Method for ligand-regulated surface restructuring of oxygen evolution catalysts, catalysts and applications

Abstract

The application discloses a kind of ligand control oxygen evolution catalyst surface reconfiguration method and catalyst and application.The method involves ligand tuning surface reconstruction, can simultaneously incorporate doped cation and oxygen vacancy, to improve the catalytic activity of OER.By using nickel telluride, nickel oxide, nickel sulfide or nickel selenide as a pre-catalyst, based on the ligand-induced delayed doping effect using ammonia complex in alkaline electrolyte, a surface engineering heterojunction structure consisting of nickel-based pre-catalyst and (oxy) hydroxide is developed.The method of the application is simple in process, easy to operate, and can be popularized in industry;And the oxygen evolution catalyst prepared has the characteristics of rich active site and oxygen vacancy, large chemical active surface area, good stability, controllable, low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of an oxygen evolution catalyst, and the catalyst and application, in particular to a method for ligand-regulated surface reconstruction of an oxygen evolution catalyst, and the catalyst and application. BACKGROUND

[0002] The escalating energy demand and the pressing global warming issue force society to increasingly rely on renewable energy. Water electrolysis is considered as a promising approach to convert the electrical energy provided by renewable energy sources such as wind, solar and tidal energy into chemical energy through electrocatalytic processes, serving various applications in the future hydrogen economy. Developing efficient and durable cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) electrocatalysts is crucial to unleash the potential of water electrolysis. However, the actual water-splitting electrolyzer is facing the limitations of low operational efficiency and high cell voltage, mainly attributed to the anodic OER. OER (4OH - → O2 + 2H2O + 4e - , vs. RHE) involves a multi-step proton-coupled electron transfer process, whose slow reaction kinetics greatly hinders the overall efficiency of the reaction, emphasizing the necessity of addressing the challenge of developing effective OER catalysts for the widespread implementation of water electrolysis. According to the Sabatier principle, the binding strength of oxygen on the catalyst surface should not be too strong or too weak to achieve high-efficiency catalytic purposes.

[0003] Currently, the most advanced OER catalysts, such as noble metal-based materials such as Ir, Ru and their corresponding alloys and oxides, face major limitations in large-scale applications due to their scarcity, high cost and stability issues. In view of this fact, it is of great significance and urgency to develop efficient non-noble metal catalysts with high activity, low cost and abundant OER reserves.

[0004] To date, various transition metal (TM)-based materials, including metal alloys, hydroxides, oxides, sulfides, selenides, tellurides, borides, nitrides, carbides, phosphides, metal-organic frameworks and their derivatives, have been extensively studied for catalyzing OER in alkaline electrolytes, achieving significant progress. According to the degree of phase and structure change in the high oxidation potential range, OER catalysts can be divided into three types. The first type of catalyst remains stable without oxidation, showing inherent activity of OER catalysts in the original state even under alkaline oxidation conditions. The second type involves complete oxidation under OER conditions, resulting in transformation into low-crystalline or amorphous metal oxide / (oxy)hydroxide. In the third type, partial oxidation occurs, in which the catalyst surface is transformed into low-crystalline or amorphous oxide / (oxy)hydroxide, while the material core retains its unoxidized state, forming a core-shell catalyst.

[0005] Currently, transition metal (oxy)hydroxides are formed through irreversible structural transformation of the pre-catalyst and are widely accepted as the main catalytic species for OER, which are more thermodynamically stable than the pre-catalyst. The structural transformation can change the atomic arrangement and crystal structure of the catalyst surface, thereby changing the distribution of active sites and specific surface area. At the same time, it significantly affects the surface energy, adsorption and diffusion of reactants, and the stability of the catalyst. Some cationic species exhibit high instability during the OER process, which can leach from the lattice and cause significant structural changes in the pre-catalyst.

[0006] However, the leaching mechanism of metal impurities is often complex and has a complex relationship with composition, structure and defects, making the reconstruction mechanism complex and challenging. In addition, specific anions will be oxidized and dissolved during the OER process, leading to the oxidation of transition metal sites and the formation of metal oxides / (oxy)hydroxides. During the structural reconstruction process, the leaching of cationic or anionic species will lead to the formation of low-crystalline or amorphous phases with porous structures, increasing the specific surface area and exposing more loose-structure active sites, ultimately improving the OER catalytic performance.

[0007] However, the above reconstruction types require precise synthesis of pre-catalysts, a long activation period, and usually involve complex and elusive dissolution mechanisms, resulting in limited applicability of this strategy. In contrast, the introduction of impurity metals or anionic groups into the electrolyte during electrochemical activation can promote the adsorption of cationic doping or anionic groups on the surface structure, thereby enhancing the catalytic activity of metal sites. This strategy has significant adaptability and feasibility. However, the tendency of metal ions to combine and form precipitates often limits the metal doping content (ppm level), hindering the potential enhancement of catalytic activity. - The tendency of metal ions to combine and form precipitates often limits the metal doping content (ppm level), hindering the potential enhancement of catalytic activity.

[0008] Therefore, exploring a faster, more effective, and easier-to-scale electrolyte adjustment strategy is crucial for designing high-activity OER catalysts and deepening the understanding of OER catalytic mechanisms. SUMMARY

[0009] To solve the above technical problems, the present application provides a method for ligand-regulated surface reconstruction of oxygen evolution catalysts, a catalyst and an application. The method involves ligand-tuned surface reconstruction, which can simultaneously incorporate doped cations and oxygen vacancies to improve the catalytic activity of OER. By using nickel-based materials as pre-catalysts, based on the ligand-induced delayed doping effect using ligand sources in alkaline electrolyte, a surface-engineered heterojunction structure composed of nickel-based pre-catalysts and (oxy)hydroxides is developed. By comparing different ligands, such as neutral ligands (NH3, H2O), anionic ligands (NCS -1 , CN -1The study found that the performance of the pre-catalyst after surface reconstruction is related to the strength of the ligand coordination field and the charge of the ligands. During electrochemical activation, the delayed doping effect significantly promotes metal ion doping and oxygen vacancy generation. The method of this invention is simple, easy to operate, and industrially applicable; moreover, the prepared oxygen evolution catalyst has abundant active sites and oxygen vacancies, a large chemically active surface area, good stability, tunability, and low cost.

[0010] One of the technical solutions of the present invention:

[0011] A method for ligand-regulated surface reconstruction of an oxygen evolution catalyst is provided, comprising the following steps:

[0012] S1. Clean and dry the nickel foam, and set aside.

[0013] S2. Dissolve Na2TeO3 in water, then add hydrazine hydrate, stir well to obtain solution A;

[0014] S3. Place the nickel foam into the reactor, then transfer solution A into the reactor, heat to carry out the reaction, and allow it to cool naturally to room temperature after the reaction is complete;

[0015] S4. Remove the substrate from S3, rinse it sequentially with water and ethanol, and then dry it to obtain the pre-catalyst NiTe. x -original;

[0016] S5. Add ligand source, Fe(NO3)3·9H2O, Na2MoO4·2H2O and Cr(NO3)3·9H2O to KOH solution to obtain electrolyte;

[0017] S6. Take the NiTe obtained in S4 x The original catalyst was activated by cyclic voltammetry in the electrolyte obtained from S5, then washed sequentially with water and ethanol, and finally dried to obtain the ligand-regulated oxygen evolution catalyst, named: NiTe. x / FeCrMo-ligand.

[0018] Preferably, in the aforementioned method for ligand-regulated oxygen evolution catalyst surface reconstruction, the nickel foam in S1 is sequentially cleaned with acetone, ethanol, hydrochloric acid, and water.

[0019] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, in step S2, the molar concentration of Na2TeO3 in solution A is 30-50 mmol / L, and the volume ratio of hydrazine hydrate to water is 0.5-1.5:10.

[0020] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, the stirring time in S2 is 20-40 min.

[0021] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, the heating temperature in step S3 is 150-200°C, and the reaction time is 20-30 h.

[0022] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, the drying temperature described in S1, S4, and S6 is 50-70°C, and the drying time is 8-9 hours.

[0023] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, the concentration of the KOH solution in S5 is 0.8-1.2 mol / L, and the mass ratio of the ligand source, Fe(NO3)3·9H2O, Na2MoO4·2H2O and Cr(NO3)3·9H2O is 1:1-2:1-2:1-2.

[0024] Preferably, in the aforementioned method for ligand-regulated surface reconstruction of the oxygen evolution catalyst, the ligand source in S5 is one of NH4F, KSCN, or K3[Fe(CN)6], preferably NH4F.

[0025] Preferably, in the aforementioned method for ligand-regulated oxygen evolution catalyst surface reconstruction, the cyclic voltammetry described in S6 specifically uses NiTe x -Original is the working electrode, carbon rod is the counter electrode, and Hg / HgO is the reference electrode; the CV scan voltage range is -0.1-1.0V, the scan rate is 50mV / s, and the number of scans is 200.

[0026] Preferably, the aforementioned method for ligand-regulated oxygen evolution catalyst surface reconstruction can further incorporate the pre-catalyst NiTe in S6. x -Original can be replaced with one of NiO, NiS2 or NiSe2. When the precatalyst is replaced, the steps S1-S4 can be omitted.

[0027] The second technical solution of the present invention:

[0028] A ligand-regulated oxygen evolution catalyst is provided, which is prepared by the method described in Scheme 1.

[0029] The third technical solution of the present invention:

[0030] This invention provides an application of ligand-regulated oxygen evolution catalysts in the catalytic oxygen evolution reaction.

[0031] The beneficial effects of this invention are:

[0032] 1. The process of this invention is simple, easy to operate, and convenient for industrial promotion and implementation.

[0033] 2. The NiTe material prepared in this inventionx / FeCrMo- ligands have abundant active sites and oxygen vacancies.

[0034] After electrochemical CV activation, such as NiTe x / FeCrMo-NH4F forms a truly active MOOH phase on the material surface. NH4F provides ligand NH3, which forms a complex with the metal element Fe, avoiding the formation of metal hydroxide precipitation. The metal elements Fe and Cr in the electrolyte are doped into MOOH, while the doped metal element Mo, due to its large atomic radius, high valence state, and large migration barrier, does not enter the crystal lattice, but promotes the formation of oxygen vacancies in the catalyst, further enhancing the oxygen evolution reaction (OER) catalytic activity of the catalyst.

[0035] 3. The method of the present invention is simpler than the traditional method. By controlling the concentration and position of the dopant, the concentration distribution and position distribution of the dopant atoms can be adjusted, thereby achieving flexible control of the active sites of the catalyst.

[0036] Through doping and vacancy modulation, the reaction formation energy barriers of intermediates O* and OOH* were significantly optimized. x The FeCrMo-NH4F oxygen evolution catalyst, used as the anode in the electrolysis of alkaline water, exhibits excellent OER activity, requiring only low overpotentials of 208 mV and 239 mV to drive 10 mA cm⁻¹, respectively. -2 and 100mAcm -2 The current density has a Tafel slope of only 41.0 mVdec. -1 This indicates that it has a rapid catalytic rate and good reaction kinetics, with a Cdl value of 8.38 mFcm. -2 This indicates that it has the highest electrochemically active surface area. NiTe after ECSA normalization treatment... x / FeCrMo-NH4F still exhibits the best catalytic activity. The EIS plot shows that NiTe... x / FeCrMo-NH4F exhibits minimal charge transfer impedance and excellent long-term stability at a current density of 500 mA / cm². -2 Under these conditions, stability can reach 1000 hours.

[0037] 4. The NiTe of the present invention x / FeCrMo-NH4F catalyst is a non-precious metal composite material, and the raw materials used are easy to purchase, abundant in resources, and low in cost. Attached Figure Description

[0038] Figure 1 This is the NiTe of Embodiment 1 of the present invention. x XRD pattern of FeCrMo-NH4F material;

[0039] Figure 2 This is the NiTe of Embodiment 1 of the present invention. x SEM image of FeCrMo-NH4F material;

[0040] Figure 3 This is the NiTe of Embodiment 1 of the present invention. x TEM image of FeCrMo-NH4F material;

[0041] Figure 4 This is the NiTe of Embodiment 1 of the present invention. x HAADF-STEM image of FeCrMo-NH4F material;

[0042] Figure 5 This is the NiTe of Embodiment 1 of the present invention. x XPS O1s plot of FeCrMo-NH4F material;

[0043] Figure 6 This is the NiTe of Embodiment 1 of the present invention. x Schematic diagram of the synthesis of FeCrMo-NH4F material;

[0044] Figure 7 This is the NiTe of Embodiment 1 of the present invention. x The OER performance of / FeCrMo-NH4F material at 1 mol / L KOH includes linear sweep voltammetry curves at different rotation speeds with a scan rate of 2 mV / s, overpotential histograms at different current densities, Tafel slope, double-layer capacitance plot, ECSA-normalized linear sweep voltammetry curves, TOF curves, EIS plots, and stability tests.

[0045] Figure 8 This invention is NiTe x NiTe prepared from different ligand sources M x LSV plot of / FeCrMo-M catalyst; from Figure 8 It can be seen that NiTe x / FeCrMo-NH4F exhibits the best performance, but catalysts modified with other ligand sources and other metals all outperform NiTe. x . Detailed Implementation

[0046] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0047] Embodiments of the present invention

[0048] Example 1:

[0049] NiTe xThe preparation method of / FeCrMo-NH4F material includes the following steps:

[0050] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 60°C for 9 hours.

[0051] 2) Weigh 2 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 30 minutes, then add 5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 30 minutes.

[0052] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in an oven at 180°C for 24 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a vacuum drying oven at 60°C for 9 hours to obtain NiTe. x -original;

[0053] 4) Add 50 mg NH4F, 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte.

[0054] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1 to 1.0 V (vs. Hg / HgO), the scan rate was 50 mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60 °C for 9 h to obtain the ligand-regulated oxygen evolution catalyst, named NiTe. x / FeCrMo-NH4F.

[0055] In this example, NiTe x Taking FeCrMo-NH4F material as an example, its structure was determined by X-ray diffraction.

[0056] like Figure 1 As shown, the diffraction peak positions are respectively associated with the NiTe phase (JCPDS#01-089-7179) and Ni 10.35 Te 7.97 The diffraction peaks of the phase (JCPDS#00-019-0846) matched, confirming that NiTe xThe phase is a mixture of the two. The peaks at 30.9°, 42.7°, 45.7°, 56.2°, and 58.1° correspond to the (101), (102), (110), (201), and (103) planes of NiTe (JCPDS#01-089-7179), respectively. The peaks at 27.1°, 28.8°, 29.8°, 33.9°, 35.4°, 37.0°, 39.3°, 45.1°, and 46.3° correspond to the Ni 10.35 Te 7.97 The (111), (004), (022), (023), (121), (104), (114), (025), and (200) planes of (JCPDS#00-019-0846) were examined. Due to the low crystallinity of NiOOH, no NiOOH peaks were observed in the XRD. The Fe, Cr, and Mo content was very low in the reconstructed material structure, so no Fe, Cr, or Mo peaks were observed in the XRD.

[0057] NiTe x Scan of FeCrMo-NH4F ( Figure 2 The relatively rough nanosheet structure can be clearly seen.

[0058] Furthermore, through transmission electron microscopy (TEM) images ( Figure 3 This further confirms the nanosheet structure, and clear lattice fringes can be observed, with a lattice spacing of [missing information]. and Corresponding to Ni 10.35 Te 7.97 The (111) crystal plane of the NiTe phase and the (101) crystal plane of the NiTe phase have a lattice spacing of and The (111) and (011) crystal planes correspond to the NiOOH (JCPDS#27-956) phase.

[0059] HAADF-STEM( Figure 4 The data shows that the elements Ni, Te, Fe, Cr, and O are uniformly distributed in NiTe. x On the FeCrMo-NH4F nanosheets, successful doping with Fe and Cr was observed. Due to the large atomic radius, high valence state, and large migration barrier of Mo, it is difficult to enter the crystal lattice, so Mo was not observed.

[0060] XPS fine spectrum of O1s ( Figure 5 NiTe x / FeCrMo-NH4F has abundant oxygen vacancies.

[0061] NiTe in this examplex The electrocatalytic oxygen evolution performance of / FeCrMo-NH4F was measured using a Chenhua CHI660E workstation, with NiTe x The FeCrMo-NH4F electrode is used as the working electrode, Hg / HgO is used as the reference electrode, and a carbon rod is used as the counter electrode. A 1 mol / L KOH solution is injected into the electrolytic cell as the electrolyte to form a three-electrode testing system.

[0062] NiTe prepared in this example x Taking FeCrMo-NH4F as an example, its OER performance is as follows: Figure 7 As shown, the linear sweep voltammetry test results performed in 1 mol / L KOH solution at a scan rate of 2 mV / s indicate that only low overpotentials of 208 mV and 239 mV are required to drive a 10 mA cm⁻¹ solution. -2 and 100mAcm -2 The current density has a Tafel slope of only 41.0 mVdec. -1 This indicates that it has a rapid catalytic rate and good reaction kinetics, C dl It is 8.38mFcm -2 This indicates that it possesses the highest electrochemically active surface area. The calculated ECSA was used to normalize the LSV curve of the sample, thereby measuring the intrinsic activity of the material. After ECSA normalization, NiTe... x / FeCrMo-NH4F still exhibits the best catalytic activity. The EIS plot shows that NiTe... x / FeCrMo-NH4F exhibits the lowest charge transfer impedance, indicating superior electron transport and faster reaction kinetics. Stability was tested using a chronopotentiometric method at a current density of 500 mA / cm². -2 Under these conditions, the stability can reach 1000 hours, demonstrating exceptional stability.

[0063] Example 2:

[0064] NiTe x The preparation method of FeCrMo-KSCN material includes the following steps:

[0065] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 60°C for 9 hours.

[0066] 2) Weigh 2 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 30 minutes, then add 5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 30 minutes.

[0067] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in an oven at 180°C for 24 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a vacuum drying oven at 60°C for 9 hours to obtain NiTe. x -original;

[0068] 4) Add 50 mg KSCN, 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte.

[0069] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the ligand-regulated oxygen evolution catalyst, named NiTe. x / FeCrMo-KSCN.

[0070] NiTe prepared in this example x Taking FeCrMo-KSCN material as an example, the linear scanning voltammetry test results conducted in 1 mol / L KOH solution at a scan rate of 2 mV / s show that at a current density of 10 mA / cm²... 2 and 100mA / cm 2 The overpotentials are 218mV and 250mV, respectively.

[0071] Example 3:

[0072] NiTe x The preparation method of / FeCrMo-K3[Fe(CN)6] material includes the following steps:

[0073] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 60°C for 9 hours.

[0074] 2) Weigh 2 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 30 minutes, then add 5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 30 minutes.

[0075] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in an oven at 180°C for 24 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a vacuum drying oven at 60°C for 9 hours to obtain NiTe. x -original;

[0076] 4) Add 50 mg K3[Fe(CN)6], 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte.

[0077] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the ligand-regulated oxygen evolution catalyst, named NiTe. x / FeCrMo-K3[Fe(CN)6].

[0078] NiTe prepared in this example x Taking FeCrMo-K3[Fe(CN)6] material as an example, the linear scanning voltammetry test results conducted in 1 mol / L KOH solution at a scan rate of 2 mV / s show that at a current density of 10 mA / cm²... 2 and 100mA / cm 2 The overpotentials are 222mV and 258mV, respectively.

[0079] Example 4:

[0080] NiTe x The preparation method of / FeCrMo-NH4F material includes the following steps:

[0081] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 50°C for 9 hours.

[0082] 2) Weigh 1.5 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 20 minutes, then add 2.5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 20 minutes.

[0083] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in a 150 °C oven for 30 h. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, place it in a 50 °C vacuum drying oven for 9 h to obtain NiTe. x -original;

[0084] 4) Add 50 mg NH4F, 50 mg Fe(NO3)3·9H2O, 50 mg Na2MoO4·2H2O and 50 mg Cr(NO3)3·9H2O to 0.8 mol / L KOH solution to obtain a clear red electrolyte;

[0085] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the ligand-regulated oxygen evolution catalyst, named NiTe. x / FeCrMo-NH4F.

[0086] Example 5:

[0087] NiTe x The preparation method of / FeCrMo-NH4F material includes the following steps:

[0088] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 70°C for 8 hours.

[0089] 2) Weigh 2.5 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 40 minutes, then add 7.5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 40 minutes.

[0090] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in a 200°C oven for 20 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a 70°C vacuum drying oven for 8 hours to obtain NiTe. x -original;

[0091] 4) Add 50 mg NH4F, 100 mg Fe(NO3)3·9H2O, 100 mg Na2MoO4·2H2O and 100 mg Cr(NO3)3·9H2O to a 1.2 mol / L KOH solution to obtain a clear red electrolyte.

[0092] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the ligand-regulated oxygen evolution catalyst, named NiTe. x / FeCrMo-NH4F.

[0093] Example 6:

[0094] NiTe x The preparation method of FeCrMo material includes the following steps:

[0095] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 60°C for 9 hours.

[0096] 2) Weigh 2 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 30 minutes, then add 5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 30 minutes.

[0097] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in an oven at 180°C for 24 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a vacuum drying oven at 60°C for 9 hours to obtain NiTe. x -original;

[0098] 4) Add 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain an electrolyte with a red precipitate.

[0099] 5) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 4), using NiTe xThe original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the oxygen evolution catalyst, named NiTe. x / FeCrMo.

[0100] NiTe prepared in this example x Taking FeCrMo material as an example, the linear scanning voltammetry test results performed in 1 mol / L KOH solution at a scan rate of 2 mV / s show that at a current density of 10 mA / cm², 2 and 100mA / cm 2 The overpotentials are 240mV and 298mV, respectively.

[0101] Example 7:

[0102] NiTe x The preparation method of the material includes the following steps:

[0103] 1) Before use, the nickel foam should be cleaned with acetone, ethanol, hydrochloric acid and deionized water in sequence, and then dried in a vacuum drying oven at 60°C for 9 hours.

[0104] 2) Weigh 2 mmol Na2TeO3 and dissolve it in 50 mL of deionized water. Stir for 30 minutes, then add 5 mL of hydrazine hydrate dropwise to the solution and continue stirring for 30 minutes.

[0105] 3) Transfer the above mixed solution to a 100 mL polytetrafluoroethylene (PTFE) reactor liner. Place a pre-treated piece of nickel foam in the reactor liner beforehand. React in an oven at 180°C for 24 hours. After cooling to room temperature, remove the nickel foam and rinse three times with deionized water and ethanol, respectively. Then, dry it in a vacuum drying oven at 60°C for 9 hours to obtain NiTe. x -original;

[0106] 4) Take the NiTe obtained in step 3) x The original sample was activated by cyclic voltammetry (CV) in a 1 mol / L KOH electrolyte, with NiTe x The original electrode was used as the working electrode, the carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scan voltage range was -0.1-1.0V (vs. Hg / HgO), the scan rate was 50mV / s, and the number of scan cycles was 200. The catalyst was then rinsed with deionized water and ethanol, and dried in a vacuum oven at 60℃ for 9 hours to obtain the oxygen evolution catalyst, named NiTe. x .

[0107] NiTe prepared in this example x Taking the material as an example, the linear sweep voltammetry test results performed in 1 mol / L KOH solution at a scan rate of 2 mV / s show that at a current density of 10 mA / cm², 2 and 100mA / cm 2 The overpotentials are 387mV and 470mV, respectively.

[0108] Example 8:

[0109] The preparation method of NiO / FeCrMo-NH4F material includes the following steps:

[0110] 1) Add 50 mg NH4F, 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte;

[0111] 2) NiO was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 1). NiO was used as the working electrode, carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scanning voltage range was -0.1 to 1.0 V (vs. Hg / HgO), the scanning rate was 50 mV / s, and the number of scans was 200. Then, it was rinsed with deionized water and ethanol, and dried in a vacuum drying oven at 60 °C for 9 h to obtain the ligand-controlled oxygen evolution catalyst, named: NiO / FeCrMo-NH4F.

[0112] Example 9:

[0113] The preparation method of NiS2 / FeCrMo-NH4F material includes the following steps:

[0114] 1) Add 50 mg NH4F, 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte;

[0115] 2) NiS2 was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 1). NiS2 was used as the working electrode, carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scanning voltage range was -0.1 to 1.0 V (vs. Hg / HgO), the scanning rate was 50 mV / s, and the number of scans was 200. Then, it was rinsed with deionized water and ethanol, and dried in a vacuum drying oven at 60 °C for 9 h to obtain the ligand-controlled oxygen evolution catalyst, named: NiS2 / FeCrMo-NH4F.

[0116] Example 10:

[0117] The preparation method of NiSe2 / FeCrMo-NH4F material includes the following steps:

[0118] 1) Add 50 mg NH4F, 75 mg Fe(NO3)3·9H2O, 75 mg Na2MoO4·2H2O and 75 mg Cr(NO3)3·9H2O to a 1 mol / L KOH solution to obtain a clear red electrolyte;

[0119] 2) NiSe2 was activated by cyclic voltammetry (CV) in the electrolyte prepared in step 1). NiSe2 was used as the working electrode, carbon rod as the counter electrode, and Hg / HgO as the reference electrode. The CV scanning voltage range was -0.1 to 1.0 V (vs. Hg / HgO), the scanning rate was 50 mV / s, and the number of scans was 200. Then, it was rinsed with deionized water and ethanol, and dried in a vacuum drying oven at 60 °C for 9 h to obtain the ligand-controlled oxygen evolution catalyst, named: NiSe2 / FeCrMo-NH4F.

[0120] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of ligand-mediated surface restructuring of an oxygen evolution catalyst, characterized in that, The method comprises the following steps: S1. The foam nickel is sequentially cleaned with acetone, ethanol, hydrochloric acid and water and dried for standby; S2. Na2TeO3 is dissolved in water, then hydrazine hydrate is added and stirred uniformly to obtain A liquid; S3. The foam nickel is placed in a reaction kettle, then the A liquid is transferred into the reaction kettle and heated for reaction, and after the reaction is completed, it is naturally cooled to room temperature; S4. The foam nickel of S3 is taken out, sequentially washed with water and ethanol, and then dried to obtain a pre-catalyst NiTex-original; S5. A ligand source, Fe(NO3)3·9H2O, Na2MoO4·2H2O and Cr(NO3)3·9H2O are added into a KOH solution to obtain an electrolyte; S6. The pre-catalyst NiTex-original obtained in S4 is placed in the electrolyte obtained in S5 for cyclic voltammetry activation, then sequentially washed with water and ethanol, and finally dried to obtain a ligand-regulated oxygen evolution catalyst. The ligand source in S5 is one of NH4F, KSCN or K3[Fe(CN)6].

2. The method for ligand-regulated surface reconstruction of oxygen evolution catalyst according to claim 1, characterized in that: In S2, the molar concentration of Na2TeO3 in the A liquid is 30-50 mmol / L, the volume ratio of hydrazine hydrate to water is 0.5-1.5:10, and the stirring time is 20-40 min.

3. The method for ligand-regulated surface reconstruction of oxygen evolution catalyst according to claim 1, characterized in that: In S3, the heating temperature is 150-200℃, and the reaction time is 20-30 h.

4. The method for ligand-regulated surface reconstruction of oxygen evolution catalyst according to claim 1, characterized in that: In S1, S4 and S6, the drying temperature is 50-70℃, and the time is 8-9 h.

5. The method for ligand-regulated surface reconstruction of oxygen evolution catalyst according to claim 1, characterized in that: In S5, the concentration of the KOH solution is 0.8-1.2 mol / L, and the mass ratio of the ligand source, Fe(NO3)3·9H2O, Na2MoO4·2H2O and Cr(NO3)3·9H2O is 1:1-2:1-2:1-2.

6. The method for ligand-regulated surface reconstruction of an oxygen evolution catalyst according to claim 1, characterized in that: In S6, the cyclic voltammetry is specifically that the NiTex-original is used as a working electrode, a carbon rod is used as a counter electrode, and Hg / HgO is used as a reference electrode; the CV scanning voltage range is-0.1-1.0 V, the scanning rate is 50 mV / s, and the scanning number is 200.

7. A ligand-regulated oxygen evolution catalyst prepared by the method according to any one of claims 1-6.

8. Application of the ligand-regulated oxygen evolution catalyst according to claim 7 in catalyzing an oxygen evolution reaction.

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