Research on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction

Research on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction | 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 Research on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction Mingyu Yu, Jiao Liu, Mandula Huhe, Zhenhuan Ma, Xiangfeng Meng, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6398975/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 Ni₂P catalysts with different crystallinities in the oxygen evolution reaction (OER) and their effects on the catalytic performance were studied. The mechanism of enhancing the OER activity by the surface structure of the catalysts was explored, and Ni₂P catalysts with different crystallinities were synthesized via the hydrothermal method. The crystal layouts, morphological transformations, and electrochemical properties of the catalysts were analyzed by XRD, SEM, XPS, EIS, EPR, and electrochemical tests. The relationship between the formation of oxygen vacancies and the OER performance was investigated by simulating the reconstruction of the catalyst surface during potentiostatic discharge operation. The results show that Ni₂P catalysts with different crystallinities exhibit different surface reconstruction behaviors during the discharge process. In particular, more oxygen vacancies are derived on the surface of the LC-Ni₂P catalyst, which greatly improves the OER activity. In addition, the lower LSV overpotential significantly enhances the OER performance of the catalyst. The discharge process actively promotes the generation of oxygen vacancies and accelerates the charge transfer rate. The conclusions indicate that the surface reconstruction process and the formation of oxygen vacancies are the key factors for improving the OER performance of Ni₂P catalysts. Discharging in the low potential region can induce the formation of oxygen vacancies, thus enhancing the catalytic ability of the catalyst. 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 series of issues such as the energy crisis and environmental pollution have severely affected the sustainable development of humanity, making it extremely urgent to construct a green and low-carbon energy system[ 1 ]. With the continuous growth of the global demand for clean energy, hydrogen energy, as a high-quality secondary energy source, is receiving increasing attention. Hydrogen energy is an ideal sustainable energy source with zero carbon emissions, boasting advantages such as a high energy density (approximately 143 MJ/kg), cleanliness and no pollution, ease of storage and transportation, and convenience for renormalization. It is hailed as the "ultimate energy source" of the 21st century, capable of replacing fossil fuels in various scenarios, promoting deep decarbonization in industries, transportation, construction, power generation, metallurgy, and other fields. It is expected to address the increasingly severe environmental and energy problems[ 2 ] In the current hydrogen production processes, the overall water electrolysis using renewable surplus electricity is an effective and sustainable green hydrogen production solution. There are four ways to obtain green hydrogen through electrolyzing water with surplus green electricity generated from solar and wind energy: alkaline water electrolysis (AWE)[ 3 ], proton exchange membrane acidic water electrolysis (PEMWE)[ 4 ], solid oxide water electrolysis (SOWE)[ 5 ], and photo-assisted water electrolysis (PWE)[ 6 ]. Among them, the AWE technology was discovered the earliest and has relatively mature industrialization. However, it suffers from problems such as low production efficiency and high power consumption costs, and lacks market competitiveness compared with the traditional coal chemical industry for producing grey hydrogen[ 7 ]. Therefore, it is imperative to improve the efficiency and reduce the cost of hydrogen production by water electrolysis.The overall water electrolysis process is divided into two half-reactions, namely the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. The HER is a 2-electron transfer process, while the OER is a 4-electron coupled reaction[ 8 ]. As is well known, the OER with slow kinetics seriously hinders the effective conversion of energy. Therefore, the development of economical, efficient, and stable electrode catalysts is of great significance for achieving the goal of "cost reduction and efficiency improvement" of water electrolysis technology. Currently, the commercially available highly active hydrogen evolution catalyst and oxygen evolution catalyst are platinum carbon (Pt/C), iridium dioxide (IrO₂), and ruthenium dioxide (RuO₂), respectively. The scarcity and high cost of these precious metal AWE electrode materials severely limit the large-scale application of industrial alkaline water electrolysis[ 9 , 10 ]. In order to reduce the cost of electrodes, in recent decades, researchers have begun to focus on non-noble metal-based OER catalysts, including transition metal oxides, sulfides, phosphides, nitrides, etc.,as well as transition metal-based OER catalysts such as hydroxides and oxyhydroxides. Some of them even exhibit activities surpassing those of the benchmark catalysts Pt/C, IrO₂, and RuO₂ [ 11 – 16 ]. Among numerous catalysts, Ni-based catalysts, due to their unique physical and chemical properties, especially Ni₂P, have demonstrated great development potential in the field of industrial alkaline water electrocatalysis[ 17 , 18 ] [ 19 ]. However, the catalytic activity of Ni₂P is often restricted by the stability of the surface structure and the distribution of active sites [ 20 ]. Studies have shown that the low potential region can induce the reconstruction of the catalyst surface, thereby improving the catalytic activity [ 21 ]. To address this issue, researchers have started to focus on the surface reconstruction of catalysts during the implementation of electrochemical reactions, especially during the discharge operation stage in the low potential region. By adjusting the crystallinity of Ni₂P, its surface structure and catalytic performance can be significantly influenced [ 22 ]. Ni₂P with different crystallinities exhibits different surface reconstruction behaviors during the discharge stage [ 23 – 26 ]. Therefore, in this study, we aim to systematically explore the behaviors of Ni₂P with different crystallinities during the surface reconstruction process in the low potential region, with a focus on its influence on the OER activity. Through the synthesis and characterization of Ni₂P with different crystallinities, combined with electrochemical explorations, we strive to reveal the relationship between the surface reconstruction of the catalyst and the formation of oxygen vacancies, providing a theoretical basis for the optimized design of Ni-based catalysts. 2. Synthesis of Ni₂P In this paper, the Ni₂P catalyst was synthesized through a hydrothermal reaction and calcination process. The key to the synthesis is to prepare Ni₂P with different crystallinities. As depicted in Fig. 1 , initially, 0.291 g of Ni(NO₃)₂·6H₂O, 0.093 g of NH₄F, and 0.3 g of urea were added to 20 mL of deionized water, and the mixture was stirred thoroughly to form a precursor solution. Subsequently, the solution, together with a piece of carbon paper with dimensions of 2×2.5 cm.T, was placed into a 45 mL high-temperature hydrothermal reactor. The solution was then placed in an oven at 120°C for 6 hours. After the reaction was completed, the solution was cooled down to room temperature. The carbon paper was taken out, rinsed three times with deionized water to remove the excess precursor, and then dried at room temperature [ 27 – 29 ]. Next, to obtain Ni₂P with varying crystallinities, the dried precursor was transferred into a quartz glass tube, and 500 mg of NaH₂PO₂ was placed upstream as the phosphorus source. This operation was carried out under an argon atmosphere at a heating rate of 10°C/min. The mixture was successively calcined at 400°C, 500°C, and 600°C for 40 minutes each, and finally, the mixture was allowed to cool naturally to room temperature. By means of this method, three types of Ni₂P with different crystallinities were successfully prepared. Specifically, the sample prepared at 400°C was amorphous Ni₂P, the sample synthesized at 500°C was Ni₂P with low crystallinity, and the sample produced at 600°C was Ni₂P with high crystallinity. This synthesis approach facilitated the production of Ni₂P with diverse crystallinities, laying a material foundation for the subsequent catalytic performance tests [ 30 – 33 ]. 3. Results and Discussion 3.1 Crystal Structure and Morphology Analysis 3.1. Results of XRD Analysis The Ni₂P samples synthesized at different calcination temperatures were analyzed by X-ray diffraction (XRD) method. As shown in Fig. 2 , among the three samples, the diffraction peaks at 26.4° and 54.5° match those of the base carbon paper material. No other characteristic peaks were observed for the Ni₂P synthesized at 400°C, confirming its amorphous structure. When the calcination temperature was increased to 500°C and 600°C, multiple characteristic peaks appeared in the XRD spectra, located at 40.8°, 44.6°, 47.3°, 54.3°, and 74.7°, respectively. These peaks correspond to the (111), (201), (210), (300), and (400) crystal planes of Ni₂P as shown in (JCPDS No. 03-0953). Combined with the calculation of the grain size using the Scherrer formula, it is indicated that the Ni₂P synthesized at 500°C has a smaller grain size and slightly poorer crystallinity, while the Ni₂P synthesized at 600°C has larger grains, suggesting higher crystallinity [ 34 – 37 ]. 3.1.2 Results of HRTEM Analysis The analysis by High-Resolution Transmission Electron Microscopy (HRTEM) further confirmed the findings of the XRD analysis. For the amorphous Ni₂P, no distinct lattice fringes were detected, which is consistent with the characteristics of its amorphous structure (Fig. 3 a). For the low-crystallinity Ni₂P (LC-Ni₂P), lattice fringes could be observed within a small area. The observed lattice spacings were 0.226 nm and 0.262 nm, corresponding to the (111) and (210) crystal planes, respectively (Fig. 3 b). As for the highly crystalline Ni₂P (HC-Ni₂P), clear lattice fringes could be seen over a larger area, and the detected lattice spacing was 0.261 nm, which can be attributed to the (210) crystal plane of Ni₂P (Fig. 3 c). 3.1.3. Results of SEM Morphology Analysis The morphological analysis by Scanning Electron Microscopy (SEM) shows that all three catalysts exhibit a typical nanosheet morphology (Fig. 3d 1 , e 1 , f 1 ), with diameters of 5.96、 3.66, and 4.09 µm, respectively. A-Ni₂P and LC-Ni₂P display smooth surfaces under high magnification (Fig. 3d 2 , e 2 ). The surface of HC-Ni₂P is composed of nanoparticles of small size, with different pore structures between the particles (Fig. 3f 2 ). These differences in morphology are closely related to their crystallinities, which further analyzes the structural characteristics of Ni₂P with different crystallinities. 3.2. Electrochemical Performance Tests 3.2.1. Analysis of LSV Curves Linear Sweep Voltammetry (LSV) is a commonly used method to explore the electrochemical performance of catalysts. The OER performance of Ni₂P catalysts with different crystallinities was studied by conducting LSV scans on them. In the experiment, the Ni₂P catalysts were initially subjected to several LSV scans within a high potential range of 0.6 to 1.4 V to gradually assist in charging the catalysts. From the observation of the LSV curves(Figure 4 ), it can be seen that the current densities of the three Ni₂P catalysts change with the variation of the starting and ending points of the scan, demonstrating the differences in the behavior of the catalysts at different potentials[ 38 ]. Specifically, when the starting point of the LSV scan shifts from 0.1 V to 0.6 V, the surface of the catalyst undergoes discharge, which is reflected in the appearance of a negative current, but the current density changes little within the corresponding high potential range. By reversing the starting order of the LSV, it was found that the current densities of the three catalysts continuously increase during the scanning process, indicating that a lower LSV starting potential will have a significant impact on the OER performance of the catalyst. Table 1 shows the changes in the current density during the LSV scans at different starting points. It can be seen that as the starting potential decreases, the growth rate of the current density at 1.4 V gradually increases, suggesting that a low starting potential is beneficial to improving the OER performance of the catalyst. Table 1 Changes in Current Density during LSV Scans at Different Starting Points Starting potential A -Ni 2 P Current density LC-Ni 2 P Current density HC-Ni 2 P Current density 0.1 V 2.5 mA cm -2 4.1 mA cm -2 5.3 mA cm -2 0.2 V 3.0 mA cm -2 4.5 mA cm -2 5.7 mA cm -2 0.3 V 3.4 mA cm -2 4.8 mA cm -2 6.0 mA cm -2 0.4 V 3.9 mA cm -2 5.2 mA cm -2 6.3 mA cm -2 0.5 V 4.2 mA cm -2 5.5 mA cm -2 6.5 mA cm -2 0.6 V 4.5 mA cm -2 5.9 mA cm -2 6.8 mA cm -2 6.8 3.2.2 Relationship between the Improvement of Electrochemical Performance and the LSV Starting Potential Studies have shown that the starting potential of the LSV scan has a significant impact on the OER performance of the catalyst. In the experiment, for Ni₂P catalysts with different crystallinities, the influence of different LSV scan starting points on the improvement of catalyst performance was tested. Through analysis, it was found that a lower LSV scan starting point (such as 0.1 V) can significantly increase the current density of the catalyst during the OER process[ 39 – 41 ]. As shown in Fig. 5 , special emphasis should be placed on LC-Ni₂P. The LSV scan with a lower starting potential not only triggers an increase in the current density but also stimulates the structural reconstruction of the catalyst surface, generating more active sites. This indicates that a low starting potential makes it easier for the catalyst to release charges and exert its effect, thereby promoting the catalytic activity. Table 2 shows the growth count of the current density at 1.4 V under different starting potentials. The data shows that as the LSV starting potential gradually decreases, the increase in the catalyst current density becomes more obvious, and the increase amplitude of LC-Ni₂P is the largest. Table 2 Increase in Current Density at 1.4 V under Different Starting Potentials Starting potential A -Ni 2 P current density improvement LC-Ni 2 P current density improvement HC-Ni 2 P current density improvement 0.1 V 1.2 mA cm -2 2.3 mA cm -2 3.2 mA cm -2 0.2 V 1.5 mA cm -2 2.7 mA cm -2 3.5 mA cm -2 0.3 V 1.8 mA cm -2 3.0 mA cm -2 3.8 mA cm -2 0.4 V 2.0 mA cm -2 3.2 mA cm -2 4.0 mA cm -2 0.5 V 2.3 mA cm -2 3.5 mA cm -2 4.2 mA cm -2 0.6 V 2.5 mA cm -2 3.7 mA cm -2 4.4 mA cm -2 3.2.3. Electrochemical Impedance Spectroscopy Analysis Electrochemical Impedance Spectroscopy (EIS) tests were carried out to study the charge transfer process and reaction kinetics of the catalysts. In existing research, EIS was used to investigate the charge transfer characteristics of Ni₂P catalysts with different crystallinities during the OER reaction. In the experiment, after the three Ni₂P catalysts were discharged at a high potential, the EIS test results showed that the discharge process significantly reduced the charge transfer resistance of the catalysts. Especially for the LC-Ni₂P sample, the charge transfer rate increased significantly, and the Rct value decreased the most, indicating that discharging in the low potential region can significantly improve the charge transfer ability of the catalyst surface, thus enhancing the catalytic activity[ 42 – 44 ]. Table 3 lists the changes in the Rct values of the three Ni₂P catalysts after potentiostatic discharge. When the discharge potential decreased slowly, the Rct of the three catalysts decreased significantly. In particular, when a potentiostatic discharge of 0.05 V was used, LC-Ni₂P showed a very obvious decrease in Rct, as specifically shown in Fig. 6 , Figure 7, and Figure 8. Table 3 Changes in RCT Values of Three Ni₂P Catalysts after Potentiostatic Discharge Discharge potential A -Ni 2 P Rct LC-Ni 2 P Rct HC-Ni 2 P Rct 0.05V 28.6Ω·cm² 19.5Ω·cm² 17.3Ω·cm² 0.15V 25.3Ω·cm² 17.8Ω·cm² 15.4Ω·cm² 0.25V 23.1Ω·cm² 15.2Ω·cm² 13.7Ω·cm² 0.35V 20.8Ω·cm² 13.1Ω·cm² 12.1Ω·cm² 0.45V 18.6Ω·cm² 10.6Ω·cm² 09.5Ω·cm² 0.55V 16.3Ω·cm² 09.2Ω·cm² 08.4Ω·cm² 3.3. The Influence of the Potentiostatic Discharge Process on the OER Performance of the Catalyst 3.3.1. Effects of constant potential discharge time on OER activity The potentiostatic discharge time has a significant impact on the activity of the Oxygen Evolution Reaction (OER) catalyst. During the potentiostatic discharge (0.05 V, 100 s) process, the morphology of the catalyst has changed remarkably. As can be observed from the SEM images (Fig. 9 ), especially for the HC-Ni₂P electrode, the surface has transformed from a sheet-like structure into a rough surface layer formed by fine nanoparticles, indicating that prolonging the discharge time is conducive to the reconstruction of the surface structure[ 45 , 46 ]. 3.3.2 Ionization Discharge Effects on Catalysts: Raman and EPR Analysis Using Raman spectroscopy and EPR techniques, significant insights into the effects of ionization discharge on catalyst surface structures have been gained. In Raman spectra(Figure 10a), the peak at 1300 cm -1 for A-Ni 2 P, LC-Ni 2 P, and HC-Ni 2 P is attributed to carbon paper. A new peak at 500 cm -1 emerges during constant potential discharge experiments, resulting from Ni-O stretching vibrations at high potentials. This indicates the formation of nickel oxide on the catalyst surface[ 47 ]. EPR spectra reveal the presence of unpaired electrons, with similar peak intensities and a consistent g-value of 2.002 across A-Ni 2 P, LC-Ni 2 P and HC-Ni 2 P, suggesting a commonality of oxygen vacancies. After constant potential discharge, the EPR spectra for the Ni 2 P types show increased peak intensities༈Figure 10c༉, particularly for LC-Ni 2 P at -0.05 V, indicating an accumulation of oxygen vacancies. This enhancement in oxygen vacancies correlates with improved catalyst performance, particularly in increasing OER activity[ 48 , 49 ]. 3.3.3 XPS analysis of the constant discharge process XPS analysis shows (Fig. 10b-d、f-h) that the Ni-P bond in the Ni₂P spectrum disappears and the Ni-O bond is strengthened after the discharge, indicating that the degree of oxidation of the surface nickel increases during the discharge process. Eventually, nickel oxide rather than phosphide is mainly formed on the catalyst surface. In contrast, there are no significant changes in the surface morphology and crystal structure of the A-Ni₂P and LC-Ni₂P electrodes after potentiostatic discharge. This difference suggests that a longer potentiostatic discharge time can promote the xidation reaction on the catalyst surface, thereby improving the OER activity of the catalyst[ 46 , 50 – 52 ]. 3.4. Surface Reconstruction and Formation of Oxygen Vacancies 3.4.1. Influence of the Discharge Process on the Formation of Oxygen Vacancies The discharge process plays a crucial role in the formation of oxygen vacancies in the catalyst. Under the given potentiostatic discharge conditions, electrochemical rearrangement occurs on the catalyst surface, leading to the formation of more oxygen vacancies. As shown in Fig. 11 a, the EPR analysis indicates that after potentiostatic discharge, the number of oxygen vacancies in the three Ni₂P catalysts increases slightly, and the peak intensity of the LC-Ni₂P catalyst shows an extremely obvious increase, suggesting that more oxygen vacancies are generated on its catalyst surface. The increase in oxygen vacancies can enhance the OER activity of the catalyst. This is because oxygen vacancies can optimize the electron transfer ability of the catalyst and drive the decomposition process of oxygen molecules, thus promoting the OER reaction. In addition, the finite element simulation results show that during the advancing stage of the discharge process, the greater the charge number of the electrode, the more oxygen vacancies are generated, which further illustrates the influence of the discharge process on the formation of oxygen vacancies. 3.4.2. Charge Transfer and Capacitance Analysis Charge transfer and capacitance analysis play a crucial role in understanding the improvement of catalyst performance. Different catalysts have different capacitance values during the discharge process. The capacitance differences among A-Ni₂P, LC-Ni₂P, and HC-Ni₂P are closely related to their surface charge accumulation capabilities. Catalysts with larger capacitances can achieve charge accumulation more quickly, thereby accelerating the discharge. This process will affect the charge distribution on the catalyst surface and the generation of oxygen vacancies. The results of the CP curve indicate that catalysts with larger capacitances discharge faster in the low potential region, can more effectively generate oxygen vacancies, and drive the redox reaction. Therefore, the increase in capacitance can promote the improvement of the catalyst surface structure and enhance the activity of the catalyst in the OER reaction[ 53 , 54 ]. 3.4.3. Simulation of the Discharge Process in the High Potential Region Simulating the discharge process in the high potential region through the finite element method helps to conduct an in-depth study of the distribution of charges on the catalyst surface and the formation rules of oxygen vacancies during the discharge process. The simulation results show (as in Fig. 11 c-e) that when the discharge proceeds, the oxygen vacancies formed in the catalyst gradually increase with the increase of the discharge time, and the content of oxygen vacancies in the longitudinal direction of the electrode gradually decreases. The greater the total charge number contained in the electrode, the faster the discharge rate during the discharge process, and the faster the electrode potential drops to the potential plateau, resulting in the generation of more oxygen vacancies. In addition, the simulation also indicates that the rapid discharge situation caused by a high charge number will not only generate more oxygen vacancies but also significantly exacerbate the difference in the concentration gradient of oxygen vacancies, thereby further enhancing the OER activity of the catalyst. 4. Conclusion This study systematically explored the surface reconstruction of Ni₂P catalysts with different crystallinities during the Oxygen Evolution Reaction (OER) and the underlying mechanism for the improvement of their catalytic performance. After potentiostatic discharge, the formation of oxides on the catalyst surface and the generation of oxygen vacancies significantly enhanced its electrochemical performance. Based on the above - mentioned multi - dimensional data analysis and research, it is shown that the discharge process in the low - potential region promotes the surface reconstruction of the catalyst. Notably, the low - crystallinity Ni₂P (LC - Ni₂P) catalyst exhibits more oxygen vacancies after discharge, thus enhancing its OER activity. In addition, capacitance and charge transfer analyses further reveal the relationship between the discharge characteristics of the catalyst at different potentials and its catalytic performance. The simulation results also show that a larger capacitance and rapid discharge can more effectively generate oxygen vacancies and enhance the OER activity of the catalyst. In future research, it is possible to further explore the surface reconstruction processes under different catalyst materials and electrochemical conditions. By optimizing the catalyst structure, the OER performance is expected to be further improved, providing theoretical support and practical references for the efficient catalysis of clean energy. Declarations Funding This research was funded by the (2024) College Students' Innovation and Entrepreneurship Training Program of Jining Normal University (Project No.: X (2024) 11427028) and the 2024 Ordos City Social Science Research Project (Project Number: 2024S381). Competing interests The authors declare no competing interests. Ethical Approval Not relevant. Consent for publication All authors have given their consent for the publication of this research. Author Contribution Mandula Huhe, Zhenhuan Ma and Xiangfeng Meng contributed equally to this work. Mingyu Yu : Involved in catalyst synthesis experiments and data collection. Mandula Huhe (co - first author): Optimized catalyst synthesis, led electrochemical tests, and analyzed data. Zhenhuan Ma (co - first author): Assisted in catalyst - related experiments and data recording. Xiangfeng Meng (co - first author): Contributed to research concept and data analysis guidance. Xu Kai: Responsible for the calibration and maintenance of experimental equipment to ensure the smooth progress of the experiment. Jiaxin Dong and Sibin Zhang : Participated in research planning and aided in electrochemical data analysis. Jiao Liu (corresponding author): Took overall responsibility for the research project, carefully guided the experimental design, strictly supervised the experimental process, controlled the quality of paper writing, and utilized personal resources to provide strong support for the project progress. Acknowledgement We are grateful to the funding programs and all team members. The (2024) College Students' Innovation and Entrepreneurship Training Program of Jining Normal University and the 2024 Ordos City Social Science Research Project provided financial support. Thanks also go to all team members for their hard work. References YANG X, SONG Y, WANG G, WANG W. 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A Cu-Cu2O/Ni2P Heterostructure for Efficient Tandem Catalysis of Electrosynthesis of Ammonia from Nitrate Reduction Reaction in Neutral Medium . Advanced Functional Materials,n/a(n/a): 2425459. (2025) HUANG Z, LIAO X, ZHANG W, HU J, GAO Q. Ceria-promoted reconstruction of Ni-based electrocatalysts toward efficient oxygen evolution . ACS Catalysis,12(22): 13951-60. (2022) LIU Y, QIN G, SONG M, HUANG Y, HUANG X. Strong interface effect on Ni2P/CeOx nanoparticles for high performance lithium-sulfur batteries . Nano Energy,133: 110508. (2025) REN J-T, CHEN L, WANG H-Y, TIAN W-W, SONG X-L, KONG Q-H, YUAN Z-Y. Synergistic Activation of Crystalline Ni2P and Amorphous NiMoO x for Efficient Water Splitting at High Current Densities . ACS Catalysis,13(14): 9792-805. (2023) CHU S, LI X, ZHOU X, PRINS R, WAQAS Q, WANG A, SHENG Q, HAO Q. Preparation of Ni 2 P Supported on Al 2 O 3 and B 2 O 3 Mixed Oxides by Temperature-Programmed Reduction of Phosphate Precursors with Low P/Ni Ratios . 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Fabricating of multi-interfacial charge transfer paths in the novel noble-metal-free Ni2P/ZnS/g-C3N4 ternary nanocomposite for enhanced charge separation and transfer for photocatalytic H2 generation . Journal of Alloys and Compounds,997: 174830. (2024) LI C, CHEN J, WU Y, CAO W, SANG S, WU Q, LIU H, LIU K. Enhanced oxygen evolution reaction activity of NiFe layered double hydroxide on nickel foam-reduced graphene oxide interfaces . International Journal of Hydrogen Energy,44(5): 2656-63. (2019) LI G, ANDERSON L, CHEN Y, PAN M, CHUANG P-Y A. New insights into evaluating catalyst activity and stability for oxygen evolution reactions in alkaline media . Sustainable Energy & Fuels,2(1): 237-51.2018 PAN Y, LIN Y, CHEN Y, LIU Y, LIU C. Cobalt phosphide-based electrocatalysts: synthesis and phase catalytic activity comparison for hydrogen evolution . Journal of Materials Chemistry A,4(13): 4745-54.2016 YU J, ZHONG H, ZHANG Q, WU C, ZHANG X, LI S, ZHAO Y, AN H, MA Y, YU Z. Unraveling the effect of local dopant environment on NiO6 octahedron perturbation for enhanced oxygen evolution activity . Applied Catalysis B: Environment and Energy,344: 123674. (2024) ZHAO X, CHEN X, WANG Y, SONG P, ZHANG Y. High-efficiency Ni–P catalysts in amorphous and crystalline states for the hydrogen evolution reaction . Sustainable Energy & Fuels,4(9): 4733-42. (2020) WANG D, XU Y, GUO X, FU Z, YANG Z, SUN W. Nickel foam as conductive substrate enhanced low-crystallinity two-dimensional iron hydrogen phosphate for oxygen evolution reaction . Journal of Alloys and Compounds,870: 159472. (2021) XIONG Y, ZENG W, AKASH A A, TANG Y, WEI D, LIU H, MAHMUD S. Effective Hydrogen Evolution of Nickel–Molybdenum–Phosphide Electrodeposited Nickel Foam Electrode . Catalysis Letters,155(4): 1-11. (2025) ZHAO T, SHEN X, WANG Y, HOCKING R K, LI Y, RONG C, DASTAFKAN K, SU Z, ZHAO C. In situ reconstruction of V‐doped Ni2P pre‐catalysts with tunable electronic structures for water oxidation . Advanced Functional Materials,31(25): 2100614. (2021) SUN C, JI S, WANG H, WANG X, WANG R. Effect of surface reconstruction induced by different electrochemical methods on hydrogen evolution performance of Ni2P array catalysts . International Journal of Hydrogen Energy,47(39): 17097-106. (2022) CHEN M, LIU D, QIAO L, ZHOU P, FENG J, NG K W, LIU Q, WANG S, PAN H. In-situ/operando Raman techniques for in-depth understanding on electrocatalysis . Chemical Engineering Journal,461: 141939. (2023) MIN K, KIM H, KU B, NA R, LEE J, BAECK S-H. Defect-rich Fe-doped Ni2P microflower with phosphorus vacancies as a high-performance electrocatalyst for oxygen evolution reaction . Journal of Industrial and Engineering Chemistry,122: 118-26. (2023) ZHOU Z, KONG Y, TAN H, HUANG Q, WANG C, PEI Z, WANG H, LIU Y, WANG Y, LI S. Cation‐vacancy‐enriched nickel phosphide for efficient electrosynthesis of hydrogen peroxides . Advanced Materials,34(16): 2106541. (2022) BERNASCONI R, KHALIL M I, CAKMAKCI D S, BEKTAS Y, NOBILI L, MAGAGNIN L, LENARDI C. Electrocatalytic layers for hydrogen evolution reaction based on nickel phosphides: cost-effective fabrication and XPS characterization . Journal of Materials Science,57(20): 9370-88. (2022) ELSENER B, ATZEI D, KRóLIKOWSKI A, ROSSI ALBERTINI V, SADUN C, CAMINITI R, ROSSI A. From chemical to structural order of electrodeposited Ni22P alloy: An XPS and EDXD study . Chemistry of materials,16(22): 4216-25. (2004) LIU G, HE D, YAO R, ZHAO Y, LI J. Enhancing the water oxidation activity of Ni2P nanocatalysts by iron-doping and electrochemical activation . Electrochimica Acta,253: 498-505. (2017) PAL S, AZAD U P, SINGH A K, KUMAR D, PRAKASH R. Studies on some spinel oxides based electrocatalysts for oxygen evolution and capacitive applications . Electrochimica Acta,320: 134584. (2019) JEON S S, KANG P W, KLINGENHOF M, LEE H, DIONIGI F, STRASSER P. Active surface area and intrinsic catalytic oxygen evolution reactivity of NiFe LDH at reactive electrode potentials using capacitances . Acs Catalysis,13(2): 1186-96. (2023) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6398975","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":452070233,"identity":"4287537d-df83-49e1-9f64-52266f2f682f","order_by":0,"name":"Mingyu Yu","email":"","orcid":"","institution":"Jining Normal University","correspondingAuthor":false,"prefix":"","firstName":"Mingyu","middleName":"","lastName":"Yu","suffix":""},{"id":452070235,"identity":"0d993ae8-0b15-409f-b817-58e74ad695d4","order_by":1,"name":"Jiao Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1UlEQVRIiWNgGAWjYBACeWb+jw8SKmyYIVw2IrQYtjcYG3w4k0aCFoYzB8wkZ7YdZiBeC+OMhGRjnjPn2c2lewwYPpQdZuCf3YBfC7tEwsHHPBW3mS3nnDFgnHHuMIPEnQOEbElsBtpym9ngRo4BMy/QhQYSCQRcdiOZTZq37RxEy1+itJw5xgb0/gGIFkZitBi29zADAzkZqCWt4GDPuXQeiRsEtMgz8zACo9Iu2eBG8sYHP8qs5fhnEHIYFCSDiANAzEOceiCwI1rlKBgFo2AUjDwAAIMjRBv5DezDAAAAAElFTkSuQmCC","orcid":"","institution":"Jining Normal University","correspondingAuthor":true,"prefix":"","firstName":"Jiao","middleName":"","lastName":"Liu","suffix":""},{"id":452070237,"identity":"d632a6ee-bd7a-4900-aa07-b7737d38bd5b","order_by":2,"name":"Mandula Huhe","email":"","orcid":"","institution":"Jining Normal University","correspondingAuthor":false,"prefix":"","firstName":"Mandula","middleName":"","lastName":"Huhe","suffix":""},{"id":452070243,"identity":"95f95586-14bf-4267-a36b-e547dfe4764c","order_by":3,"name":"Zhenhuan Ma","email":"","orcid":"","institution":"Jining Normal University","correspondingAuthor":false,"prefix":"","firstName":"Zhenhuan","middleName":"","lastName":"Ma","suffix":""},{"id":452070244,"identity":"a4f4ce82-a0c7-42dc-a736-a02985a7a71d","order_by":4,"name":"Xiangfeng Meng","email":"","orcid":"","institution":"Jining Normal University","correspondingAuthor":false,"prefix":"","firstName":"Xiangfeng","middleName":"","lastName":"Meng","suffix":""},{"id":452070245,"identity":"2b11e06b-3b74-46a3-8b92-183c15c3dd70","order_by":5,"name":"Kai Xu","email":"","orcid":"","institution":"国家管网集团浙江省天然气管网有限公司","correspondingAuthor":false,"prefix":"","firstName":"Kai","middleName":"","lastName":"Xu","suffix":""},{"id":452070246,"identity":"12c71882-34bf-4a24-8e44-bfbd8c18583c","order_by":6,"name":"Jiaxin Dong","email":"","orcid":"","institution":"Liaoning University","correspondingAuthor":false,"prefix":"","firstName":"Jiaxin","middleName":"","lastName":"Dong","suffix":""},{"id":452070247,"identity":"aa393905-b4f9-4f80-9d96-6efcd5d3fce4","order_by":7,"name":"Sibin Zhang","email":"","orcid":"","institution":"Inner Mongolia Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Sibin","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-04-08 04:08:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6398975/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6398975/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":82194345,"identity":"077659eb-d031-4de8-9a3b-9f75c0702558","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":86536,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the synthesis of Ni₂P with different crystallinities\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/08b0b05de472d022a8a24146.png"},{"id":82195717,"identity":"45fcadab-4b0a-4449-84e1-db257f56af3c","added_by":"auto","created_at":"2025-05-07 15:00:19","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":95065,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of X-ray diffraction (XRD) patterns of A-Ni₂P, LC-Ni₂P, and HC-Ni₂P.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/58c0586dacb95bd67ff7e267.png"},{"id":82194347,"identity":"e2219ce5-9bbe-4ae6-bc95-1e917859a653","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":956096,"visible":true,"origin":"","legend":"\u003cp\u003e(a-c) High-resolutiontransmissionelectronmicroscopy images of A-Ni2P,LC-Ni2P, and HC-Ni2P. (d-e)Scanning electron microscopy images of A-Ni2P, LC-Ni2P,and HC-Ni2P atdifferent magnifications.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/2a9dcc220b2e2ec7262eb763.png"},{"id":82194354,"identity":"769e4873-77a1-44ea-b46e-4b5da6e2243c","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1253127,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between catalyst performance and initial potential of LSV test.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/d8b405ff22ce1984441852bc.png"},{"id":82196297,"identity":"7b805491-1be7-46d0-a355-a99660559fe9","added_by":"auto","created_at":"2025-05-07 15:08:19","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":150416,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between LC-Ni₂P and LSV Overpotential\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/2d4bba7e77011ef14cbf61a3.png"},{"id":82194348,"identity":"8a5fe32c-bf10-4eed-9429-65af7b3b53a3","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":282023,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Electrochemical impedance spectroscopy of A-Ni₂P before and after potentiostatic discharge. (b) Fitted circuit model of the impedance data of A-Ni₂P\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/c27d99e505ed9b8659f4eeb0.png"},{"id":82195721,"identity":"d470963f-f88a-473a-8f17-4d289ae8ffce","added_by":"auto","created_at":"2025-05-07 15:00:19","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":251282,"visible":true,"origin":"","legend":"\u003cp\u003ea) Electrochemical impedance spectroscopy of LC-Ni₂P before and after potentiostatic discharge. (b) Fitted circuit model of the impedance data of LC-Ni₂P.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/f66843918c2de59864ea453f.png"},{"id":82194352,"identity":"05ffdfb9-dbbb-4e10-856e-043987dc3002","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":135149,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Electrochemical impedance spectroscopy of HC-Ni₂P before and after potentiostatic discharge. (b) Fitted circuit model of the impedance data of HC-Ni₂P.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/5aaa67ec56c50125cc15065c.png"},{"id":82194359,"identity":"31d16dab-c2e0-4632-b70f-43e53f0bc191","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":731423,"visible":true,"origin":"","legend":"\u003cp\u003eScanning Electron Microscopy (SEM) images of A-Ni₂P, LC-Ni₂P and HC-Ni₂P after potentiostatic discharge\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/c36a0593dbd161bb8d03898e.png"},{"id":82194362,"identity":"8d748cd2-3144-4946-ad78-48a6d199c653","added_by":"auto","created_at":"2025-05-07 14:52:19","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":1463424,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Comparison of Raman spectra of A-Ni₂P, LC-Ni₂P and HC-Ni₂P before and after potentiostatic discharge. (e) Comparison of Electron Paramagnetic Resonance (EPR) spectra of A-Ni₂P, LC-Ni₂P and HC-Ni₂P before and after potentiostatic discharge. (b-d, f-h) Ni 2p XPS spectra of the catalysts before and after potentiostatic discharge.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/46f04cd61075c598bb6e6979.png"},{"id":82196298,"identity":"eee1fc02-775e-4428-a59a-487cd0fbe876","added_by":"auto","created_at":"2025-05-07 15:08:19","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":258923,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic diagram of the formation of oxygen vacancies on the surface of Ni₂P with different crystallinities. (b) Discharge curves of the catalysts under different total loading conditions.(c-e) Simulation results of the longitudinal oxygen vacancy formation in the electrode as a function of discharge time.\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/3afefa3c429b8db53d6c4661.png"},{"id":83429688,"identity":"2ab36ff3-748f-4215-97fd-a00120dd2d89","added_by":"auto","created_at":"2025-05-26 06:33:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7415241,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6398975/v1/9e0fdc38-9191-4008-99fc-2e2c0d207d0a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eResearch on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eseries of issues such as the energy crisis and environmental pollution have severely affected the sustainable development of humanity, making it extremely urgent to construct a green and low-carbon energy system[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. With the continuous growth of the global demand for clean energy, hydrogen energy, as a high-quality secondary energy source, is receiving increasing attention. Hydrogen energy is an ideal sustainable energy source with zero carbon emissions, boasting advantages such as a high energy density (approximately 143 MJ/kg), cleanliness and no pollution, ease of storage and transportation, and convenience for renormalization. It is hailed as the \"ultimate energy source\" of the 21st century, capable of replacing fossil fuels in various scenarios, promoting deep decarbonization in industries, transportation, construction, power generation, metallurgy, and other fields. It is expected to address the increasingly severe environmental and energy problems[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn the current hydrogen production processes, the overall water electrolysis using renewable surplus electricity is an effective and sustainable green hydrogen production solution. There are four ways to obtain green hydrogen through electrolyzing water with surplus green electricity generated from solar and wind energy: alkaline water electrolysis (AWE)[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], proton exchange membrane acidic water electrolysis (PEMWE)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], solid oxide water electrolysis (SOWE)[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], and photo-assisted water electrolysis (PWE)[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Among them, the AWE technology was discovered the earliest and has relatively mature industrialization. However, it suffers from problems such as low production efficiency and high power consumption costs, and lacks market competitiveness compared with the traditional coal chemical industry for producing grey hydrogen[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Therefore, it is imperative to improve the efficiency and reduce the cost of hydrogen production by water electrolysis.The overall water electrolysis process is divided into two half-reactions, namely the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. The HER is a 2-electron transfer process, while the OER is a 4-electron coupled reaction[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. As is well known, the OER with slow kinetics seriously hinders the effective conversion of energy. Therefore, the development of economical, efficient, and stable electrode catalysts is of great significance for achieving the goal of \"cost reduction and efficiency improvement\" of water electrolysis technology.\u003c/p\u003e \u003cp\u003eCurrently, the commercially available highly active hydrogen evolution catalyst and oxygen evolution catalyst are platinum carbon (Pt/C), iridium dioxide (IrO₂), and ruthenium dioxide (RuO₂), respectively. The scarcity and high cost of these precious metal AWE electrode materials severely limit the large-scale application of industrial alkaline water electrolysis[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In order to reduce the cost of electrodes, in recent decades, researchers have begun to focus on non-noble metal-based OER catalysts, including transition metal oxides, sulfides, phosphides, nitrides, etc.,as well as transition metal-based OER catalysts such as hydroxides and oxyhydroxides. Some of them even exhibit activities surpassing those of the benchmark catalysts Pt/C, IrO₂, and RuO₂ [\u003cspan additionalcitationids=\"CR12 CR13 CR14 CR15\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong numerous catalysts, Ni-based catalysts, due to their unique physical and chemical properties, especially Ni₂P, have demonstrated great development potential in the field of industrial alkaline water electrocatalysis[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, the catalytic activity of Ni₂P is often restricted by the stability of the surface structure and the distribution of active sites [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Studies have shown that the low potential region can induce the reconstruction of the catalyst surface, thereby improving the catalytic activity [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo address this issue, researchers have started to focus on the surface reconstruction of catalysts during the implementation of electrochemical reactions, especially during the discharge operation stage in the low potential region. By adjusting the crystallinity of Ni₂P, its surface structure and catalytic performance can be significantly influenced [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Ni₂P with different crystallinities exhibits different surface reconstruction behaviors during the discharge stage [\u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Therefore, in this study, we aim to systematically explore the behaviors of Ni₂P with different crystallinities during the surface reconstruction process in the low potential region, with a focus on its influence on the OER activity. Through the synthesis and characterization of Ni₂P with different crystallinities, combined with electrochemical explorations, we strive to reveal the relationship between the surface reconstruction of the catalyst and the formation of oxygen vacancies, providing a theoretical basis for the optimized design of Ni-based catalysts.\u003c/p\u003e"},{"header":"2. Synthesis of Ni₂P","content":"\u003cp\u003eIn this paper, the Ni₂P catalyst was synthesized through a hydrothermal reaction and calcination process. The key to the synthesis is to prepare Ni₂P with different crystallinities. As depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, initially, 0.291 g of Ni(NO₃)₂\u0026middot;6H₂O, 0.093 g of NH₄F, and 0.3 g of urea were added to 20 mL of deionized water, and the mixture was stirred thoroughly to form a precursor solution. Subsequently, the solution, together with a piece of carbon paper with dimensions of 2\u0026times;2.5 cm.T, was placed into a 45 mL high-temperature hydrothermal reactor. The solution was then placed in an oven at 120\u0026deg;C for 6 hours. After the reaction was completed, the solution was cooled down to room temperature. The carbon paper was taken out, rinsed three times with deionized water to remove the excess precursor, and then dried at room temperature [\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Next, to obtain Ni₂P with varying crystallinities, the dried precursor was transferred into a quartz glass tube, and 500 mg of NaH₂PO₂ was placed upstream as the phosphorus source. This operation was carried out under an argon atmosphere at a heating rate of 10\u0026deg;C/min. The mixture was successively calcined at 400\u0026deg;C, 500\u0026deg;C, and 600\u0026deg;C for 40 minutes each, and finally, the mixture was allowed to cool naturally to room temperature. By means of this method, three types of Ni₂P with different crystallinities were successfully prepared. Specifically, the sample prepared at 400\u0026deg;C was amorphous Ni₂P, the sample synthesized at 500\u0026deg;C was Ni₂P with low crystallinity, and the sample produced at 600\u0026deg;C was Ni₂P with high crystallinity. This synthesis approach facilitated the production of Ni₂P with diverse crystallinities, laying a material foundation for the subsequent catalytic performance tests [\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Crystal Structure and Morphology Analysis\u003c/h2\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Results of XRD Analysis\u003c/h2\u003e \u003cp\u003eThe Ni₂P samples synthesized at different calcination temperatures were analyzed by X-ray diffraction (XRD) method. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, among the three samples, the diffraction peaks at 26.4\u0026deg; and 54.5\u0026deg; match those of the base carbon paper material. No other characteristic peaks were observed for the Ni₂P synthesized at 400\u0026deg;C, confirming its amorphous structure. When the calcination temperature was increased to 500\u0026deg;C and 600\u0026deg;C, multiple characteristic peaks appeared in the XRD spectra, located at 40.8\u0026deg;, 44.6\u0026deg;, 47.3\u0026deg;, 54.3\u0026deg;, and 74.7\u0026deg;, respectively. These peaks correspond to the (111), (201), (210), (300), and (400) crystal planes of Ni₂P as shown in (JCPDS No. 03-0953). Combined with the calculation of the grain size using the Scherrer formula, it is indicated that the Ni₂P synthesized at 500\u0026deg;C has a smaller grain size and slightly poorer crystallinity, while the Ni₂P synthesized at 600\u0026deg;C has larger grains, suggesting higher crystallinity [\u003cspan additionalcitationids=\"CR35 CR36\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2 Results of HRTEM Analysis\u003c/h2\u003e \u003cp\u003eThe analysis by High-Resolution Transmission Electron Microscopy (HRTEM) further confirmed the findings of the XRD analysis. For the amorphous Ni₂P, no distinct lattice fringes were detected, which is consistent with the characteristics of its amorphous structure (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). For the low-crystallinity Ni₂P (LC-Ni₂P), lattice fringes could be observed within a small area. The observed lattice spacings were 0.226 nm and 0.262 nm, corresponding to the (111) and (210) crystal planes, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb). As for the highly crystalline Ni₂P (HC-Ni₂P), clear lattice fringes could be seen over a larger area, and the detected lattice spacing was 0.261 nm, which can be attributed to the (210) crystal plane of Ni₂P (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e3.1.3. Results of SEM Morphology Analysis\u003c/h2\u003e \u003cp\u003eThe morphological analysis by Scanning Electron Microscopy (SEM) shows that all three catalysts exhibit a typical nanosheet morphology (Fig.\u0026nbsp;3d\u003csub\u003e1\u003c/sub\u003e, e\u003csub\u003e1\u003c/sub\u003e, f\u003csub\u003e1\u003c/sub\u003e), with diameters of 5.96、 3.66, and 4.09 \u0026micro;m, respectively. A-Ni₂P and LC-Ni₂P display smooth surfaces under high magnification (Fig.\u0026nbsp;3d\u003csub\u003e2\u003c/sub\u003e, e\u003csub\u003e2\u003c/sub\u003e). The surface of HC-Ni₂P is composed of nanoparticles of small size, with different pore structures between the particles (Fig.\u0026nbsp;3f\u003csub\u003e2\u003c/sub\u003e). These differences in morphology are closely related to their crystallinities, which further analyzes the structural characteristics of Ni₂P with different crystallinities.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Electrochemical Performance Tests\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1. Analysis of LSV Curves\u003c/h2\u003e \u003cp\u003eLinear Sweep Voltammetry (LSV) is a commonly used method to explore the electrochemical performance of catalysts. The OER performance of Ni₂P catalysts with different crystallinities was studied by conducting LSV scans on them. In the experiment, the Ni₂P catalysts were initially subjected to several LSV scans within a high potential range of 0.6 to 1.4 V to gradually assist in charging the catalysts. From the observation of the LSV curves(Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), it can be seen that the current densities of the three Ni₂P catalysts change with the variation of the starting and ending points of the scan, demonstrating the differences in the behavior of the catalysts at different potentials[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Specifically, when the\u003c/p\u003e \u003cp\u003estarting point of the LSV scan shifts from 0.1 V to 0.6 V, the surface of the catalyst undergoes discharge, which is reflected in the appearance of a negative current, but the current density changes little within the corresponding high potential range. By reversing the starting order of the LSV, it was found that the current densities of the three catalysts continuously increase during the scanning process, indicating that a lower LSV starting potential will have a significant impact on the OER performance of the catalyst. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the changes in the current density during the LSV scans at different starting points. It can be seen that as the starting potential decreases, the growth rate of the current density at 1.4 V gradually increases, suggesting that a low starting potential is beneficial to improving the OER performance of the catalyst.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChanges in Current Density during LSV Scans at Different Starting Points\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStarting potential\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA -Ni\u003csub\u003e2\u003c/sub\u003eP Current density\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLC-Ni\u003csub\u003e2\u003c/sub\u003eP Current density\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHC-Ni\u003csub\u003e2\u003c/sub\u003eP Current density\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.1 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.3 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.2 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.0 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.7 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.3 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.4 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.8 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.0 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.4 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.9 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.3 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.6 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.9 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.8 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e6.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2 Relationship between the Improvement of Electrochemical Performance and the LSV Starting Potential\u003c/h2\u003e \u003cp\u003eStudies have shown that the starting potential of the LSV scan has a significant impact on the OER performance of the catalyst. In the experiment, for Ni₂P catalysts with different crystallinities, the influence of different LSV scan starting points on the improvement of catalyst performance was tested. Through analysis, it was found that a lower LSV scan starting point (such as 0.1 V) can significantly increase the current density of the catalyst during the OER process[\u003cspan additionalcitationids=\"CR40\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e, special emphasis should be placed on LC-Ni₂P. The LSV scan with a lower starting potential not only triggers an increase in the current density but also stimulates the structural reconstruction of the catalyst surface, generating more active sites. This indicates that a low starting potential makes it easier for the catalyst to release charges and exert its effect, thereby promoting the catalytic activity. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the growth count of the current density at 1.4 V under different starting potentials. The data shows that as the LSV starting potential gradually decreases, the increase in the catalyst current density becomes more obvious, and the increase amplitude of LC-Ni₂P is the largest.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIncrease in Current Density at 1.4 V under Different Starting Potentials\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStarting potential\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA -Ni\u003csub\u003e2\u003c/sub\u003eP current density improvement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLC-Ni\u003csub\u003e2\u003c/sub\u003eP current density improvement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHC-Ni\u003csub\u003e2\u003c/sub\u003eP current density improvement\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.3 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.2 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.3 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.8 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.0 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.8 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.4 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.0 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.0 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.3 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.2 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.6 V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.7 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.4 mA cm\u003csup\u003e-2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e3.2.3. Electrochemical Impedance Spectroscopy Analysis\u003c/b\u003e Electrochemical Impedance Spectroscopy (EIS) tests were carried out to study the charge transfer process and reaction kinetics of the catalysts. In existing research, EIS was used to investigate the charge transfer characteristics of Ni₂P catalysts with different crystallinities during the OER reaction. In the experiment, after the three Ni₂P catalysts were discharged at a high potential, the EIS test results showed that the discharge process significantly reduced the charge transfer resistance of the catalysts. Especially for the LC-Ni₂P sample, the charge transfer rate increased significantly, and the Rct value decreased the most, indicating that discharging in the low potential region can significantly improve the charge transfer ability of the catalyst surface, thus enhancing the catalytic activity[\u003cspan additionalcitationids=\"CR43\" citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e lists the changes in the Rct values of the three Ni₂P catalysts after potentiostatic discharge. When the discharge potential decreased slowly, the Rct of the three catalysts decreased significantly. In particular, when a potentiostatic discharge of 0.05 V was used, LC-Ni₂P showed a very obvious decrease in Rct, as specifically shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003e, Figure 7, and Figure 8.\u003c/p\u003e\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eChanges in RCT Values of Three Ni₂P Catalysts after Potentiostatic Discharge\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDischarge potential\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eA -Ni\u003csub\u003e2\u003c/sub\u003eP Rct\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLC-Ni\u003csub\u003e2\u003c/sub\u003eP Rct\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHC-Ni\u003csub\u003e2\u003c/sub\u003eP Rct\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\u003e0.05V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.6Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.5Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.3Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.15V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25.3Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.8Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.4Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.25V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.1Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.2Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.7Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.35V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20.8Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.1Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.1Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.45V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18.6Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.6Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e09.5Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.55V\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.3Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e09.2Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e08.4Ω\u0026middot;cm\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3. The Influence of the Potentiostatic Discharge Process on the OER Performance of the Catalyst\u003c/h2\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.1. Effects of constant potential discharge time on OER activity\u003c/h2\u003e\n \u003cp\u003eThe potentiostatic discharge time has a significant impact on the activity of the Oxygen Evolution Reaction (OER) catalyst. During the potentiostatic discharge (0.05 V, 100 s) process, the morphology of the catalyst has changed remarkably. As can be observed from the SEM images (Fig. \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e), especially for the HC-Ni₂P electrode, the surface has transformed from a sheet-like structure into a rough surface layer formed by fine nanoparticles, indicating that prolonging the discharge time is conducive to the reconstruction of the surface structure[\u003cspan class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e46\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.2 Ionization Discharge Effects on Catalysts: Raman and EPR Analysis\u003c/h2\u003e\n \u003cp\u003eUsing Raman spectroscopy and EPR techniques, significant insights into the effects of ionization discharge on catalyst surface structures have been gained. In Raman spectra(Figure 10a), the peak at 1300 cm\u003csup\u003e-1\u003c/sup\u003e for A-Ni\u003csub\u003e2\u003c/sub\u003eP, LC-Ni\u003csub\u003e2\u003c/sub\u003eP, and HC-Ni\u003csub\u003e2\u003c/sub\u003eP is attributed to carbon paper. A new peak at 500 cm\u003csup\u003e-1\u003c/sup\u003e emerges during constant potential discharge experiments, resulting from Ni-O stretching vibrations at high potentials. This indicates the formation of nickel oxide on the catalyst surface[\u003cspan class=\"CitationRef\"\u003e47\u003c/span\u003e]. EPR spectra reveal the presence of unpaired electrons, with similar peak intensities and a consistent g-value of 2.002 across A-Ni\u003csub\u003e2\u003c/sub\u003eP, LC-Ni\u003csub\u003e2\u003c/sub\u003eP and HC-Ni\u003csub\u003e2\u003c/sub\u003eP, suggesting a commonality of oxygen vacancies. After constant potential discharge, the EPR spectra for the Ni\u003csub\u003e2\u003c/sub\u003eP types show increased peak intensities༈Figure 10c༉, particularly for LC-Ni\u003csub\u003e2\u003c/sub\u003eP at -0.05 V, indicating an accumulation of oxygen vacancies. This enhancement in oxygen vacancies correlates with improved catalyst performance, particularly in increasing OER activity[\u003cspan class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e49\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.3 XPS analysis of the constant discharge process\u003c/h2\u003e\n \u003cp\u003eXPS analysis shows (Fig. 10b-d、f-h) that the Ni-P bond in the Ni₂P spectrum disappears and the Ni-O bond is strengthened after the discharge, indicating that the degree of oxidation of the surface nickel increases during the discharge process. Eventually, nickel oxide rather than phosphide is mainly formed on the catalyst surface. In contrast, there are no significant changes in the surface morphology and crystal structure of the A-Ni₂P and LC-Ni₂P electrodes after potentiostatic discharge. This difference suggests that a longer potentiostatic discharge time can promote the xidation reaction on the catalyst surface, thereby improving the OER activity of the catalyst[\u003cspan class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e50\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e52\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4. Surface Reconstruction and Formation of Oxygen Vacancies\u003c/h2\u003e\n \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.1. Influence of the Discharge Process on the Formation of Oxygen Vacancies\u003c/h2\u003e\n \u003cp\u003eThe discharge process plays a crucial role in the formation of oxygen vacancies in the catalyst. Under the given potentiostatic discharge conditions, electrochemical rearrangement occurs on the catalyst surface, leading to the formation of more oxygen vacancies. As shown in Fig. \u003cspan class=\"InternalRef\"\u003e11\u003c/span\u003ea, the EPR analysis indicates that after potentiostatic discharge, the number of oxygen vacancies in the three Ni₂P catalysts increases slightly, and the peak intensity of the LC-Ni₂P catalyst shows an extremely obvious increase, suggesting that more oxygen vacancies are generated on its catalyst surface. The increase in oxygen vacancies can enhance the OER activity of the catalyst. This is because oxygen vacancies can optimize the electron transfer ability of the catalyst and drive the decomposition process of oxygen molecules, thus promoting the OER reaction. In addition, the finite element simulation results show that during the advancing stage of the discharge process, the greater the charge number of the electrode, the more oxygen vacancies are generated, which further illustrates the influence of the discharge process on the formation of oxygen vacancies.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.2. Charge Transfer and Capacitance Analysis\u003c/h2\u003e\n \u003cp\u003eCharge transfer and capacitance analysis play a crucial role in understanding the improvement of catalyst performance. Different catalysts have different capacitance values during the discharge process. The capacitance differences among A-Ni₂P, LC-Ni₂P, and HC-Ni₂P are closely related to their surface charge accumulation capabilities. Catalysts with larger capacitances can achieve charge accumulation more quickly, thereby accelerating the discharge. This process will affect the charge distribution on the catalyst surface and the generation of oxygen vacancies. The results of the CP curve indicate that catalysts with larger capacitances discharge faster in the low potential region, can more effectively generate oxygen vacancies, and drive the redox reaction. Therefore, the increase in capacitance can promote the improvement of the catalyst surface structure and enhance the activity of the catalyst in the OER reaction[\u003cspan class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e54\u003c/span\u003e].\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.3. Simulation of the Discharge Process in the High Potential Region\u003c/h2\u003e\n \u003cp\u003eSimulating the discharge process in the high potential region through the finite element method helps to conduct an in-depth study of the distribution of charges on the catalyst surface and the formation rules of oxygen vacancies during the discharge process. The simulation results show (as in Fig. \u003cspan class=\"InternalRef\"\u003e11\u003c/span\u003ec-e) that when the discharge proceeds, the oxygen vacancies formed in the catalyst gradually increase with the increase of the discharge time, and the content of oxygen vacancies in the longitudinal direction of the electrode gradually decreases. The greater the total charge number contained in the electrode, the faster the discharge rate during the discharge process, and the faster the electrode potential drops to the potential plateau, resulting in the generation of more oxygen vacancies. In addition, the simulation also indicates that the rapid discharge situation caused by a high charge number will not only generate more oxygen vacancies but also significantly exacerbate the difference in the concentration gradient of oxygen vacancies, thereby further enhancing the OER activity of the catalyst.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study systematically explored the surface reconstruction of Ni₂P catalysts with different crystallinities during the Oxygen Evolution Reaction (OER) and the underlying mechanism for the improvement of their catalytic performance. After potentiostatic discharge, the formation of oxides on the catalyst surface and the generation of oxygen vacancies significantly enhanced its electrochemical performance. Based on the above - mentioned multi - dimensional data analysis and research, it is shown that the discharge process in the low - potential region promotes the surface reconstruction of the catalyst. Notably, the low - crystallinity Ni₂P (LC - Ni₂P) catalyst exhibits more oxygen vacancies after discharge, thus enhancing its OER activity. In addition, capacitance and charge transfer analyses further reveal the relationship between the discharge characteristics of the catalyst at different potentials and its catalytic performance. The simulation results also show that a larger capacitance and rapid discharge can more effectively generate oxygen vacancies and enhance the OER activity of the catalyst. In future research, it is possible to further explore the surface reconstruction processes under different catalyst materials and electrochemical conditions. By optimizing the catalyst structure, the OER performance is expected to be further improved, providing theoretical support and practical references for the efficient catalysis of clean energy.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was funded by the (2024) College Students\u0026apos; Innovation and Entrepreneurship Training Program of Jining Normal University (Project No.: X (2024) 11427028) and the 2024 Ordos City Social Science Research Project (Project Number: 2024S381).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot relevant.\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors have given their consent for the publication of this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMandula Huhe, Zhenhuan Ma and Xiangfeng Meng contributed equally to this work.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMingyu Yu\u003c/strong\u003e: Involved in catalyst synthesis experiments and data collection. \u003cstrong\u003eMandula Huhe\u003c/strong\u003e (co - first author): Optimized catalyst synthesis, led electrochemical tests, and analyzed data. \u003cstrong\u003eZhenhuan Ma\u003c/strong\u003e (co - first author): Assisted in catalyst - related experiments and data recording. \u003cstrong\u003eXiangfeng Meng\u0026nbsp;\u003c/strong\u003e(co - first author): Contributed to research concept and data analysis guidance. \u003cstrong\u003eXu Kai:\u0026nbsp;\u003c/strong\u003eResponsible for the calibration and maintenance of experimental equipment to ensure the smooth progress of the experiment. \u003cstrong\u003eJiaxin Dong\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;Sibin Zhang\u003c/strong\u003e: Participated in research planning and aided in electrochemical data analysis.\u003cstrong\u003e\u0026nbsp;Jiao Liu\u0026nbsp;\u003c/strong\u003e(corresponding author): Took overall responsibility for the research project, carefully guided the experimental design, strictly supervised the experimental process, controlled the quality of paper writing, and utilized personal resources to provide strong support for the project progress.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe are grateful to the funding programs and all team members. The (2024) College Students\u0026apos; Innovation and Entrepreneurship Training Program of Jining Normal University and the 2024 Ordos City Social Science Research Project provided financial support. Thanks also go to all team members for their hard work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eYANG X, SONG Y, WANG G, WANG W. A comprehensive review on the development of sustainable energy strategy and implementation in China . IEEE transactions on Sustainable Energy,1(2): 57-65. (2010)\u003c/li\u003e\n\u003cli\u003eMAZLOOMI K, GOMES C. Hydrogen as an energy carrier: Prospects and challenges. Renewable and sustainable energy reviews,16(5): 3024-33. (2012)\u003c/li\u003e\n\u003cli\u003eHENKENSMEIER D, CHO W-C, JANNASCH P, STOJADINOVIC J, LI Q, AILI D, JENSEN J O. Separators and Membranes for Advanced Alkaline Water Electrolysis . Chemical Reviews,124(10): 6393-443. 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(2023)\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":"","lastPublishedDoi":"10.21203/rs.3.rs-6398975/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6398975/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNi₂P catalysts with different crystallinities in the oxygen evolution reaction (OER) and their effects on the catalytic performance were studied. The mechanism of enhancing the OER activity by the surface structure of the catalysts was explored, and Ni₂P catalysts with different crystallinities were synthesized via the hydrothermal method. The crystal layouts, morphological transformations, and electrochemical properties of the catalysts were analyzed by XRD, SEM, XPS, EIS, EPR, and electrochemical tests. The relationship between the formation of oxygen vacancies and the OER performance was investigated by simulating the reconstruction of the catalyst surface during potentiostatic discharge operation. The results show that Ni₂P catalysts with different crystallinities exhibit different surface reconstruction behaviors during the discharge process. In particular, more oxygen vacancies are derived on the surface of the LC-Ni₂P catalyst, which greatly improves the OER activity. In addition, the lower LSV overpotential significantly enhances the OER performance of the catalyst. The discharge process actively promotes the generation of oxygen vacancies and accelerates the charge transfer rate. The conclusions indicate that the surface reconstruction process and the formation of oxygen vacancies are the key factors for improving the OER performance of Ni₂P catalysts. Discharging in the low potential region can induce the formation of oxygen vacancies, thus enhancing the catalytic ability of the catalyst.\u003c/p\u003e","manuscriptTitle":"Research on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-07 14:52:14","doi":"10.21203/rs.3.rs-6398975/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":"3ce2696f-9a0b-4d0b-ba3f-d03be44e3d15","owner":[],"postedDate":"May 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-26T06:25:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-07 14:52:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6398975","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6398975","identity":"rs-6398975","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}