic surface is rate determining step in the reduction process of former, materials as graphene oxide with high adsorptive capacity is suitable for enhance the reaction. The band-gap determines the ease and availability of free energy states for the system to allow efficient load transfer. The decrease in the band-gap of graphene by including copper in its structure allows a faster and more efficient transfer, improving the reduction process. The solution composed of RhB with a excess of NaBNH 4 is stable and show very low degradation at ambient conditions, In the experiment designed, high amounts of the reducing agent are used to ensure that it is in excess and that it is not a variable in the reaction, since the focus is on studying the effect of the catalyst. In a real exercise the amounts of the reducing agent would be limited to the minimum to avoid the formation of more contaminants. The residues produced can be removed by basic neutralization and adsorption techniques. Figure 10 shows the absorbance spectrum of a sample (a) called control composed by RhB with a excess of NaBNH 4 at different times, where it is observed that there is no change in the absorbance spectrum. For the same concentration solution with a 0.2 mg/mL of GpO, a degradation of RhB over time is observed, decreasing the absorbance significantly, the Fig. 10 B. The GpO catalyzes the degradation reaction. For the RhB sample with GpO-Cu a higher degradation is observed at shorter times as is presented in the 10C. The surface of the partially oxidized graphene acts as a catalyst, it interacts with the molecule and shares free states which decreases the energy needed for the reduction process to take place, which decisively increases the rate of the reaction. Band gap results show that in the case of partially oxidized graphene decorated with copper the band gap is smaller, which explains the acceleration of the decomposition reaction. The catalytic degradation rates of the pollutants studied have been fitted by the Langmuir-Hinshelwood (L-H) kinetic model pseudo first order and the results showed in Fig. 11 , in it is observed that in the absence of catalyst the reaction cannot be carried out at ambient conditions, due to the energy required for the change is greater than available a this conditions as is showed in the Uv-vis spectra were the signal remain constant all times. When the RhB sample is placed in the presence of GpO, a rapid degradation is observed with a constant k app = 0.1177, r 2 = 0.89 and a reduction of 40% in a time of 10 min and maximum degradation of .68%. The catalyst composed of GpO-Cu increases the reaction constant by 8 times and decreases the reaction time to 1 min for total degradation. with a constant k app = 0.821, r 2 = 0.98 and a reduction of 98% in the first 8 min. The constant of the reaction are at least 5 time faster than published for catalizers like ZnCo 2 O 4 or SnO 2 /graphene or TiO 2 /graphene[ 43 – 45 ]. Bhat et all[ 42 ] cite a complete list of results in reduction performance of different catalyst systems. expressed as k app /gr and shown values from 0.005 to 181.5 for different catalyzers and 2553.2 for a Palladium Graphene oxide catalyst. In our work a k app /gr of 34.0 was obtained, which is in the order of magnitude of the bests presented In the literature. 4. Conclusions The developed method based in utilization of carbonaceous residue from rice husks for the production of partially oxidized graphene presents an economically viable methodology for generating graphene sheets with specific functional groups. The synthesis produce a partially oxidized graphene (GpO) with unique properties. The spectroscopic data highlighting the presence of few-layered sheets with defects in their stacking pattern underscores the distinct nature of these graphene sheets, leading to notable changes in UV-visible spectra and AFM images. The subsequent modification of GpO through the addition of copper ions and their subsequent reduction results in the formation of graphene sheets with supported copper nanoparticles (GpO-Cu). The postulated process of copper ion interaction with polar groups in the oxidized graphene, serving as nucleation seeds in the reduction process and subsequent nanoparticle formation, is supported by UV-visible and FTIR spectra. The reduction in band gap observed when graphene is modified with copper nanoparticles signifies a lower energy requirement for excitation and charge transfer processes, which can enhance the efficiency of photocatalytic reactions. The catalytic potential of both GpO and GpO-Cu is evident in their ability to catalyze the decomposition reaction of RhB, with GpO-Cu exhibiting up to 8 times greater activity than GpO. This enhanced catalytic performance demonstrates the superior capabilities of these new catalysts compared to previously reported ones. Declarations Author Contribution JC conceptualization, experiment planing and first draft of the document preparation. EB Experimental work and data analysis. MR Methodology design, data analysis and document correction 5. Acknowledgement Acknowledgment to the Ministry of science and technology of the Bolivarian Republic of Venezuela MinCyT for the support of the project: ”Sintesis y caracterizacion de grafeno y oxido de grafeno a partir de material biogenico modificado con nanoparticulas” References N.F. Tajul Arifin, N. Yusof, A.F. Ismail, J. Jaafar, F. Aziz, W.N. Wan Salleh, Graphene from waste and bioprecursors synthesis method and its application: A review, Mal. 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Licea-Jiménez, Selective band gap manipulation of graphene oxide by its reduction with mild reagents, Carbon 93 (2015) 967–973. https://doi.org/10.1016/j.carbon.2015.06.013. M. Acik, Y.J. Chabal, A Review on Reducing Graphene Oxide for Band Gap Engineering, JMSR 2 (2012) p101. https://doi.org/10.5539/jmsr.v2n1p101. A.A. Yadav, Y.M. Hunge, S.-W. Kang, Spongy ball-like copper oxide nanostructure modified by reduced graphene oxide for enhanced photocatalytic hydrogen production, Materials Research Bulletin 133 (2021) 111026. https://doi.org/10.1016/j.materresbull.2020.111026. R. Vijayan, S. Joseph, B. Mathew, Green synthesis of silver nanoparticles using Nervalia zeylanica leaf extract and evaluation of their antioxidant, catalytic, and antimicrobial potentials, Particulate Science and Technology 37 (2019) 809–819. https://doi.org/10.1080/02726351.2018.1450312. S.A. Bhat, N. Rashid, M.A. Rather, S.A. Bhat, P.P. Ingole, M.A. Bhat, Highly efficient catalytic reductive degradation of Rhodamine-B over Palladium-reduced graphene oxide nanocomposite, Chemical Physics Letters 754 (2020) 137724. https://doi.org/10.1016/j.cplett.2020.137724. M. Torabi Momen, F. Piri, R. Karimian, Photocatalytic degradation of rhodamine B and methylene blue by electrochemically prepared nano titanium dioxide/reduced graphene oxide/poly (methyl methacrylate) nanocomposite, Reac Kinet Mech Cat 129 (2020) 1145–1157. https://doi.org/10.1007/s11144-020-01722-x. S.M.A. Francis, V. Thiruvengadam, Catalytic Reduction of Rhodamine B and Crystal Violet using SnO2 – SiO2 Nanocomposite Derived from Rice Husk, 07 (2020). P.C. Nagajyoyhi, K.C. Devarayapalli, T.V.M. Sreekanth, S.V.P. Vattikuti, J. Shim, Effective catalytic degradation of rhodamine B using ZnCO 2 O 4 nanodice, Mater. Res. Express 6 (2019) 105069. https://doi.org/10.1088/2053-1591/ab3bbf. 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-4461351","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":310190493,"identity":"38d423e0-c5ac-45cd-9b9d-4d9048fe2e64","order_by":0,"name":"Elsy Bastidas","email":"","orcid":"","institution":"Universidad Central de Venezuela","correspondingAuthor":false,"prefix":"","firstName":"Elsy","middleName":"","lastName":"Bastidas","suffix":""},{"id":310190494,"identity":"07608268-221a-48c8-9807-82607a0857d6","order_by":1,"name":"Maria Rodriguez","email":"","orcid":"","institution":"Universidad Central de Venezuela","correspondingAuthor":false,"prefix":"","firstName":"Maria","middleName":"","lastName":"Rodriguez","suffix":""},{"id":310190495,"identity":"879ec10b-1dda-4fce-b96d-93daf4f306b8","order_by":2,"name":"Jimmy Castillo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYLCCBB4JIMl8AEhIyBCjgbEBooUtAaSFhzgtEJrHAEwSVM/ffvz5gwcyFtG6M3I+v7pRY8HDwH746AZ8WiTO5BiCHJa77UbuNuucY0CH8aSl3cCnxYAhhxGuxTiHDahFgscMvxb+5w+hWnKeGef8I0aLRALMYTnMj3PbiNAiceON4QywljPPzJhz+yR42Aj5hb8//cHHnz11uduOJz/+nPOtTo6f/fAxvFrAgLEHSAgksIEilIGNoHIw+AGy7wDzB+JUj4JRMApGwUgDAEx+SiDQy7p3AAAAAElFTkSuQmCC","orcid":"","institution":"Universidad Central de Venezuela","correspondingAuthor":true,"prefix":"","firstName":"Jimmy","middleName":"","lastName":"Castillo","suffix":""}],"badges":[],"createdAt":"2024-05-22 13:45:36","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4461351/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4461351/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57688193,"identity":"d3966df4-7894-4832-afe1-1d01e3c6964e","added_by":"auto","created_at":"2024-06-04 10:38:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1433646,"visible":true,"origin":"","legend":"\u003cp\u003eFigure in the left Partially oxidized graphene (GpO-Cu) layerswith copper and in the rigth GpO. The upper are SEM images, middle EDX analysis and bottom Element composition\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/99e7976c334f0f13e45606f5.png"},{"id":57688195,"identity":"ec91c326-3714-4767-8edc-f319347f4106","added_by":"auto","created_at":"2024-06-04 10:38:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1193944,"visible":true,"origin":"","legend":"\u003cp\u003eAFM image of GpO sheet(left) and GpO-Cu, the upper plot shows the line intensity profile showing the differences in the roughness of the sample due copper nanoparticles\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/6426b96cffd40249791ed55c.png"},{"id":57687830,"identity":"e8ea301b-1216-4649-beba-efb886e82376","added_by":"auto","created_at":"2024-06-04 10:30:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":511221,"visible":true,"origin":"","legend":"\u003cp\u003eContac angle of water onto surfeces (a) graphene oxide and (b) Copper nanoparticles adsorbed onto graphene oxide sheets\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/ee38256f8c8a2c75c77c5d2b.png"},{"id":57688643,"identity":"295f713b-3999-40db-a007-0a60746d19da","added_by":"auto","created_at":"2024-06-04 10:46:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":269855,"visible":true,"origin":"","legend":"\u003cp\u003eBET plot for GpO sample, the inset pore volume vs pore size plot\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/23ef6caea6df86f67060d64a.png"},{"id":57687827,"identity":"fda22b82-b8a5-440c-84fc-886c499c5749","added_by":"auto","created_at":"2024-06-04 10:30:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":319794,"visible":true,"origin":"","legend":"\u003cp\u003eAbsorbance as a function of Wavelength for samples Cu nanoparticles, GpO and GpO-Cu dispersed in water\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/16becccd4c61b8f0b81a7e6d.png"},{"id":57688196,"identity":"9b308575-be70-4f25-ab51-f0e97097a064","added_by":"auto","created_at":"2024-06-04 10:38:40","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":287925,"visible":true,"origin":"","legend":"\u003cp\u003eTau plot: (αh v)\u003csup\u003e2\u003c/sup\u003e vs Energy for GpO, GpO-Cu and Cu nanoparticles\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/2ce4ab07cd2d02d4df17b1d9.png"},{"id":57687834,"identity":"0f331b11-e2cc-4bf5-97be-f55919ab3360","added_by":"auto","created_at":"2024-06-04 10:30:40","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":293269,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra for GpO sample and GpO-Cu showing the changes after modification\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/229f07636109322cc05f650f.png"},{"id":57687837,"identity":"23507855-3473-4ffa-81bc-ff4b8f4b2167","added_by":"auto","created_at":"2024-06-04 10:30:40","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":322935,"visible":true,"origin":"","legend":"\u003cp\u003eDRX plot Intensity vs 2T for the GpO and GpO-Cu showing the peaks for graphene and for Cu and CuO\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/a2134ba617498d86814e1965.png"},{"id":57688197,"identity":"2f356f6f-a22f-4299-849e-0f16dbd81e99","added_by":"auto","created_at":"2024-06-04 10:38:40","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":233981,"visible":true,"origin":"","legend":"\u003cp\u003eEstructures of Rhodamine B and leuco form\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/48e0f3992dd67884e9c08cba.png"},{"id":57687838,"identity":"45a5ec2a-81d3-4363-b7b8-8add7e2b2a82","added_by":"auto","created_at":"2024-06-04 10:30:40","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":687046,"visible":true,"origin":"","legend":"\u003cp\u003eAbsorbance vs wavelength plots for RhB degradation experiment. (a) control sample with pure RhB and NaBH4, (b) RhB + NaBH4 + GpO sample, (c) RhB + NaBH4 + GpO-Cu sample\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/fde186c0c689d611882c3bce.png"},{"id":57687836,"identity":"9f61f609-5ff8-45f9-a743-6c6f719bb5f8","added_by":"auto","created_at":"2024-06-04 10:30:40","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":243066,"visible":true,"origin":"","legend":"\u003cp\u003eKinetic RhB degradation for GpO and GpO-Cu\u003c/p\u003e","description":"","filename":"floatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/e9483c88f5a41bc904d83784.png"},{"id":59613926,"identity":"b6e7e3bb-948f-4a5c-a2ce-400334bdc962","added_by":"auto","created_at":"2024-07-03 22:01:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7411790,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4461351/v1/fd7d1860-3681-4dd9-bea3-19ec83a948b1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Composite of graphene oxide from rice husks with copper nanoparticles immobilized: synthesis and application in catalytic dye degradation","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe use of biomass from different sources such as corn, coconut[\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], rice[\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], etc. has been reported as source of products of valuable interest, in special in energy generation. In particular, rice husks calcination have been used as a source of energy, and for the production of materials such as silica, activated carbon and graphene[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Rice husks have a 18% of silica and can be extracted through various physical or chemical processes to produce high-quality materials such as nanometric-sized silica, silicon, etc. Rice husks calcinated a 400 C, generate a carbonaceous material that can be transformed in graphene, and graphene oxide[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCharacterization of nanomaterials and particularly, graphene-derived materials, is essential to understand their potential applications. Techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectroscopy, and infrared absorption spectroscopy are used to precisely analyze these materials\u0026rsquo; structural properties, shape, size, and composition[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGraphene\u0026rsquo;s unique qualities, including its exceptional electrical conductivity, low thermal conductivity, and high affinity for hydrophobic compounds, make it a highly sought-after material. Products derived from graphene, such oxidized graphene[\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], have a very particular attraction since they allow maintaining intrinsic properties of the spatial arrangement of graphene sheets with special modifications that allow them to expand their application capacity. Utilizing advanced characterization techniques, including SEM, AFM, Uv-visible and infrared absorption spectroscopy, to gain a comprehensive understanding of the properties and structure of these versatile materials is essential for optimizing their synthesis and modification for integration into the latest technological innovations.\u003c/p\u003e \u003cp\u003eOne of the novelties of the process we are presenting is that it can obtain graphene oxide without the use of corrosive and highly polluting compounds like those employed by traditional methods, leading to simpler reactions.\u003c/p\u003e \u003cp\u003eGraphene has been used as an adsorbent in the treatment of water contaminated with dyes, pesticides[\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], etc., showing great effectiveness because of its large active surface area. The dye degradation process can be mediated by its oxidation or reduction in order to change from water insoluble to soluble. The products from reaction process are more easily for handle and disposal[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. If the dimensions of the graphene sheets are reduced, materials with greater adsorbency efficiency are obtained.\u003c/p\u003e \u003cp\u003eCopper in the zero-valent state functions as a catalyst in electrocalalitic and photo-catalytic reactions, since it allows modifications in conductivity band by interaction with the substrate and allows higher efficiency, reaction speed, and lower energy consumption in the reactions. Nanometric copper[\u003cspan additionalcitationids=\"CR23 CR24\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] has been tested as an electrocatalyst, showing higher efficiency than copper at macroscopic sizes. New materials, using a mixture of graphene and copper[\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] has been allowed the development of electrocatalytic materials usefully in the treatment of water contaminated with dyes and pesticides[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis work present the results of producing graphene oxide sheets (GOs) from rice husks with a easy an low reagent consuming methodology. The GOs is used as a support for copper oxide nanoparticles produced from the reduction of ionic copper adsorbed onto graphene sheets. The material is used as catalyst for the decomposition reaction of rhodamine B. The results of the characterization evidence the formation of copper nanoparticles on the surface of oxidized graphene with sizes of approximately 20 nm in size supported on micrometer sheets composed of 2 or 3 sheets. The GOs-CuO prove to be a good catalyst in rhodamine B degradation reaction.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Materials\u003c/h2\u003e \u003cp\u003eRice husk were provided by a local supplier. Potassium hydroxide (KOH) at 99% purity, Copper sulphate at 99% purity from sigma Aldrich and hydrochloric acid (HCl) 36%, Ascorbic Acid 99% purity and ethanol (\u003cem\u003eC\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e\u003cem\u003eH\u003c/em\u003e\u003csub\u003e5\u003c/sub\u003e\u003cem\u003eOH\u003c/em\u003e) HPLC grade from Merck were used.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Graphene Oxide and Graphene Oxide-Copper synthesis\u003c/h2\u003e \u003cp\u003eThe synthesis process for graphene from rice husks was performed with variations of the methodology reported by Muramatsu et all[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. In short, 100 gr of rice husks are washed with hydrochloridric acid 1 M and rinsed with distilled water. The clean rice husks are heated in air furnace at 400\u0026deg;C for 2 hours to calcine all the organic matter (cellulose, lignins, etc.). The solid residue obtained composed by carbon and silica is called rice husk ash. (RHA). The RHA is then mixed with solid KOH with a 2:1 proportion. The mixture is placed in a larger crucible and cover with a ceramic dish, them, the deposit is filled with rice husks twice the height of the small crucible to diminish contact with air and prevent oxidation of the mixture in the small pot. The system is heated at 800 \u0026deg; C for 2 hours. The result mixture was rinsed with distilled water until pH 7, to remove the residue of potassium salts.\u003c/p\u003e \u003cp\u003eThe solid was separated by centrifugation at 3200 revolutions per minute (RPM) for 30 minutes and then dried in an oven for 24 hours at 80 \u0026deg; C, partially oxidized graphene (GpO) is obtained. Graphene-Copper (GpO-Cu) is prepared by mixing the previous synthetize graphene with Copper sulphate followed by reduction with 1M ascorbic acid in pH 8 media. The material obtained is then evaluated using contact angle measurement, UV-vis and FTIR absorption spectroscopy, atomic force microscopy, dynamic light scattering, and scanning electron microscopy.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Catalytic reduction methodology\u003c/h2\u003e \u003cp\u003eRhodamine B (RhB) dye was used to evaluate the catalytic abilities of the prepared samples. For the catalytic reactions, 2.0 mL of 0.01 mM the RhB dye and 200 \u003cem\u003e\u0026micro;\u003c/em\u003eL of 0.4 M freshly prepared \u003cem\u003eNaBH\u003c/em\u003e\u003csub\u003e4\u003c/sub\u003e were mixed. The degradation efficiency was monitored using an ultraviolet (UV)-visible spectrometer (Neogen). Blank control experiments were performed without catalyst, Two 0.4 mg of different catalyzers were used, GpO and GpO-Cu.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Material Characterization\u003c/h2\u003e \u003cp\u003eGpO and the composite GpO-Cu morphology were confirmed by SEM using a Jeol JSM-6399 and AFM using a Bruker Dimension Edge. AFM measurements were performed in tapping mode with a silicon tip. The samples were supported in the sample holder by dispersing a minimum amount of material on a flat silicon surface. The chemical composition of all the materials were studied by FT Infrared spectroscopy using a Bruker FT-IR spectrometer. The UV-Vis spectra were measured with Ocean Optics spectrometer and the spectra were used to calculate variations in the Band-Gap. Composition and size were determined by XRD spectra were measured in Bruker D2 phaser.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003eThe SEM image analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), provides valuable information about the structure and composition of the graphene oxide sheets modified with copper nanoparticles. The image on (1 left) shows the graphene sheets after being modified with copper nanoparticles, with GpO sheets with sizes in the order of microns and small semi-transparent pieces on their surface, the EDX analysis and element composition.The presence of the bright spots in image (right) indicates the successful deposition of copper nanoparticles on the graphene oxide sheets, and the high density of these spots suggests a strong interaction between the copper nanoparticles and the graphene structure. This information is important for understanding the properties and potential applications of these GpO-Cu composites. Additionally, the EDX analysis confirms the presence of copper nanoparticles on the graphene oxide sheets. Overall, this SEM image analysis and EDX analysis provide valuable insights into the structure and composition of the GpO-Cu composites.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 AFM and Scanning Electron Microscopy\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shown the AFM image of GpO sheet (2A) and GpO with copper nanoparticles (2B), the line profile in the upper part of the images in the case of GpO shown a 2 nm thickness for the sample with few irregularities, showing a few layers composition (approximately 2 layers). In the case of the GpO-Cu the profile shown irregularities due the copper nanoparticles present in the GpO surface.\u003c/p\u003e \u003cp\u003eThe typical thickness of pure graphene sheets is approximately 0.35 nm as has been reported in previous works[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In the case of partially oxidized graphene the thickness of the sheets is increased due to the functional groups that are part of the structure[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and introduce spatial irregularities in the structure, so the intersheets distances could increase to a thickness of about 1 nm.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Contact Angle\u003c/h2\u003e \u003cp\u003eThe different forms of carbon can behave as hydrophilic or hydrophobic, depending on their structure and composition; in both graphite and carbon the hydrophilic character is associated with contaminants on the carbon surface[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] furthermore graphene is hydrophobic. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows images of a water droplet placed on a graphene surface (a) and a graphene surface with copper nanoparticles adsorbed to surface (b). It can be seen that in the case of GpO the contact angle is 124\u0026deg;, which confirms the degree of hydrophobicity of GpO. In the image on the right (b) shows a water drop almost completely spread on the surface of GpO-Cu with a contac angle of 7.5\u0026deg;, this variation in hydrophobicity due to the high content of copper nanoparticles, transforms a super hydrophobic surface in hydrophilic, due to the presence of copper nanoparticles. These materials composed of graphene and metals such as copper have applications in the processes of photoreduction and electrocatalysis, due to their conductive and catalytic properties, the ability to modify the hydrophobicity allows them to be applicable to the construction of membranes and with high efficiency in the interaction for both polar and low polarity molecules[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Specific surface Area\u003c/h2\u003e \u003cp\u003eThe specific surface area of graphene and its relative compounds determines many of its properties, such as adsorption capacity and conductivity.\u003c/p\u003e \u003cp\u003eIn the Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e the adsorption ratio vs relative pressure plot is presented, in the inset the pore volume as a function of pore width. The plot shown a surface area of 580 \u003cem\u003em\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e/g and a maximum pore size of 45.8 A. This specific surface area is in the range with reported in literature by Mohan et al[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], and correspond to partially oxidized graphene. BET curves of graphene with copper nanoparticles shown a similar behavior, copper nanoparticles does not decrease the adsorptive capacity of graphene significantly\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Uv-Visible spectroscopy\u003c/h2\u003e \u003cp\u003eThe shift in the UV-visible absorption spectra from graphite-derived to graphene oxide is a well-documented phenomenon. The peak shift from 262 nm in graphite-derived material to 230 nm in graphene oxide is indicative of the structural changes GpO. This strong absorbance band is attributed to the first \u003cem\u003eπ\u003c/em\u003e \u0026minus;\u0026minus;\u003cem\u003eπ\u003c/em\u003e\u0026lowast; transitions of aromatic C\u0026ndash;C bonds, with the degree of oxidation determining the aromaticity of the compound. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e displays the UV-visible spectra of three compounds: Cu nanoparticles, GpO, and GpO-Cu. The extinction spectrum of the copper nanoparticles shows two maxima at 367nm and 620nm, which are typical of the surface plasmon resonance of copper nanoparticles. The spectrum of the synthesized graphene sample has a maximum at 264 nm, indicating partially oxidized graphene; the more oxidized groups present, the more red shift of the band is observed. After reaction with copper, the graphene sheets show an absorbance spectrum with a maximum at 230 nm and another at about 698 nm. This spectrum suggests that copper has been initially coordinated to the oxidized groups of graphene and used as nucleation centers for the copper ions, which upon reduction of copper merge other copper ions to form copper nanoparticles in the surface.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFrom the UV-VIS absorbance spectrum a Tau plot is constructed. The Tauc optical bandgap is defined as the intercept Eg found from plotting:\u003c/p\u003e \u003cp\u003e(\u003cem\u003eαhν\u003c/em\u003e)\u003csup\u003e(1\u003cem\u003e/n\u003c/em\u003e)\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;\u003cem\u003eA\u003c/em\u003e(\u003cem\u003ehν\u003c/em\u003e\u0026thinsp;\u0026minus;\u0026thinsp;\u003cem\u003eEg\u003c/em\u003e)\u003c/p\u003e \u003cp\u003ewhere \u003cem\u003eα\u003c/em\u003e is the absorption coefficient, \u003cem\u003ehν\u003c/em\u003e is the photon energy in electronvolts (eV), A is a constant and Eg is the optical band-gap. The parameter n is related to the nature of the optical electronic transitions, being considered 1/2 or 2 for direct and indirect transitions, respectively. The optical band-gaps from the Uv visible spectra were determined using Tauc\u0026rsquo;s plot by assuming indirect transitions. These indirect transitions were considered due to the amorphous-like character of GpO and the GpO-Cu. The mechanism for describing variations in the graphene band gap has been reported previously[\u003cspan additionalcitationids=\"CR37\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Briefly, graphene oxide is composed of a mixture of sp\u003csup\u003e2\u003c/sup\u003e and sp\u003csup\u003e3\u003c/sup\u003e carbons, with the latter bonded to oxygen atoms forming hydroxyl, carbonyl and epoxy groups. Each of these groups has its own energy levels that contribute together with those of the sp\u003csup\u003e2\u003c/sup\u003e carbons in the formation of the overall structure of the system and its band gap. Including a metal additionally on its electronic structure and its band gap contributes to the whole, modifying the band gap of the system. Calculations were performed for GpO, Cu nanoparticles and the GpO-Cu. In Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, the Tau plot for all the samples is presented. GpO, exhibited a band gap of 3.98 eV[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], which is representative of a partially oxidized graphene with hydroxyl groups in its structure. In the case of Cu nanoparticles, the plot fit gives us a value of 3.41 eV for the band gap, which corresponds to copper nanoparticles with a low level of oxidation on their surface[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The reduction in band gap to 3.41 eV observed when graphene is modified with copper nanoparticles indicates improved photocatalytic characteristics. This decrease in band gap signifies a lower energy requirement for excitation and charge transfer processes, which can enhance the efficiency of photocatalytic reactions[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.5. FTIR spectroscopy\u003c/h2\u003e \u003cp\u003eThe intense and broad peak at a wavelength of 3420 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in the FTIR transmittance vs. wavelength plot confirms the presence of O-H bonds (hydroxyl groups) in the material. Additionally, the observed band at 1600 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponds to the C\u0026thinsp;=\u0026thinsp;C stretching present in the aromatic rings of the Gp-O. Furthermore, the C-O-C stretching bands at 1226 and 1015 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e confirm the presence of epoxy groups, indicating the successful synthesis of partially oxidized graphene. During the preparation of the graphene compound with copper, copper ions are brought into contact with the graphene, these ions interact with the charged groups and then copper reduction occurs, leading to a decrease in the oxidized groups of the graphene and their substitution by copper. This is shown in the spectrum of the GpO-Cu samples.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.6. X Ray difraction\u003c/h2\u003e \u003cp\u003eThe crystallinity and structural analysis of the as synthesized copper nanoparticles was investigates by powder X\u0026ndash;Ray diffraction technique. Figure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e represents the diffraction pattern of Cu nanoparticles in which the peaks at 2\u003cem\u003eθ\u003c/em\u003e value of 43.27 and 50.38 correspond to (111), (200) planes respectively[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e], confirms the cubic lattice of copper. All the diffraction peaks are in good agreement with the standard pattern for pure face centred cubic phase of copper nanoparticles (JCPDS No. 040836). The peack at 36.38 correspond to copper oxide[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], showing that the copper is partially oxidized on its surface. The calculated average size of the nanoparticles is calculated using the Scherrer equation; \u003cem\u003eD\u003c/em\u003e = (\u003cem\u003eKλ\u003c/em\u003e)\u003cem\u003e/\u003c/em\u003e(\u003cem\u003eβcos\u003c/em\u003e(\u003cem\u003eθ\u003c/em\u003e)). Were D is the crystalline size, K is being the shape factor, taken as 0.9, \u003cem\u003eλ\u003c/em\u003e is the wavelength of x-ray beam of 1.541 A, \u003cem\u003eβ\u003c/em\u003e is the full-width at half-maximum of the corresponding peak, and \u003cem\u003eθ\u003c/em\u003e is the Bragg\u0026rsquo;s diffraction angle. The peacks were fitted with seudo-voigd funtion showing an average diameter of 21.99 nm for the copper nanoparticles, this measurement results is consistent with Uv-visible data reported in literature and this paper. The band with a maximum at 2\u003cem\u003eθ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;21.59 corresponds to partially oxidized graphene. The presence of hydroxyl groups in oxidized graphene is responsible for the band shift at low 2\u003cem\u003eθ\u003c/em\u003e values. The layer spacing is calculated with \u003cem\u003eλ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;2\u003cem\u003edsin\u003c/em\u003e(\u003cem\u003eθ\u003c/em\u003e) with \u003cem\u003eθ\u003c/em\u003e the diffraction angle, from the spectra a interlayer of 0.8 nm is obtained, this value is higher than the observed for graphene pristine and this variation is due to oxidation degree in the graphene and consistent with the AFM profiles plots.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.7. Rhodamine B catalytic degradation\u003c/h2\u003e \u003cp\u003eThe rhodamine is a salt of Xantene that exhibits characteristic fluorescence due to the electron delocalization generated by the protonation of the nitrogen at position 3. In the presence of a reducing agent such as NaBH4, a hydrogen atom is transferred to C-6, resulting in the delocalization of electrons towards the tetra-nitrogen in position 3, which allows it to recover its aromaticity, with the subsequent loss of fluorescence (in the form of Leuco) as have reported previously[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. This reaction occurs at a very slow rate. The leuco form of rhodamine is more soluble, making its disposition simpler as it does not remain adsorbed in tissues and other materials. This allows for better disposal of the residues. In the Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e the rhodamine B reduction to Leuco form.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe degradation of Rhodamine B (RhB) in the presence of GpO and GpO-Cu was studied using solutions of rhodamine B in \u003cem\u003eNaBNH\u003c/em\u003e\u003csub\u003e4\u003c/sub\u003e as model. The mechanism of catalytic reduction of RhB with NaBH4 in presence of catalyst involves a series of steps[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]: Step I, the reducing agent (NaBH4) transfers a hydride to the catalyst surface, leading to the formation of M-H covalent linkages; Step II, adsorption of RhB dye molecules onto the surface of the catalyst, which is rate determining step; Step III, adsorbed RhB molecules undergo reduction by capturing electrons from the active sites of catalyst along with the adsorbed H; Step IV, the reduced form of RhB i.e. LRhB desorbs from the catalyst surface leading to reactivation of catalyst for its further catalytic activity. Since, step II, adsorption of RhB over catalytic surface is rate determining step in the reduction process of former, materials as graphene oxide with high adsorptive capacity is suitable for enhance the reaction. The band-gap determines the ease and availability of free energy states for the system to allow efficient load transfer. The decrease in the band-gap of graphene by including copper in its structure allows a faster and more efficient transfer, improving the reduction process. The solution composed of RhB with a excess of \u003cem\u003eNaBNH\u003c/em\u003e\u003csub\u003e4\u003c/sub\u003e is stable and show very low degradation at ambient conditions, In the experiment designed, high amounts of the reducing agent are used to ensure that it is in excess and that it is not a variable in the reaction, since the focus is on studying the effect of the catalyst. In a real exercise the amounts of the reducing agent would be limited to the minimum to avoid the formation of more contaminants. The residues produced can be removed by basic neutralization and adsorption techniques. Figure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e shows the absorbance spectrum of a sample (a) called control composed by RhB with a excess of \u003cem\u003eNaBNH\u003c/em\u003e\u003csub\u003e4\u003c/sub\u003e at different times, where it is observed that there is no change in the absorbance spectrum. For the same concentration solution with a 0.2 mg/mL of GpO, a degradation of RhB over time is observed, decreasing the absorbance significantly, the Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003eB. The GpO catalyzes the degradation reaction. For the RhB sample with GpO-Cu a higher degradation is observed at shorter times as is presented in the 10C. The surface of the partially oxidized graphene acts as a catalyst, it interacts with the molecule and shares free states which decreases the energy needed for the reduction process to take place, which decisively increases the rate of the reaction. Band gap results show that in the case of partially oxidized graphene decorated with copper the band gap is smaller, which explains the acceleration of the decomposition reaction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe catalytic degradation rates of the pollutants studied have been fitted by the Langmuir-Hinshelwood (L-H) kinetic model pseudo first order and the results showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, in it is observed that in the absence of catalyst the reaction cannot be carried out at ambient conditions, due to the energy required for the change is greater than available a this conditions as is showed in the Uv-vis spectra were the signal remain constant all times. When the RhB sample is placed in the presence of GpO, a rapid degradation is observed with a constant k\u003csub\u003eapp\u003c/sub\u003e = 0.1177, r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.89 and a reduction of 40% in a time of 10 min and maximum degradation of .68%. The catalyst composed of GpO-Cu increases the reaction constant by 8 times and decreases the reaction time to 1 min for total degradation. with a constant k\u003csub\u003eapp\u003c/sub\u003e = 0.821, r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.98 and a reduction of 98% in the first 8 min.\u003c/p\u003e \u003cp\u003eThe constant of the reaction are at least 5 time faster than published for catalizers like \u003cem\u003eZnCo\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e\u003cem\u003eO\u003c/em\u003e\u003csub\u003e4\u003c/sub\u003e or \u003cem\u003eSnO\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e/graphene or \u003cem\u003eTiO\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e/graphene[\u003cspan additionalcitationids=\"CR44\" citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Bhat et all[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] cite a complete list of results in reduction performance of different catalyst systems. expressed as k\u003csub\u003eapp\u003c/sub\u003e/gr and shown values from 0.005 to 181.5 for different catalyzers and 2553.2 for a Palladium Graphene oxide catalyst. In our work a k\u003csub\u003eapp\u003c/sub\u003e /gr of 34.0 was obtained, which is in the order of magnitude of the bests presented In the literature.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThe developed method based in utilization of carbonaceous residue from rice husks for the production of partially oxidized graphene presents an economically viable methodology for generating graphene sheets with specific functional groups. The synthesis produce a partially oxidized graphene (GpO) with unique properties. The spectroscopic data highlighting the presence of few-layered sheets with defects in their stacking pattern underscores the distinct nature of these graphene sheets, leading to notable changes in UV-visible spectra and AFM images. The subsequent modification of GpO through the addition of copper ions and their subsequent reduction results in the formation of graphene sheets with supported copper nanoparticles (GpO-Cu). The postulated process of copper ion interaction with polar groups in the oxidized graphene, serving as nucleation seeds in the reduction process and subsequent nanoparticle formation, is supported by UV-visible and FTIR spectra. The reduction in band gap observed when graphene is modified with copper nanoparticles signifies a lower energy requirement for excitation and charge transfer processes, which can enhance the efficiency of photocatalytic reactions. The catalytic potential of both GpO and GpO-Cu is evident in their ability to catalyze the decomposition reaction of RhB, with GpO-Cu exhibiting up to 8 times greater activity than GpO. This enhanced catalytic performance demonstrates the superior capabilities of these new catalysts compared to previously reported ones.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJC conceptualization, experiment planing and first draft of the document preparation. EB Experimental work and data analysis. MR Methodology design, data analysis and document correction\u003c/p\u003e\u003ch2\u003e5. Acknowledgement\u003c/h2\u003e \u003cp\u003eAcknowledgment to the Ministry of science and technology of the Bolivarian Republic of Venezuela MinCyT for the support of the project: \u0026rdquo;Sintesis y caracterizacion de grafeno y oxido de grafeno a partir de material biogenico modificado con nanoparticulas\u0026rdquo;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eN.F. Tajul Arifin, N. Yusof, A.F. Ismail, J. Jaafar, F. Aziz, W.N. Wan Salleh, Graphene from waste and bioprecursors synthesis method and its application: A review, Mal. J. Fund. Appl. Sci. 16 (2020) 342\u0026ndash;350. https://doi.org/10.11113/mjfas.v16n3.1491.\u003c/li\u003e\n\u003cli\u003eT.-H. Liou, Y.-K. Tseng, T.-Y. Zhang, Z.-S. Liu, J.-Y. 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Express 6 (2019) 105069. https://doi.org/10.1088/2053-1591/ab3bbf.\u003c/li\u003e\n\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":"[email protected]","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":"Graphene from biomass, Graphene catalytic reduction","lastPublishedDoi":"10.21203/rs.3.rs-4461351/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4461351/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eGraphene and its derivatives, such as graphene oxide, have a wide range of applications in industry, especially in electronics, electrode construction, catalyst in electro- and photocatalytic reactions, etc. This work presents results from the synthesis of graphene oxide sheets (GOs) from rice husks ash and its modification by incorporating copper nanoparticles. Rice husks, a low-value waste product generated in large quantities, were thermally treated to obtain a mixture of natural carbons with silica. This carbonaceous material was then reacted with potassium hydroxide to produce GOs. The GOs were modified using an impregnation and reduction process to immobilize copper metal nanoparticles onto their surface and obtain graphene oxide with CuO nanoparticles in their surface (GOs-CuO). The synthesized composites were characterized by FTIR, SEM, BET, XRD, and AFM, demonstrating that the formed structure is composed of graphene with predominantly copper oxide nanoparticles adsorbed on its surface. The band gap for the synthesized structures was determined by finding a significant decrease in the band gap of graphene oxide when copper nanoparticles are incorporated. Catalytic capacities of synthetized samples were tested in the decomposition reaction of pollutants, using Rhodamine B (RhB) as a model molecule due to its environmental persistence and toxicity. Both GOs and GOs-CuO effectively degraded RhB, with GOs-CuO demonstrating a 8-fold faster kinetic rate, highlighting its potential for pollutant remediation applications.\u003c/p\u003e","manuscriptTitle":"Composite of graphene oxide from rice husks with copper nanoparticles immobilized: synthesis and application in catalytic dye degradation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-04 10:30:35","doi":"10.21203/rs.3.rs-4461351/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","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":"3c4e7ced-fba2-4bbb-9ba4-77a8ed3706ab","owner":[],"postedDate":"June 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-03T21:53:27+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-04 10:30:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4461351","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4461351","identity":"rs-4461351","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}