Sulfur doped Zinc Oxide-Nikel Oxide as Efficient Bifunctional Electrocatalyst for overall Water splitting

Sulfur doped Zinc Oxide-Nikel Oxide as Efficient Bifunctional Electrocatalyst for overall Water splitting | 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 Sulfur doped Zinc Oxide-Nikel Oxide as Efficient Bifunctional Electrocatalyst for overall Water splitting Faiq Saeed, Samia arain, Wang Yong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4441679/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Oct, 2024 Read the published version in Electrocatalysis → Version 1 posted 8 You are reading this latest preprint version Abstract A mixed Sulfur-doped zinc oxide-nickel oxide nanocomposite electrocatalyst for oxygen evolution reaction (OER) was prepared. By hydrothermal method, we prepared a high-efficiency OER electrocatalyst doped with zinc oxide and nickel oxide. By applying different characterizations, the material was proven to be a new phase of (S-doped-ZnO-NiO). S-doped ZnO-NiO, ZnO-NiO did not show excellent performance. At 10 mA cm − 2 , the generation potential of OER is 1.45 V and that of HER is -0.04 V. This unique morphology results in better OER performance of 240 mV at 10 mA cm − 2 in the KOH electrolyte, and similarly, the S-doped ZnO-NiO shows us excellent long-term stability in alkaline media with a small Tafel slope (77 mV dec − 1 ). S-doped ZnO-NiO hybrid catalysts offer great potential for electrochemical devices due to their low cost and high activity. we have successfully constructed an electrocatalyst with the dual functions of HER and OER, which can achieve efficient water splitting. Sulfur Doped ZnO-NiO OER HER Water Splitting Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Highlights S-doped ZnO-NiO showed excellent activity catalyst. S exhibit excellent HER performance under alkaline condition. The Structural feature of ZnO is profit when added Sulfur increases the surface activity. 1.Introduction Renewable energy resources are the most sought-after area of study that is vital to the world's future and present [ 1 ] . The sun, wind, geothermal energy, carbon dioxide, and other non-depleting sources are among the energy-producing options that can provide energy continually [ 2 ] . Using renewable resources to create power is a very practical method that involves splitting water into pure hydrogen and oxygen [ 3 ] . Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are two examples of reactions that combine to form water splitting. For both procedures to work as electrodes in practical applications, an electrocatalyst is required [ 4 – 5 ] . For the HER reaction, the electrocatalyst should follow a simple mechanism of low over potential [ 6 ] . OER activity, which requires a much greater potential than the HER reaction to transfer four electrons, is the main hindrance in the water splitting reaction. By utilizing many stages with a higher activation energy, this can be avoided [ 7 – 8 ] . To solve this problem with electrocatalyst for OER, researchers proposed ruthenium and iridium oxide as a benchmark OER catalyst. The main drawback of binary benchmark catalysts is their expensive cost and limited availability when it comes to large-scale production [ 9 – 10 ] . Because transition metal oxides are present, there is a great interest among young researchers to investigate the creation of proportionate OER performance catalysts with excellent durability, cheap cost, and efficiency [ 11 – 12 ] . In addition to other transition metal oxides, several efforts are being made to develop nickel-based oxides and their composites as a suitable electrocatalyst to replace RuO 2 and IrO 2 OER catalysts. It has been strongly suggested that these binary oxides make excellent electrocatalysts [ 13 ] . As a result, S, ZnO, and NiO are excellent, stable, abundant, and possess noteworthy electrochemical qualities when used as electromagnetic catalysts [ 14 ] . It is used in a variety of potential applications, such as super capacitors, batteries, sensors, and electrochromic devices. Because the shape of the electrocatalysts had a major impact on their electrochemical capabilities, scientists were able to generate a wide range of nanostructures, including porosity, nanoflower, nanorod, nanotube, and nanowire forms. It significantly affects the ability of the electrocatalysts to transfer charges [ 15 ] . Researchers have used a variety of synthetic methods to create these novel nanostructures. Among these, hydrothermal, sol-gel, co-precipitation, and other techniques are the most useful. The present work synthesizes S doped ZnO-NiO nanoclusters via a simple hydrothermal process. It is inexpensive, good for the environment, and easily adjusted [ 16 ] . Because of the possible uses for nickel oxide nanostructures, several researchers have recently developed an interest in them. Testing for genotoxicity on nickel oxide nanoparticles has been demonstrated by Naresh Dumala and colleagues [ 17 ] . Wang et al. reported on nickel oxide nanoparticles for solar cell applications [ 18 ] . Ensafi and colleagues worked on nickel nanoparticles supported on porous silicon flour for a nonenzymatic electrochemical glucose sensor [ 19 ] . Sun and associates were investigating the application of nickel oxide nanoparticles in electrochromic materials [ 20 ] . Abdalla and associates employed multiwalled carbon nanotubes as sacrificial templates to produce nickel oxide nanotubes for usage in supercapacitor applications [ 21 ] . S doped ZnO-NiO was investigated by Abdur Rahman and colleagues using co-precipitation procedures [ 22 ] . Liu et al. revealed the usage of S doped ZnO-NiO in water splitting [ 23 ] . Choudhary and colleagues synthesized NiO nanodisks for biological applications [ 24 ] . Khan examined the characteristics of NiO nanofibers with his lab colleagues [ 25 ] . Along with his collaborators, Aguilar created nanofluids based on NiO for use in solar applications [ 26 ] . Soundararajan et al. described NiO nanoparticles relevant to lithium-ion batteries [ 27 ] . Ni nanoparticles were created by Hu and his group for industrial use [ 28 ] . The virgin, 20% Suphur Zn 10%, and Ni 10% nanocluster form is effectively manufactured for electrochemical OER applications using a straightforward hydrothermal technique. Improvement of the NiO nanostructure and the Zn 2+ ion function in the NiO host matrix have been discussed in detail. The physical and electrochemical characteristics of virgin NiO are correlated with the dopant effect. Based on estimation, the ideal dopant concentration of Zn 2+ with NiO host provided the greater electrochemical response, which has been extensively studied. We outlined the performance of a catalyst based on S, ZnO, and NiO for the OER reaction in basic medium since we are very inspired by these capabilities of transition metals. The new hybrid catalyst for the oxygen evolution process (OER) has been found to be more stable and active. The S doped ZnO-NiO for the activity of OER at low temperature towards effective overall water splitting was described in this study. When S-doped is doped with ZnO-NiO as a Sulfur source thiourea is the newly manufactured catalyst. Because Sulfur is added to transition metals, this Sulfur-doped catalyst (S doped ZnO-NiO) is very active toward OER. When compared to noble metal-based catalysts like IrO 2 , RuO 2 , and Pt/C, our newly synthesized catalyst exhibits higher OER activity. This catalyst's synthesis process is depicted in Fig. 1 a. 2. Experimental detail Thiourea, as sulfur source, zinc nitrate hexahydrate (Zn (NO 3 ) 2 ·6H 2 O) (≥ 99% purity, Sigma Aldrich), nickel nitrate hexahydrate (Ni (NO 3 ) 2 ·6H 2 O) (≥ 98% purity, Merck), urea (CH 4 N 2 O) (≥ 99% purity, Sigma Aldrich), and hexamethylenetetramine were among the analytical grade products obtained and utilized. The entire experiment was conducted with deionized water. Preparation of S doped ZnO-NiO nanocomposite The S doped ZnO-NiO composite was fabricated by hydrothermal method. 0.5 g thiourea was dissolved in 100 mL deionized water 0.1 M solutions each of nickel nitrate and zinc nitrate were prepared and mixed with thiourea solution under stirring. A 0.05 M solution of hexamethylenetetramine (HMTA) was prepared and mixed with metal nitrate solution in thiourea under stirring for 2 h. The mixture was heated in a 150 mL Teflon autoclave for 24 h at 180 °C. The formed precipitates were washed several times with ethanol and water, dried at 90 °C. The dried grained powder was then calcined at 400 °C for 2 h in a tube furnace [ 29 ] . After calcination, the final product was collected and used for further characterization. Undoped ZnO-NiO nanocomposite was also prepared using the same experimental conditions and precursor materials without thiourea. Characterizations After fabrication, the samples were characterized using different techniques. XRD was performed on a D/MAX-2500 X-ray diffractometer equipped with Cu Kα radiation at 40 kV and 40 mA at a scanning rate of 10 °C min -1 . SEM images were obtained with Hitachi S-4800 FE-SEM. XPS was performed with a PHI-1600 equipped with Al Kα radiation. The binding energy was calibrated by the C1s peak (284.8 eV) of the contamination carbon. Surface area was examined using the BET instruments 3H-2000 PS2. Electrochemical measurement Nickel foam was soaked in diluted HCl and allowed to dry at 60 °C overnight. 5–10 mg of the fabricated sample was mixed with 20–30 µL of Nafion binder, and 1 milliliter of 99% analytical grade ethanol. The mixture was sonicated for 10 min to form a homogenous paste. The homogenous paste was transferred loaded onto the surface of Ni-Foam using a micropipette. The foam was dried at ambient temperature and then annealed at 300 °C for 2 h. The activity of the electrocatalyst was measured using electrochemical workstation with the help of IVIUMSTAT workstation (IVIUM Technologies BV, Netherlands). The workstation was typically composed of three electrodes: a working electrode (catalyst on Ni-foam), a graphite rod as a counter electrode, and Ag/AgCl as a reference electrode. Each experiment was conducted in 1 M KOH solution at a scan rate of 5 mV s -1 . Furthermore, the active surface area of the electrocatalyst was derived from ( C dl ) within 10–90 mV s -1 range. With a reversible hydrogen electrode, all the electrode potentials and LSV were adjusted. The following equation was used as a reference, E RHE =E(Ag/AgCl) + 0.059 pH + 0.196 (5.1) Each time, a pH meter was used to measure pH of the solution keeping 5 mV s -1 as the LSV scan rate. 2.1 Result and Discussion Sulfur doped ZnO-NiO nanocomposite were produced using a simple hydrothermal technique. The XRD patterns of the electrocatalyst are shown in Fig. 5- 1 b along with the standard cards sulfur (JCPD:04-007-2083), ZnO (JCPDS card No. 01-078-3315) and NiO (JCPDS card No. 01-071-1179). The crystal structure was investigated by exposing the prepared S doped NiO-ZnO samples. was observed as a set of sharp peaks at 2θ S which is represented by 101, 300, 12 − 1, 21 − 2, 15 − 1, matched with sulfur (JCPD:04-007-2083), for ZnO at 2θ 31, 34, 36, 47, 56, 67, 68, and 69 representing 100, 002, 102, 110, 200, 112, and 201 hkl planes of ZnO was observed. All these peaks are characteristic peaks of the hexagonal Wurtzite structure of ZnO. These peaks have been compared with standard diffraction data of ZnO (JCPDS card No. 01-078-3315). Another set of diffraction peaks at 2 thetas 37, 43, and 63 representing the 111, 200, and 220 hkl planes of NiO was noted in XRD patterns. These peaks are characteristic peaks of the Face-centered cubic structure of NiO (JCPDS card No. 01-071-1179) can see the XRD pattern in Fig. 1 b. Figure − 1c demonstrates the SEM images of the fabricated electrocatalyst at different magnifications. Apparently, the sample presents a flower-like uniform morphology. The nanoparticles are uniformly distributed with very little tendency of agglomeration. At lower magnification, the formation of uniformly distributed S doped ZnO-NiO nanoflowers is clearly visible. Close inspection of the material under a little higher magnification reveals few structures that resemble bulk in addition to the flower. The EDX spectra of the sample in Figure − 2 demonstrates the signals of O, Zn, Ni, and S to verify the synthesis of S doped ZnO-NiO. The molar content of the elements S, Zn, O and Ni is approximately 43.88, 31.68, 9.59 and 1.559% respectively as shown in Table .1. Table .1: Elemental Percentage of S, Zn, Ni, O and C Element Weight % Net Weight Atomic weight S 43.88 0.54 42.50 Zn 31.38 0.47 15.05 Ni 9.53 0.43 5.07 O 13.29 0.76 34.37 C 1.55 0.17 3.01 100.00 100.00 The uniform distribution of the elements in the fabricated nanocomposite is further confirmed from the elemental mapping of the constituent elements as shown in Figure − 1e. The existence of different components, chemical nature, and bonding in S doped ZnO-NiO were investigated using XPS as displayed in Figure − 3 The survey spectrum in Figure − 3a characterizes the presence of all the constituent elements such as S, Zn, Ni, and O. The introduction of sulfur is confirmed by two peaks of S 2p 1/2 and 2p 3/2 at 162.01 and 163.21 eV respectively in S figure − 3b, while sulfur oxide is revealed by a peak at 169.52 eV [ 30 ] . With a spin-orbit splitting of 23.07 eV, peaks at 1022.35 eV and 1045.43 eV correspond to Zn 2p 3/2 and Zn 2p 1/2 respectively as shown in Figure − 3c confirming a Zn 2+ oxidation state for Zn in the composite [ 31 ] . The high-resolution Ni XPS spectrum reveals five Ni-related peaks. The peaks at 855.95 eV and 873.51 eV respectively correspond to Ni 2p 3/2 and Ni 2p 1/2 , validating a Ni 2+ oxidation state as shown in Figure − 3d. The availability of the O 1s peak at 530.69 eV demonstrates the existence of lattice oxygen in the nanocomposite as shown in Figure − 3e [ 32 – 33 ] . The XPS survey spectrum and high-resolution XPS spectra confirmed the existence of all the elements presented in the S doped ZnO-NiO composite. From all this discussion, unique elemental compositions, chemical structures, and bonding characteristics of S@Zno-NiO can be assured. The spectrum data has revealed the existence of diverse oxidation states and bonding interactions among Sulfur, Zinc, Nickel, and Oxygen to confirm the complex nature of the catalyst's composition. Furthermore, the exposed surface area of S@Zno-NiO was investigated by BET, and the definite surface area for all samples is shown in Table 2. The surface area of the Sulfur doped Zinc Oxide and Nickel Oxide is found to be 69 m 2 g − 1 , which is greater than the individual surface area of ZnO-NiO (66 m 2 g − 1 ) in Table-2. This larger surface area of S@Zno-NiO is more beneficial for better electron transfer and can lead to better catalytic performance. Moreover, it is worth noting that S@Zno-NiO has a large surface area and can show better performance for HER and OER 2.3 Electrocatalytic OER performance In a 1 M KOH solution, we investigated the S doped binary oxides for OER. The OER polarization curves were recorded at a reduced scan rate (5 mV s − 1 ). The LSV of S doped ZnO-NiO, ZnO, NiO, and IrO 2 in alkaline environment at a current density of 10 mA cm − 2 are displayed in Figure − 4a.and the corresponding histograms Figure − 4b Compared to IrO 2 , the activity of S doped ZnO-NiO binary oxides is superior. A potential of 230 mV at 10 mA cm − 2 is demonstrated by the synthesized catalyst, which performed better than the RHE value for IrO 2 (310 mV at 10 mA cm − 2 ) [ 34 ] . This newly synthesized catalyst, containing S, ZnO, and NiO, provides more evidence that electrocatalysis is improving. In addition, a Tafel plot illustrating the connection between current density and overpotential is generated to explore the catalytic kinetics for OER. Figure − 4c displays a comparison of the Tafel slope values for each sample. Tafel slope values for S doped ZnO-NiO are determined to be 77 mV dec − 1 and 63 mV dec − 1 , while IrO 2 shows only 115 mV dec − 1 . The increased conductivity of the Tafel slope supports improved OER. Less than 120 mV dec − 1 is a more favorable Tafel slope value for OER [ 35 ] . The turnover frequency (TOF) is another essential factor in evaluating the better performance of OER [ 36 – 37 ] . At a potential of 230 mV, S doped ZnO-NiO has a TOF of 0.15 (s − 1 ), which is higher than IrO 2 . The superior performance of OER is demonstrated by the greater TOF value of S doped ZnO-NiO as shown in Figure − 4e. Another important parameter to analyze the kinetics of the catalytic process is the electrochemical impedance spectroscopy (EIS) which shows the charge transfer resistance in the nanocomposite. The fast electron transmission method is frequently associated with the smaller semicircle of EIS. A sizable semicircle and a greater charge transfer resistance of roughly 140 Ω are displayed by the ZnO-NiO. On the other hand, the resistance approaches 90 Ω when S is added. By simultaneously adding sulfur, the electron transfer throughout the catalytic process is frequently facilitated. It is notable that S doped ZnO-NiO of 90 Ω has a lower charge transfer resistance (Rct) than ZnO-NiO as demonstrated in Figure − 5c. Furthermore, an electrocatalyst's improved performance depends on its electrical conductivity and quantity of active sites [ 38 – 39 ] . Progressive activities are a result of the catalysts' improved active sites and increased conductivity. By serving as a conductive background for quicker electron transfer, the ZnO improves the catalytic properties of water splitting. As an additional parameter, the CV are shown in Figure − 5a at different scan rates (10–80 mV s -1 ). Every CV curve boosts the C dl by representing a whole rectangular performance at every scan rate. The C dl normalizes the exchange's current density and is directly correlated with the catalyst's active site count, indicating increased catalytic activity [ 40 ] . As can be shown in Figures − 5b, the C dl value of our sample is 63 mA cm -2 , which is noticeably higher than the values reported by any other synthetic sample. NiO had a higher current density, however adding ZnO produced more active sites. Additionally, the remarkable efficacy of S-doped ZnO-NiO is demonstrated by its stability, which is a crucial factor that confirmed the catalytic activity of the produced catalyst. The catalyst S doped ZnO-NiO provided better stability for 6 h in alkaline electrolyte and no significant changes are noted during this period. 2.4 Electrocatalytic HER performance To evaluate the HER activity of samples, the HER polarization curves of S-doped ZnO-NiO, Zno-NiO and Pt/C were compared with those of a state-of-the-art and deposited with the binder. The HER profiles of S-doped ZnO-NiO, Zno-NiO and Pt/C are exhibited in Fig. 6 a and the corresponding histogram Fig. 6 b the electrochemical performance of the prepared material was demonstrated by measuring the overpotential. The observed Over Potential for S@Zno-NiO, ZnO-NiO, Pt/C 170 mV, 140 mV, and 180 mV respectively Our best sample, S@Zno-NiO, has a modest potential of 30 mV at 10 mA cm -2 for HER with a greater current density. The outcomes of HER initiatives correlate with commercial catalysts like Pt/C. The results showed that the performance of ZnO-NiO was lower (170 mV) at 10 mA cm -2 , both on Ni-foam and on the material itself. Additionally, transition metal alloy is essential for improving the HER [ 41 ] . Tafel slopes were also calculated by using LSV data and shown in Fig. 6 c which represents the stage in the electrocatalytic hydrogen generation process that establishes the rate and the likely mechanism for S@Zno-NiO, Zno-NiO, and Pt/C which were 97 mV dec − 1 , 92 mV dec − 1 , and 30 mV dec − 1 , respectively exhibit that it has excellent reaction kinetics and electron transfer efficiency for HER. Our novel bifunctional catalyst showed significant results. The turnover frequency (TOF) measurement for S-doped ZNo-NiO is also 1.01 s − 1 at 30 mV overpotential at 10 mA cm − 2 . This is significantly better than the (TOF) values shown in Figure − 6e for S doped ZnO-NiO, S ZnO-NiO and Pt/C. A further essential component of the catalyst's catalytic activity is its exceptional stability. Our best catalyst (S doped ZnO-NiO,) demonstrated HER stability throughout 5 h. The current range shown in Figure-6d is constant because there is no variation during this time. The entire mechanism underlying S doped ZnO-NiO ' improved performance for both HER and OER is still unknown. Furthermore, it is anticipated that the catalyst's performance has been improved by the ZnO, the addition of sulfur as an active metal, and the distinctive shape of the transition metal alloy. Additionally, ZnO and sulfur need to be able to connect with another substance [ 42 – 43 ] . Table .2 Electrochemical activities for all samples. Table.2 Electrochemical activities for S doped ZnO-NiO and ZnO-NiO. Name of catalyst Surface area OER at 10 mA cm − 2 OER at 50 mA cm − 2 HER at 10 mA cm − 2 HER at 50 mA cm − 2 Tafel slope for OER Tafel slope for HER Water Splitting at 10 mA cm − 2 S-doped ZnO-NiO 69 m 2 g − 1 230 mV 245 mV 30 mV 18.6 mV 77 mV dec − 1 97 mV dec − 1 1.49V ZnO-NiO 66 m 2 g- 1 310 mV 280 mV 160 mV 34.5 mV 63 mV dec − 1 92 mV dec − 1 ------- Pt/C 30 mV dec − 1 It is anticipated that sulfur's valence shell electrons are incomplete; sulfur must connect with another molecule to finish the valence shell. An essential step for OER and HER is the absorption of the water molecules on the catalyst surface, which is facilitated by the presence of partially positive and partially negative ions. Additionally, the catalyst for water splitting was improved by a more excellent synergistic link between sulfur and Zno as well as NiO with a distinctive cylindrical structure. On the other hand, excellent performance for HER and OER is also anticipated from the catalyst due to its active surface area and readily available redox sites. Therefore, based on the earth-abundant metal electrocatalyst, S doped ZnO-NiO is a novel bifunctional electrocatalyst for energy conversion. 3. Electrocatalytic Water Splitting The S doped ZnO-NiO was further investigated as the same electrocatalyst on both anode and cathode electrodes with a two-electrode system to evaluate its performance for overall water-splitting reaction in 1 M KOH solution. As shown in figure − 7a and the corresponding histogram figure − 7b the LSV curve of S doped ZnO-NiO, the onset voltage for water-splitting is 1.49 V and 10 mA cm − 2 current density Remarkably, only a slight increase in the overpotential is seen after studying the durability of S doped ZnO-NiO for 10 h at 10 mA cm -2 we can see in figure − 7c. Because it has a higher current density, S doped ZnO-NiO are initially employed for overall water splitting. This might be because of the unfamiliar double electrode environment; however, after 30 min, it showed a consistent potential of 1.49 V at 10 mA cm -2 . Furthermore, we have compared our catalyst with other published catalyst the details are shown in Table .3 Table: .3 Summarized bifunctional electrocatalysts presented in alkaline media. Overpotentials and cell voltages other than at η 10 and 10 mA cm − 2 respectively are mentioned. Electrocatalyst Support / Substrate Electrolyte HER η 10 (mV) OER η 10 (mV) Cell Voltage (V) at 10 mA cm − 2 Ref S doped ZnO-NiO Ni-Foam 1 M KOH 77 230 1.49 This work Ni-Fe 2 B/NF Ni foam 1 M KOH 115 250 48 Cr-FeNi-P Ni-Foam 1 M KOH 190 240 1.50 49 Ni 0.82 Co 0.18 O @C Ni foam 1 M KOH 62 98 320 50 MoOx /Ni 3 S 2 Ni-Foam 1 M KOH 106 136 1.45 51 FeP/Ni 2 P Ni-Foam 1 M KOH 140 154 1.42 52 CoMoNiS-NF-xy Ni-Foam 1 M KOH 105 255 1.45 53 NiFe Ni-Foam 1 M KOH 100 78 236 54 (Ni 0.33 Fe 0.67 ) 2 P Ni-Foam 1 M KOH 214 230 1.41 55 Fe-CoP Ni-Foam 1 M KOH 78 227 1.49 56 N-Ni 3 S 2 Ni-Foam 1 M KOH 110 350 1.48 57 The outstanding catalytic activity and better stability of (S@Zno-NiO) on Ni-Foam are based on the following illustrious factors, sulfur and binary compound are highly reactive, and similarly, metallic oxide and binary oxide are extremely responsive towards OER [ 44 ] .Transition metal alloy is also reactive towards HER activities, here in our catalyst ZnO and NiO is presented in a unique morphological form, which is evidence for better activity for HER [ 45 – 47 ] . The porous morphology of the Ni-foam electrode not only confirms easy contact of the surface-active sites with the electrolyte but also improved the OER and HER activities. 4. Conclusion We have effectively synthesized a hybrid electrocatalyst (S-doped-ZnO-NiO) for the Oxygen Evolution Reaction using a straightforward experimental approach that is also practical for common industrial use. Our hybrid catalyst exhibits long-term durability in alkaline electrolytes and has the potential to replace noble metal catalyst for the Oxygen Evolution Reaction (OER) at an overpotential of 230 mV at 10 mA cm − 2 . Furthermore, this work offers a safe and simple method to use this electrocatalyst for industrial application in addition to a stable and effective low-cost electrocatalyst for OER. Declarations Author contributions Wang Yong conceived the project, designed the experiments, intercepted the data, and finalized the manuscript. The first draft of the manuscript was written by Faiq Saeed, and. Samia Faiq Saeed performed all the electrochemical measurements and recorded the X.R.D. data Samia Provided SEM/EDS images and analysis. Faiq Saeed provided the XPS data and analysis. All authors revised and commented on the manuscript. Funding Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgement We acknowledge the support from National Natural Science Foundation of China (22274109, 21976131). References D. Aboelela, H. Saleh, A.M. Attia, Y. Elhenawy, T. Majozi, M. Bassyouni, Recent Advances in Biomass Pyrolysis Processes for Bioenergy Production: Optimization of Operating Conditions [J]. 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Jin, Earth-Abundant Metal Pyrites (FeS 2 , CoS 2 , NiS 2 , and Their Alloys) for Highly Efficient Hydrogen Evolution and Polysulfide Reduction Electrocatalysis [J]. J. Phys. Chem. C 118 (37), 21347–21356 (2014) R. Li, Z. Wei, X. Gou, Nitrogen and Phosphorus Dual-Doped Graphene/Carbon Nanosheets as Bifunctional Electrocatalysts for Oxygen Reduction and Evolution [J] , vol. 5 (ACS Catalysis, ACS,, 2015), pp. 4133–4142. 7 G. Wu, K.L. More, C.M. Johnston, P. Zelenay, High-performance electrocatalysts for oxygen reduction derived from polyaniline, iron, and cobalt [J] , vol. 332 (Science, American Assoc for the Advancement of Science,, 2011), pp. 443–447. 6028 M.S. Burke, L.J. Enman, A.S. Batchellor et al., Oxygen Evolution Reaction Electrocatalysis on Transition Metal Oxides and (Oxy) hydroxides: Activity Trends and Design Principles [J]. Chem. Mater. ACS. 27 (22), 7549–7558 (2015) N. Mahmood, C. Zhang, Y. Hou et al., Nickel Sulfide/Nitrogen-Doped Graphene Composites: Phase-Controlled Synthesis and High-Performance Anode Materials for Lithium-Ion Batteries [J]. Small. 9 (8), 1321–1328 (2013) M.S. Ahmed, B. Choi, Y.B. Kim, Development of Highly Active Bifunctional Electrocatalyst Using Co 3 O 4 on Carbon Nanotubes for Oxygen Reduction and Oxygen Evolution [J]. Sci. Rep. 8 , 2543–2551 (2018) K. Xu, P. Chen, X. Li et al., Metallic Nickel Nitride Nanosheets Realizing Enhanced Electrochemical Water Oxidation [J]. J. Am. Chem. Soc. 137 (12), 4119–4125 (2015) Q. Zhou, Z. Shen, C. Zhu et al., Nitrogen-Doped CoP Electrocatalysts for Coupled Hydrogen Evolution and Sulfur Generation with Low Energy Consumption [J]. Adv. Mater. 30 (27), 1800140 (2018) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Oct, 2024 Read the published version in Electrocatalysis → Version 1 posted Editorial decision: Revision requested 07 Jul, 2024 Reviews received at journal 11 Jun, 2024 Reviewers agreed at journal 30 May, 2024 Reviewers agreed at journal 30 May, 2024 Reviewers invited by journal 30 May, 2024 Editor assigned by journal 22 May, 2024 Submission checks completed at journal 21 May, 2024 First submitted to journal 18 May, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-4441679","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":308726713,"identity":"8ece354c-59dd-4a99-a248-c09cd390d50e","order_by":0,"name":"Faiq Saeed","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYDCCA4wPGBIgTMMHQC4xWpgNYFqMDYjXAgVmEkRp4bt9mPHDg7I6eX725m3VPDV35PgZmB8+uoFHi+S5ZGaJhHOHDWf2HCu7zXPsmbFkA5uxcQ4eLQZn+A9IJLYdYNxwI8fsNg/b4cQNB3jYpPFrYWb+kdhWZ7///huzYp5/xGlhA9rCnLhBgseMmbeNCC2SQC0WQL8kzziTViw5t++wsWQzAb/wAR1280dZnW1/++GNH958OywHDLqHj/FpgQA2CMXEAyKZCSpH0sL4gyjVo2AUjIJRMNIAAFqNUGGDneMMAAAAAElFTkSuQmCC","orcid":"","institution":"Tianjin University","correspondingAuthor":true,"prefix":"","firstName":"Faiq","middleName":"","lastName":"Saeed","suffix":""},{"id":308726714,"identity":"1455df6b-bc04-49af-bfbb-9564dd8309ce","order_by":1,"name":"Samia arain","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Samia","middleName":"","lastName":"arain","suffix":""},{"id":308726715,"identity":"b8f2b503-eda0-4cae-a945-6890e4b7be8e","order_by":2,"name":"Wang Yong","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Wang","middleName":"","lastName":"Yong","suffix":""}],"badges":[],"createdAt":"2024-05-18 15:53:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4441679/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4441679/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12678-024-00896-5","type":"published","date":"2024-10-01T15:57:39+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":57497393,"identity":"fb314c61-7265-4d2f-9af3-043a652e9a87","added_by":"auto","created_at":"2024-05-31 13:05:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1043959,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic structure of S doped ZnO-NiO;(b) XRD Pattern of S doped ZnO-NiO, ZnO, NiO;(c) SEM Image of S doped ZnO-NiO at 250 nm;(d) SEM Image of S doped ZnO-NiO at 0.5 µm (e) Elemental mapping of S doped ZnO-NiO at 5 µm.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/38d6ef8aaa3785f4fe43a854.png"},{"id":57496661,"identity":"34931858-bf93-4f9d-8248-52c2a966f3f1","added_by":"auto","created_at":"2024-05-31 12:49:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":33444,"visible":true,"origin":"","legend":"\u003cp\u003eEDX of S, Zn, Ni, O and C.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/bc941a669378886693d4cf13.png"},{"id":57497080,"identity":"af741da9-bbe8-451c-a982-f69b67213a99","added_by":"auto","created_at":"2024-05-31 12:57:40","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":100311,"visible":true,"origin":"","legend":"\u003cp\u003eOverall Spectra of Catalyst of S doped ZnO-NiO (a) Survey of S doped ZnO-NiO (b) S 2p (c) Zn (d) Ni (d) O.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/7774178795e37b7f480f2a90.png"},{"id":57496665,"identity":"9959204e-0263-4c93-b10d-b11cbe5ac237","added_by":"auto","created_at":"2024-05-31 12:49:40","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":265783,"visible":true,"origin":"","legend":"\u003cp\u003e(a) LSV Of OER (b) The corresponding histograms (c) Tafel Slope for OER (d) OER stability of S doped ZnO-NiO (e) TOFs of S doped ZnO-NiO, S ZnO-NiO and IrO\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/b5c0ee8980a589571d5fdeaa.png"},{"id":57496662,"identity":"c14b7d5f-6c52-4f4f-88bb-49a0a6628e33","added_by":"auto","created_at":"2024-05-31 12:49:40","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":28307,"visible":true,"origin":"","legend":"\u003cp\u003e(a) CV of S doped ZnO-NiO (b) \u003cem\u003eC\u003c/em\u003e\u003csub\u003edl\u003c/sub\u003e of S doped ZnO-NiO, ZnO-NiO, and IrO\u003csub\u003e2\u003c/sub\u003e (c) EIS Of S doped ZnO-NiO, ZnO-NiO, and IrO\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/66f93253bbc99e3c75066cfb.png"},{"id":57497082,"identity":"e30be354-5409-4527-8681-697b974ca3b7","added_by":"auto","created_at":"2024-05-31 12:57:40","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":40841,"visible":true,"origin":"","legend":"\u003cp\u003eFigure 5-4 (a) LSV Of HER (b) The corresponding histograms (c) Tafel Slope for HER (d) HER stability of S doped ZnO-NiO (e) TOFs of S doped ZnO-NiO, S ZnO-NiO and Pt/C.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/4e10a57d5f196f9f1a412562.png"},{"id":57496667,"identity":"6c569bf6-6591-4417-ade6-0960d1c6b4d0","added_by":"auto","created_at":"2024-05-31 12:49:40","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":23515,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Polarization curve for overall water splitting in alkaline media (b) 10 hr. stability of two electrodes in alkaline media.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/09c289bd17716d3e3127dea2.png"},{"id":66096832,"identity":"8cc218c4-45ff-4bfa-a0ce-a8973b4eedee","added_by":"auto","created_at":"2024-10-07 16:10:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2364589,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4441679/v1/37e0f599-0f68-4878-8526-b3312850e7ad.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Sulfur doped Zinc Oxide-Nikel Oxide as Efficient Bifunctional Electrocatalyst for overall Water splitting","fulltext":[{"header":"Highlights","content":"\u003cul\u003e\n \u003cli\u003eS-doped ZnO-NiO showed excellent activity catalyst.\u003c/li\u003e\n \u003cli\u003eS exhibit excellent HER performance under alkaline condition.\u003c/li\u003e\n \u003cli\u003eThe Structural feature of ZnO is profit when added Sulfur increases the surface activity.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"1.Introduction","content":"\u003cp\u003eRenewable energy resources are the most sought-after area of study that is vital to the world's future and present \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. The sun, wind, geothermal energy, carbon dioxide, and other non-depleting sources are among the energy-producing options that can provide energy continually \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Using renewable resources to create power is a very practical method that involves splitting water into pure hydrogen and oxygen \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are two examples of reactions that combine to form water splitting.\u003c/p\u003e \u003cp\u003eFor both procedures to work as electrodes in practical applications, an electrocatalyst is required \u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. For the HER reaction, the electrocatalyst should follow a simple mechanism of low over potential \u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. OER activity, which requires a much greater potential than the HER reaction to transfer four electrons, is the main hindrance in the water splitting reaction. By utilizing many stages with a higher activation energy, this can be avoided \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. To solve this problem with electrocatalyst for OER, researchers proposed ruthenium and iridium oxide as a benchmark OER catalyst. The main drawback of binary benchmark catalysts is their expensive cost and limited availability when it comes to large-scale production \u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. Because transition metal oxides are present, there is a great interest among young researchers to investigate the creation of proportionate OER performance catalysts with excellent durability, cheap cost, and efficiency \u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. In addition to other transition metal oxides, several efforts are being made to develop nickel-based oxides and their composites as a suitable electrocatalyst to replace RuO\u003csub\u003e2\u003c/sub\u003e and IrO\u003csub\u003e2\u003c/sub\u003e OER catalysts. It has been strongly suggested that these binary oxides make excellent electrocatalysts \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. As a result, S, ZnO, and NiO are excellent, stable, abundant, and possess noteworthy electrochemical qualities when used as electromagnetic catalysts \u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. It is used in a variety of potential applications, such as super capacitors, batteries, sensors, and electrochromic devices. Because the shape of the electrocatalysts had a major impact on their electrochemical capabilities, scientists were able to generate a wide range of nanostructures, including porosity, nanoflower, nanorod, nanotube, and nanowire forms. It significantly affects the ability of the electrocatalysts to transfer charges \u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. Researchers have used a variety of synthetic methods to create these novel nanostructures. Among these, hydrothermal, sol-gel, co-precipitation, and other techniques are the most useful. The present work synthesizes S doped ZnO-NiO nanoclusters via a simple hydrothermal process. It is inexpensive, good for the environment, and easily adjusted \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. Because of the possible uses for nickel oxide nanostructures, several researchers have recently developed an interest in them. Testing for genotoxicity on nickel oxide nanoparticles has been demonstrated by Naresh Dumala and colleagues \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Wang et al. reported on nickel oxide nanoparticles for solar cell applications \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. Ensafi and colleagues worked on nickel nanoparticles supported on porous silicon flour for a nonenzymatic electrochemical glucose sensor \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. Sun and associates were investigating the application of nickel oxide nanoparticles in electrochromic materials \u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. Abdalla and associates employed multiwalled carbon nanotubes as sacrificial templates to produce nickel oxide nanotubes for usage in supercapacitor applications \u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. S doped ZnO-NiO was investigated by Abdur Rahman and colleagues using co-precipitation procedures \u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Liu et al. revealed the usage of S doped ZnO-NiO in water splitting \u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. Choudhary and colleagues synthesized NiO nanodisks for biological applications \u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e. Khan examined the characteristics of NiO nanofibers with his lab colleagues \u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e. Along with his collaborators, Aguilar created nanofluids based on NiO for use in solar applications \u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e. Soundararajan et al. described NiO nanoparticles relevant to lithium-ion batteries \u003csup\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e. Ni nanoparticles were created by Hu and his group for industrial use \u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe virgin, 20% Suphur Zn 10%, and Ni 10% nanocluster form is effectively manufactured for electrochemical OER applications using a straightforward hydrothermal technique. Improvement of the NiO nanostructure and the Zn\u003csup\u003e2+\u003c/sup\u003e ion function in the NiO host matrix have been discussed in detail. The physical and electrochemical characteristics of virgin NiO are correlated with the dopant effect. Based on estimation, the ideal dopant concentration of Zn\u003csup\u003e2+\u003c/sup\u003e with NiO host provided the greater electrochemical response, which has been extensively studied.\u003c/p\u003e \u003cp\u003eWe outlined the performance of a catalyst based on S, ZnO, and NiO for the OER reaction in basic medium since we are very inspired by these capabilities of transition metals. The new hybrid catalyst for the oxygen evolution process (OER) has been found to be more stable and active. The S doped ZnO-NiO for the activity of OER at low temperature towards effective overall water splitting was described in this study. When S-doped is doped with ZnO-NiO as a Sulfur source thiourea is the newly manufactured catalyst. Because Sulfur is added to transition metals, this Sulfur-doped catalyst (S doped ZnO-NiO) is very active toward OER. When compared to noble metal-based catalysts like IrO\u003csub\u003e2\u003c/sub\u003e, RuO\u003csub\u003e2\u003c/sub\u003e, and Pt/C, our newly synthesized catalyst exhibits higher OER activity. This catalyst's synthesis process is depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea.\u003c/p\u003e"},{"header":"2. Experimental detail","content":"\u003cp\u003eThiourea, as sulfur source, zinc nitrate hexahydrate (Zn (NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO) (\u0026ge;\u0026thinsp;99% purity, Sigma Aldrich), nickel nitrate hexahydrate (Ni (NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO) (\u0026ge;\u0026thinsp;98% purity, Merck), urea (CH\u003csub\u003e4\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003eO) (\u0026ge;\u0026thinsp;99% purity, Sigma Aldrich), and hexamethylenetetramine were among the analytical grade products obtained and utilized. The entire experiment was conducted with deionized water.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation of S doped ZnO-NiO nanocomposite\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe S doped ZnO-NiO composite was fabricated by hydrothermal method. 0.5 g thiourea was dissolved in 100 mL deionized water 0.1 M solutions each of nickel nitrate and zinc nitrate were prepared and mixed with thiourea solution under stirring. A 0.05 M solution of hexamethylenetetramine (HMTA) was prepared and mixed with metal nitrate solution in thiourea under stirring for 2 h. The mixture was heated in a 150 mL Teflon autoclave for 24 h at 180 \u0026deg;C. The formed precipitates were washed several times with ethanol and water, dried at 90 \u0026deg;C. The dried grained powder was then calcined at 400 \u0026deg;C for 2 h in a tube furnace \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. After calcination, the final product was collected and used for further characterization. Undoped ZnO-NiO nanocomposite was also prepared using the same experimental conditions and precursor materials without thiourea.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCharacterizations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter fabrication, the samples were characterized using different techniques. XRD was performed on a D/MAX-2500 X-ray diffractometer equipped with Cu K\u0026alpha; radiation at 40 kV and 40 mA at a scanning rate of 10 \u0026deg;C min\u003csup\u003e-1\u003c/sup\u003e. SEM images were obtained with Hitachi S-4800 FE-SEM. XPS was performed with a PHI-1600 equipped with Al K\u0026alpha; radiation. The binding energy was calibrated by the C1s peak (284.8 eV) of the contamination carbon. Surface area was examined using the BET instruments 3H-2000 PS2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eElectrochemical measurement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNickel foam was soaked in diluted HCl and allowed to dry at 60 \u0026deg;C overnight. 5\u0026ndash;10 mg of the fabricated sample was mixed with 20\u0026ndash;30 \u0026micro;L of Nafion binder, and 1 milliliter of 99% analytical grade ethanol. The mixture was sonicated for 10 min to form a homogenous paste. The homogenous paste was transferred loaded onto the surface of Ni-Foam using a micropipette. The foam was dried at ambient temperature and then annealed at 300 \u0026deg;C for 2 h. The activity of the electrocatalyst was measured using electrochemical workstation with the help of IVIUMSTAT workstation (IVIUM Technologies BV, Netherlands). The workstation was typically composed of three electrodes: a working electrode (catalyst on Ni-foam), a graphite rod as a counter electrode, and Ag/AgCl as a reference electrode. Each experiment was conducted in 1 M KOH solution at a scan rate of 5 mV s\u003csup\u003e-1\u003c/sup\u003e. Furthermore, the active surface area of the electrocatalyst was derived from (\u003cem\u003eC\u003c/em\u003e\u003csub\u003edl\u003c/sub\u003e) within 10\u0026ndash;90 mV s\u003csup\u003e-1\u003c/sup\u003e range. With a reversible hydrogen electrode, all the electrode potentials and LSV were adjusted. The following equation was used as a reference,\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eE\u003c/em\u003e \u003csub\u003eRHE\u003c/sub\u003e =E(Ag/AgCl)\u0026thinsp;+\u0026thinsp;0.059 pH\u0026thinsp;+\u0026thinsp;0.196 (5.1)\u003c/p\u003e\n\u003cp\u003eEach time, a pH meter was used to measure pH of the solution keeping 5 mV s\u003csup\u003e-1\u003c/sup\u003e as the LSV scan rate.\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Result and Discussion\u003c/h2\u003e\n \u003cp\u003eSulfur doped ZnO-NiO nanocomposite were produced using a simple hydrothermal technique. The XRD patterns of the electrocatalyst are shown in Fig.\u0026nbsp;5-\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb along with the standard cards sulfur (JCPD:04-007-2083), ZnO (JCPDS card No. 01-078-3315) and NiO (JCPDS card No. 01-071-1179). The crystal structure was investigated by exposing the prepared S doped NiO-ZnO samples. was observed as a set of sharp peaks at 2\u0026theta; S which is represented by 101, 300, 12\u0026thinsp;\u0026minus;\u0026thinsp;1, 21\u0026thinsp;\u0026minus;\u0026thinsp;2, 15\u0026thinsp;\u0026minus;\u0026thinsp;1, matched with sulfur (JCPD:04-007-2083), for ZnO at 2\u0026theta; 31, 34, 36, 47, 56, 67, 68, and 69 representing 100, 002, 102, 110, 200, 112, and 201 hkl planes of ZnO was observed. All these peaks are characteristic peaks of the hexagonal Wurtzite structure of ZnO. These peaks have been compared with standard diffraction data of ZnO (JCPDS card No. 01-078-3315). Another set of diffraction peaks at 2 thetas 37, 43, and 63 representing the 111, 200, and 220 hkl planes of NiO was noted in XRD patterns. These peaks are characteristic peaks of the Face-centered cubic structure of NiO (JCPDS card No. 01-071-1179) can see the XRD pattern in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb.\u003c/p\u003e\n \u003cp\u003eFigure \u0026minus;\u0026thinsp;1c demonstrates the SEM images of the fabricated electrocatalyst at different magnifications. Apparently, the sample presents a flower-like uniform morphology. The nanoparticles are uniformly distributed with very little tendency of agglomeration. At lower magnification, the formation of uniformly distributed S doped ZnO-NiO nanoflowers is clearly visible. Close inspection of the material under a little higher magnification reveals few structures that resemble bulk in addition to the flower. The EDX spectra of the sample in Figure \u0026minus;\u0026thinsp;2 demonstrates the signals of O, Zn, Ni, and S to verify the synthesis of S doped ZnO-NiO.\u003c/p\u003e\n \u003cp\u003eThe molar content of the elements S, Zn, O and Ni is approximately 43.88, 31.68, 9.59 and 1.559% respectively as shown in Table .1.\u003c/p\u003e\n \u003cp\u003eTable .1: Elemental Percentage of S, Zn, Ni, O and C\u0026nbsp;\u003c/p\u003e\n \u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eElement\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWeight %\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNet Weight\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAtomic weight\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e43.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eZn\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eThe uniform distribution of the elements in the fabricated nanocomposite is further confirmed from the elemental mapping of the constituent elements as shown in Figure \u0026minus;\u0026thinsp;1e.\u003c/p\u003e\n \u003cp\u003eThe existence of different components, chemical nature, and bonding in S doped ZnO-NiO were investigated using XPS as displayed in Figure \u0026minus;\u0026thinsp;3 The survey spectrum in Figure \u0026minus;\u0026thinsp;3a characterizes the presence of all the constituent elements such as S, Zn, Ni, and O. The introduction of sulfur is confirmed by two peaks of S 2p\u003csub\u003e1/2\u003c/sub\u003e and 2p\u003csub\u003e3/2\u003c/sub\u003e at 162.01 and 163.21 eV respectively in S figure \u0026minus;\u0026thinsp;3b, while sulfur oxide is revealed by a peak at 169.52 eV \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e. With a spin-orbit splitting of 23.07 eV, peaks at 1022.35 eV and 1045.43 eV correspond to Zn 2p\u003csub\u003e3/2\u003c/sub\u003e and Zn 2p\u003csub\u003e1/2\u003c/sub\u003e respectively as shown in Figure \u0026minus;\u0026thinsp;3c confirming a Zn\u003csup\u003e2+\u003c/sup\u003e oxidation state for Zn in the composite \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e. The high-resolution Ni XPS spectrum reveals five Ni-related peaks. The peaks at 855.95 eV and 873.51 eV respectively correspond to Ni 2p\u003csub\u003e3/2\u003c/sub\u003e and Ni 2p\u003csub\u003e1/2\u003c/sub\u003e, validating a Ni \u003csup\u003e2+\u003c/sup\u003e oxidation state as shown in Figure \u0026minus;\u0026thinsp;3d. The availability of the O 1s peak at 530.69 eV demonstrates the existence of lattice oxygen in the nanocomposite as shown in Figure \u0026minus;\u0026thinsp;3e \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. The XPS survey spectrum and high-resolution XPS spectra confirmed the existence of all the elements presented in the S doped ZnO-NiO composite.\u003c/p\u003e\n \u003cp\u003eFrom all this discussion, unique elemental compositions, chemical structures, and bonding characteristics of S@Zno-NiO can be assured. The spectrum data has revealed the existence of diverse oxidation states and bonding interactions among Sulfur, Zinc, Nickel, and Oxygen to confirm the complex nature of the catalyst\u0026apos;s composition. Furthermore, the exposed surface area of S@Zno-NiO was investigated by BET, and the definite surface area for all samples is shown in Table 2. The surface area of the Sulfur doped Zinc Oxide and Nickel Oxide is found to be 69 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which is greater than the individual surface area of ZnO-NiO (66 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in Table-2. This larger surface area of S@Zno-NiO is more beneficial for better electron transfer and can lead to better catalytic performance. Moreover, it is worth noting that S@Zno-NiO has a large surface area and can show better performance for HER and OER\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Electrocatalytic OER performance\u003c/h2\u003e\n \u003cp\u003eIn a 1 M KOH solution, we investigated the S doped binary oxides for OER. The OER polarization curves were recorded at a reduced scan rate (5 mV s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). The LSV of S doped ZnO-NiO, ZnO, NiO, and IrO\u003csub\u003e2\u003c/sub\u003e in alkaline environment at a current density of 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e are displayed in Figure \u0026minus;\u0026thinsp;4a.and the corresponding histograms Figure \u0026minus;\u0026thinsp;4b Compared to IrO\u003csub\u003e2\u003c/sub\u003e, the activity of S doped ZnO-NiO binary oxides is superior. A potential of 230 mV at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e is demonstrated by the synthesized catalyst, which performed better than the RHE value for IrO\u003csub\u003e2\u003c/sub\u003e (310 mV at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e) \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n \u003cp\u003eThis newly synthesized catalyst, containing S, ZnO, and NiO, provides more evidence that electrocatalysis is improving. In addition, a Tafel plot illustrating the connection between current density and overpotential is generated to explore the catalytic kinetics for OER. Figure \u0026minus;\u0026thinsp;4c displays a comparison of the Tafel slope values for each sample. Tafel slope values for S doped ZnO-NiO are determined to be 77 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 63 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, while IrO\u003csub\u003e2\u003c/sub\u003e shows only 115 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The increased conductivity of the Tafel slope supports improved OER. Less than 120 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is a more favorable Tafel slope value for OER \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e. The turnover frequency (TOF) is another essential factor in evaluating the better performance of OER \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/sup\u003e. At a potential of 230 mV, S doped ZnO-NiO has a TOF of 0.15 (s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), which is higher than IrO\u003csub\u003e2\u003c/sub\u003e. The superior performance of OER is demonstrated by the greater TOF value of S doped ZnO-NiO as shown in Figure \u0026minus;\u0026thinsp;4e.\u003c/p\u003e\n \u003cp\u003eAnother important parameter to analyze the kinetics of the catalytic process is the electrochemical impedance spectroscopy (EIS) which shows the charge transfer resistance in the nanocomposite. The fast electron transmission method is frequently associated with the smaller semicircle of EIS. A sizable semicircle and a greater charge transfer resistance of roughly 140 Ω are displayed by the ZnO-NiO. On the other hand, the resistance approaches 90 Ω when S is added. By simultaneously adding sulfur, the electron transfer throughout the catalytic process is frequently facilitated. It is notable that S doped ZnO-NiO of 90 Ω has a lower charge transfer resistance (Rct) than ZnO-NiO as demonstrated in Figure \u0026minus;\u0026thinsp;5c.\u003c/p\u003e\n \u003cp\u003eFurthermore, an electrocatalyst\u0026apos;s improved performance depends on its electrical conductivity and quantity of active sites \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/sup\u003e. Progressive activities are a result of the catalysts\u0026apos; improved active sites and increased conductivity. By serving as a conductive background for quicker electron transfer, the ZnO improves the catalytic properties of water splitting. As an additional parameter, the CV are shown in Figure \u0026minus;\u0026thinsp;5a at different scan rates (10\u0026ndash;80 mV s\u003csup\u003e-1\u003c/sup\u003e). Every CV curve boosts the \u003cem\u003eC\u003c/em\u003e\u003csub\u003edl\u003c/sub\u003e by representing a whole rectangular performance at every scan rate. The \u003cem\u003eC\u003c/em\u003e\u003csub\u003edl\u003c/sub\u003e normalizes the exchange\u0026apos;s current density and is directly correlated with the catalyst\u0026apos;s active site count, indicating increased catalytic activity \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/sup\u003e. As can be shown in Figures \u0026minus;\u0026thinsp;5b, the \u003cem\u003eC\u003c/em\u003e\u003csub\u003edl\u003c/sub\u003e value of our sample is 63 mA cm\u003csup\u003e-2\u003c/sup\u003e, which is noticeably higher than the values reported by any other synthetic sample. NiO had a higher current density, however adding ZnO produced more active sites.\u003c/p\u003e\n \u003cp\u003eAdditionally, the remarkable efficacy of S-doped ZnO-NiO is demonstrated by its stability, which is a crucial factor that confirmed the catalytic activity of the produced catalyst. The catalyst S doped ZnO-NiO provided better stability for 6 h in alkaline electrolyte and no significant changes are noted during this period.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Electrocatalytic HER performance\u003c/h2\u003e\n \u003cp\u003eTo evaluate the HER activity of samples, the HER polarization curves of S-doped ZnO-NiO, Zno-NiO and Pt/C were compared with those of a state-of-the-art and deposited with the binder. The HER profiles of S-doped ZnO-NiO, Zno-NiO and Pt/C are exhibited in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ea and the corresponding histogram Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003eb the electrochemical performance of the prepared material was demonstrated by measuring the overpotential. The observed Over Potential for S@Zno-NiO, ZnO-NiO, Pt/C 170 mV, 140 mV, and 180 mV respectively Our best sample, S@Zno-NiO, has a modest potential of 30 mV at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e for HER with a greater current density. The outcomes of HER initiatives correlate with commercial catalysts like Pt/C. The results showed that the performance of ZnO-NiO was lower (170 mV) at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e, both on Ni-foam and on the material itself. Additionally, transition metal alloy is essential for improving the HER \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n \u003cp\u003eTafel slopes were also calculated by using LSV data and shown in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ec which represents the stage in the electrocatalytic hydrogen generation process that establishes the rate and the likely mechanism for S@Zno-NiO, Zno-NiO, and Pt/C which were 97 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 92 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003csub\u003e,\u003c/sub\u003e and 30 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003csub\u003e,\u003c/sub\u003e respectively exhibit that it has excellent reaction kinetics and electron transfer efficiency for HER. Our novel bifunctional catalyst showed significant results.\u003c/p\u003e\n \u003cp\u003eThe turnover frequency (TOF) measurement for S-doped ZNo-NiO is also 1.01 s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e at 30 mV overpotential at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. This is significantly better than the (TOF) values shown in Figure \u0026minus;\u0026thinsp;6e for S doped ZnO-NiO, S ZnO-NiO and Pt/C.\u003c/p\u003e\n \u003cp\u003eA further essential component of the catalyst\u0026apos;s catalytic activity is its exceptional stability. Our best catalyst (S doped ZnO-NiO,) demonstrated HER stability throughout 5 h. The current range shown in Figure-6d is constant because there is no variation during this time. The entire mechanism underlying S doped ZnO-NiO \u0026apos; improved performance for both HER and OER is still unknown. Furthermore, it is anticipated that the catalyst\u0026apos;s performance has been improved by the ZnO, the addition of sulfur as an active metal, and the distinctive shape of the transition metal alloy. Additionally, ZnO and sulfur need to be able to connect with another substance \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e42\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e43\u003c/span\u003e]\u003c/sup\u003e. Table .2 Electrochemical activities for all samples.\u003c/p\u003e\n \u003cp\u003eTable.2 Electrochemical activities for S doped ZnO-NiO and ZnO-NiO.\u0026nbsp;\u003c/p\u003e\n \u003ctable id=\"Tabb\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eName of catalyst\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSurface area\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eOER at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOER at 50 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHER at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHER at 50 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTafel slope for OER\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTafel slope for HER\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWater Splitting at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eS-doped ZnO-NiO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69 m\u003csup\u003e2\u003c/sup\u003e g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e230 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e245 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18.6 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e77 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.49V\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eZnO-NiO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66 m\u003csup\u003e2\u003c/sup\u003e g-\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e310 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e280 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e160 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.5 mV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e63 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e92 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-------\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePt/C\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eIt is anticipated that sulfur\u0026apos;s valence shell electrons are incomplete; sulfur must connect with another molecule to finish the valence shell. An essential step for OER and HER is the absorption of the water molecules on the catalyst surface, which is facilitated by the presence of partially positive and partially negative ions. Additionally, the catalyst for water splitting was improved by a more excellent synergistic link between sulfur and Zno as well as NiO with a distinctive cylindrical structure. On the other hand, excellent performance for HER and OER is also anticipated from the catalyst due to its active surface area and readily available redox sites. Therefore, based on the earth-abundant metal electrocatalyst, S doped ZnO-NiO is a novel bifunctional electrocatalyst for energy conversion.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Electrocatalytic Water Splitting","content":"\u003cp\u003eThe S doped ZnO-NiO was further investigated as the same electrocatalyst on both anode and cathode electrodes with a two-electrode system to evaluate its performance for overall water-splitting reaction in 1 M KOH solution. As shown in figure \u0026minus;\u0026thinsp;7a and the corresponding histogram figure \u0026minus;\u0026thinsp;7b the LSV curve of S doped ZnO-NiO, the onset voltage for water-splitting is 1.49 V and 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e current density Remarkably, only a slight increase in the overpotential is seen after studying the durability of S doped ZnO-NiO for 10 h at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e we can see in figure \u0026minus;\u0026thinsp;7c. Because it has a higher current density, S doped ZnO-NiO are initially employed for overall water splitting. This might be because of the unfamiliar double electrode environment; however, after 30 min, it showed a consistent potential of 1.49 V at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e. Furthermore, we have compared our catalyst with other published catalyst the details are shown in Table .3\u003c/p\u003e\n\u003cp\u003eTable: .3 Summarized bifunctional electrocatalysts presented in alkaline media. Overpotentials and cell voltages other than at \u0026eta;\u003csub\u003e10\u003c/sub\u003e and 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e respectively are mentioned.\u0026nbsp;\u003c/p\u003e\n\u003ctable id=\"Tabc\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eElectrocatalyst\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSupport / Substrate\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eElectrolyte\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHER \u003cem\u003e\u0026eta;\u003c/em\u003e\u003csub\u003e10\u003c/sub\u003e (mV)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOER \u003cem\u003e\u0026eta;\u003c/em\u003e\u003csub\u003e10\u003c/sub\u003e (mV)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCell Voltage (V) at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRef\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eS doped ZnO-NiO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e230\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThis work\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Fe\u003csub\u003e2\u003c/sub\u003eB/NF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCr-FeNi-P\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e190\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e240\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi\u003csub\u003e0.82\u003c/sub\u003eCo\u003csub\u003e0.18\u003c/sub\u003eO\u003c/p\u003e\n \u003cp\u003e@C\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e320\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoOx /Ni\u003csub\u003e3\u003c/sub\u003eS\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e136\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFeP/Ni\u003csub\u003e2\u003c/sub\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e140\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e154\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCoMoNiS-NF-xy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e105\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e255\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNiFe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e236\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(Ni\u003csub\u003e0.33\u003c/sub\u003eFe\u003csub\u003e0.67\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e214\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e230\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFe-CoP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e227\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN-Ni\u003csub\u003e3\u003c/sub\u003eS\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNi-Foam\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 M KOH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e110\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e350\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003eThe outstanding catalytic activity and better stability of (S@Zno-NiO) on Ni-Foam are based on the following illustrious factors, sulfur and binary compound are highly reactive, and similarly, metallic oxide and binary oxide are extremely responsive towards\u003c/p\u003e\n\u003cp\u003eOER \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e44\u003c/span\u003e]\u003c/sup\u003e.Transition metal alloy is also reactive towards HER activities, here in our catalyst ZnO and NiO is presented in a unique morphological form, which is evidence for better activity for HER \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e45\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e47\u003c/span\u003e]\u003c/sup\u003e. The porous morphology of the Ni-foam electrode not only confirms easy contact of the surface-active sites with the electrolyte but also improved the OER and HER activities.\u003c/p\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eWe have effectively synthesized a hybrid electrocatalyst (S-doped-ZnO-NiO) for the Oxygen Evolution Reaction using a straightforward experimental approach that is also practical for common industrial use. Our hybrid catalyst exhibits long-term durability in alkaline electrolytes and has the potential to replace noble metal catalyst for the Oxygen Evolution Reaction (OER) at an overpotential of 230 mV at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. Furthermore, this work offers a safe and simple method to use this electrocatalyst for industrial application in addition to a stable and effective low-cost electrocatalyst for OER.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWang Yong conceived the project, designed the experiments, intercepted the data, and finalized the manuscript. The first draft of the manuscript was written by Faiq Saeed, and. Samia Faiq Saeed performed all the electrochemical measurements and recorded the X.R.D. data Samia Provided SEM/EDS images and analysis. Faiq Saeed provided the XPS data and analysis. All authors revised and commented on the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of competing interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe acknowledge the support from National Natural Science Foundation of China (22274109, 21976131).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eD. Aboelela, H. Saleh, A.M. Attia, Y. Elhenawy, T. Majozi, M. 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Mater. \u003cb\u003e30\u003c/b\u003e(27), 1800140 (2018)\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"electrocatalysis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ecat","sideBox":"Learn more about [Electrocatalysis](http://link.springer.com/journal/12667)","snPcode":"12678","submissionUrl":"https://submission.nature.com/new-submission/12678/3","title":"Electrocatalysis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Sulfur Doped ZnO-NiO, OER, HER, Water Splitting","lastPublishedDoi":"10.21203/rs.3.rs-4441679/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4441679/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA mixed Sulfur-doped zinc oxide-nickel oxide nanocomposite electrocatalyst for oxygen evolution reaction (OER) was prepared. By hydrothermal method, we prepared a high-efficiency OER electrocatalyst doped with zinc oxide and nickel oxide. By applying different characterizations, the material was proven to be a new phase of (S-doped-ZnO-NiO). S-doped ZnO-NiO, ZnO-NiO did not show excellent performance. At 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, the generation potential of OER is 1.45 V and that of HER is -0.04 V. This unique morphology results in better OER performance of 240 mV at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e in the KOH electrolyte, and similarly, the S-doped ZnO-NiO shows us excellent long-term stability in alkaline media with a small Tafel slope (77 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). S-doped ZnO-NiO hybrid catalysts offer great potential for electrochemical devices due to their low cost and high activity. we have successfully constructed an electrocatalyst with the dual functions of HER and OER, which can achieve efficient water splitting.\u003c/p\u003e","manuscriptTitle":"Sulfur doped Zinc Oxide-Nikel Oxide as Efficient Bifunctional Electrocatalyst for overall Water splitting","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-31 12:49:36","doi":"10.21203/rs.3.rs-4441679/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-07T11:06:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-11T12:17:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"325734932564319935596854600002529162011","date":"2024-05-30T14:57:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"39861776569149592958593784373393245302","date":"2024-05-30T07:12:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-30T05:05:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-22T15:28:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-05-21T06:46:22+00:00","index":"","fulltext":""},{"type":"submitted","content":"Electrocatalysis","date":"2024-05-18T15:40:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"electrocatalysis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ecat","sideBox":"Learn more about [Electrocatalysis](http://link.springer.com/journal/12667)","snPcode":"12678","submissionUrl":"https://submission.nature.com/new-submission/12678/3","title":"Electrocatalysis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0c853544-7b57-4753-a247-a8796dc01c85","owner":[],"postedDate":"May 31st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-07T16:02:04+00:00","versionOfRecord":{"articleIdentity":"rs-4441679","link":"https://doi.org/10.1007/s12678-024-00896-5","journal":{"identity":"electrocatalysis","isVorOnly":false,"title":"Electrocatalysis"},"publishedOn":"2024-10-01 15:57:39","publishedOnDateReadable":"October 1st, 2024"},"versionCreatedAt":"2024-05-31 12:49:36","video":"","vorDoi":"10.1007/s12678-024-00896-5","vorDoiUrl":"https://doi.org/10.1007/s12678-024-00896-5","workflowStages":[]},"version":"v1","identity":"rs-4441679","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4441679","identity":"rs-4441679","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}