Tungsten-nickel oxygen evolution reaction catalyst as well as preparation method and application thereof

Abstract

The invention discloses a tungsten-nickel oxygen evolution reaction catalyst and a preparation method and application thereof.The catalyst comprises a carrier foamed nickel and W-Ni3S2 growing on the carrier in situ, Ni and W form short-range heteronuclear double adsorption sites, and the distance between Ni and W is # imgabs0 #. The preparation method comprises the following steps that a foamed nickel loaded Ni-MOF nanosheet is prepared, and then adding tungsten salt and a sulfur source, vulcanizing Ni, and replacing part of Ni with W to obtain the tungsten-nickel oxygen evolution reaction catalyst. According to the invention, part of Ni in Ni3S2 is replaced by W to form short-range heteronuclear double adsorption sites, so that the catalyst has excellent oxygen evolution activity and stability.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalysis technology, and in particular to a tungsten-nickel oxygen evolution reaction catalyst and a preparation method and application thereof. Background Art

[0002] The rapid consumption of fossil fuels has led to environmental pollution and energy shortages, and there is an urgent need to develop environmentally friendly and renewable new energy sources. Although solar and wind energy are mainstream renewable energy sources, their temporal and spatial discontinuities limit their widespread application. Hydrogen (H2), as a renewable energy source that is easy to store, clean, pollution-free and has high energy density, is considered to be one of the potential candidates for future low-carbon energy systems. Although the theoretical limit voltage of water decomposition is 1.23V, a higher voltage needs to be applied in actual operation to drive the reaction. During the electrolysis of water, oxygen evolution reaction (OER) occurs at the anode and hydrogen evolution reaction (HER) occurs at the cathode. The main challenge is that the activity and stability of OER catalysts are insufficient at industrial current densities. Although precious metal oxides such as IrO2 and RuO2 have good activity, their application prospects are limited due to limited storage, high price and poor stability. Therefore, designing and constructing efficient and low-cost OER electrocatalysts to improve OER kinetics, reduce overpotential and improve water electrolysis efficiency is crucial to achieve efficient and stable hydrogen production at industrial current densities.

[0003] 3d transition metals represented by nickel have been shown to have good catalytic activity for alkaline OER reactions. However, most of these catalysts improve their catalytic activity through a lattice oxidation pathway, which sacrifices the lattice oxygen of the material itself, thereby limiting its long-range stability. Summary of the invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a tungsten-nickel oxygen evolution reaction catalyst having excellent electrocatalytic activity, and due to the specific catalytic reaction path brought about by its special heteronuclear short-range dual active site structure, it exhibits excellent long-range stability; the second purpose of the present invention is to provide a method for preparing the tungsten-nickel oxygen evolution reaction catalyst; the third purpose of the present invention is to provide an application of the tungsten-nickel oxygen evolution reaction catalyst.

[0005] Technical solution: The tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises a carrier nickel foam and W-Ni3S2 grown in situ on the carrier. The Ni-MOF nanosheets supported by the nickel foam are first obtained by hydrothermal reaction, and then a tungsten source and a sulfur source are added to sulfide the Ni, and part of the Ni is replaced by W to form a short-range heteronuclear double adsorption site, wherein the distance between Ni and W is

[0006] The molar ratio of nickel in the nickel salt to tungsten in the tungsten salt is 5 to 20: 1. By introducing W atoms, part of Ni is replaced by W to form short-range heteronuclear double adsorption sites, which can enhance the adsorption of the reactive intermediate OH, is more conducive to the combination of active site Ni and OH, and promotes the dissociation of water.

[0007] Preferably, the thickness of the nickel foam is 0.5 to 2 mm. As a self-supporting material, it loads W-Ni3S2, which has a high specific surface area and a uniformly distributed pore structure, providing an optimized path for the rapid transmission of molecules. In addition, it has good electrical conductivity and high stability, providing favorable conditions for catalytic reactions. The apparent current of the electrode is affected by the nickel foam of different thicknesses. As the thickness increases, the apparent current of the electrode gradually increases. When the thickness reaches about 2 mm, it tends to be unified, but its intrinsic activity shows a trend of first increasing and then decreasing with the increase of thickness. The W-Ni3S2 loaded with 1 mm nickel foam has the best intrinsic activity.

[0008] The method for preparing the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0009] (1) Preparation of Ni-MOF nanosheets supported by nickel foam

[0010] Weigh nickel salt and terephthalic acid, dissolve them in a mixed solvent of N,N-dimethylformamide, water and ethanol, add nickel foam, and perform hydrothermal reaction in a reactor to obtain Ni-MOF nanosheets loaded with nickel foam as a carrier;

[0011] (2) Preparation of nickel foam-supported W-Ni3S2 catalyst

[0012] A sulfur source and a tungsten salt are weighed, dissolved in water, added with the Ni-MOF nanosheets prepared in step (1), and subjected to a hydrothermal reaction in a reactor. After the reaction is completed, the reaction is dried to obtain the tungsten-nickel oxygen evolution reaction catalyst.

[0013] Preferably, in step (1), the nickel foam further comprises a pretreatment, wherein the pretreatment method is: washing in acetone, ethanol and deionized water respectively, and then removing the surface oxide film in dilute acid. The dilute acid used for treating the nickel foam is dilute sulfuric acid, dilute hydrochloric acid or dilute nitric acid, with a concentration of 1 to 3 mol L -1 The processing time is 5 to 30 minutes.

[0014] In the hydrothermal reaction process of step (1), nickel is used as the metal central atom and terephthalic acid is used as the ligand to react and generate Ni-MOF.

[0015] Preferably, in step (1), the temperature of the hydrothermal reaction is 120-160° C., and the reaction time is 4-8 hours.

[0016] Preferably, in step (1), the nickel salt is nickel chloride hexahydrate.

[0017] Preferably, in step (1), the volume ratio of N,N-dimethylformamide, water and ethanol is 4:1:1.

[0018] In step (2), during the hydrothermal reaction, the Ni in the Ni-MOF is sulfided, and part of the Ni is replaced by W, ultimately generating W-Ni3S2.

[0019] Preferably, in step (2), the temperature of the hydrothermal reaction is 140-180° C., and the reaction time is 12-16 hours.

[0020] Preferably, in step (2), the sulfur source is thioacetamide; and the tungsten salt is sodium tungstate dihydrate.

[0021] Preferably, in step (2), the drying temperature is 60°C.

[0022] The tungsten-nickel oxygen evolution reaction catalyst of the present invention is used as an anode catalyst for electrocatalytic water decomposition.

[0023] Invention Mechanism: The catalyst designed in the present invention has a unique confined short-range structure, and the adjacent heteronuclear metals have a limited distance, so that the oxygen evolution reaction can be carried out through a dual-site adsorption-coupling pathway (OPM mechanism). This pathway can overcome the mutual constraints of activity and stability in traditional reactions, thereby achieving high activity and stability.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by first forming Ni-MOF and then partially replacing Ni with W to form short-range heteronuclear double adsorption sites, the catalyst has excellent oxygen evolution activity and stability; (2) the method is simple and fast to operate, which is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a synthetic schematic diagram of the present invention;

[0026] Figure 2 This is the SEM spectrum of the Ni-MOF nanosheets supported by nickel foam prepared in Example 1 of the present invention;

[0027] Figure 3 The SEM spectrum of the W-Ni3S2 oxygen evolution reaction catalyst prepared in Example 1 of the present invention;

[0028] Figure 4 HRTEM spectrum of the W-Ni3S2 oxygen evolution reaction catalyst prepared in Example 1 of the present invention;

[0029] Figure 5The lattice fringe spectrum corresponding to Ni3S2 in the W-Ni3S2 oxygen evolution reaction catalyst prepared in Example 1 of the present invention;

[0030] Figure 6 The XRD spectrum of the W-Ni3S2 oxygen evolution reaction catalyst prepared in Example 1 of the present invention;

[0031] Figure 7 This is the original crystal structure diagram of Ni3S2;

[0032] Figure 8 The OER curves of W-Ni3S2 prepared in Examples 1 to 3 of the present invention and Ni3S2 / NF prepared in Comparative Example 1 in 1M KOH solution are compared;

[0033] Fig. 9 The OER curves of W-Ni3S2 prepared in Example 1 of the present invention and commercial RuO2 in 1M KOH solution are compared;

[0034] Fig.10 The stability test curve of the W-Ni3S2 oxygen evolution reaction catalyst prepared in 1M KOH solution in the present invention;

[0035] Fig.11 Polarization curves comparing the complete water splitting of commercial Pt / C‖W-Ni3S2 (catalyst prepared in Example 1) and the complete water splitting of commercial Pt / C‖RuO2 in 1M KOH solution. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below in conjunction with embodiments.

[0037] Example 1

[0038] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0039] (1) Preparation of Ni-MOF nanosheets supported by nickel foam

[0040] Pretreatment of nickel foam: Take a piece of nickel foam with a thickness of 1 mm, wash it in acetone, ethanol and deionized water respectively, and then remove the surface oxide film in dilute acid. The dilute acid used to treat the nickel foam is dilute nitric acid with a concentration of 3 mol L -1 , the treatment time is 30 min (the pretreatment method of nickel foam is the same in the following embodiments).

[0041] Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid, dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 hours.

[0042] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0043] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0044] Example 2

[0045] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0046] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.189 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0047] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0048] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 20:1).

[0049] Example 3

[0050] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0051] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0052] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.02 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0053] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 5:1).

[0054] Example 4

[0055] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0056] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.149 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0057] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0058] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0059] Example 5

[0060] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0061] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 140°C for 4 h.

[0062] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0063] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0064] Example 6

[0065] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0066] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 160°C for 4 h.

[0067] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0068] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0069] Example 7

[0070] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0071] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 6 h.

[0072] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0073] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0074] Example 8

[0075] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0076] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 3 h.

[0077] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0078] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0079] Example 9

[0080] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0081] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0082] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.15 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 12 h.

[0083] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0084] Example 10

[0085] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0086] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0087] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 120°C for 12 h.

[0088] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0089] Embodiment 11

[0090] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0091] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0092] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 160°C for 12 h.

[0093] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0094] Example 12

[0095] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0096] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0097] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 10 h.

[0098] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0099] Embodiment 13

[0100] The preparation method of the tungsten-nickel oxygen evolution reaction catalyst of the present invention comprises the following steps:

[0101] (1) Preparation of Ni-MOF nanosheets supported on nickel foam: Weigh an appropriate amount of 0.149 g of nickel chloride hexahydrate and 0.189 g of terephthalic acid and dissolve them in a mixed solvent of 20 mL of N,N-dimethylformamide, 5 mL of deionized water and 5 mL of ethanol and stir them thoroughly. Add a piece of pretreated nickel foam and react in a reactor at 120°C for 4 h.

[0102] (2) Preparation of W-Ni3S2 oxygen evolution reaction catalyst: Weigh 0.1127 g of thioacetamide and 0.0165 g of sodium tungstate dihydrate, dissolve in 30 mL of deionized water and mix well, add the product obtained in (1), and react in a reactor at 140°C for 14 h.

[0103] (3) The product obtained in (2) was dried under vacuum at 60°C overnight to obtain the product W-Ni3S2 / NF (Ni:W molar ratio 12:1).

[0104] Comparative Example 1

[0105] On the basis of Example 1, without adding sodium tungstate dihydrate, Ni3S2 / NF catalyst was obtained.

[0106] Structural characterization

[0107] The Ni-MOF nanosheets and W-Ni3S2 oxygen evolution reaction catalyst supported by nickel foam prepared in Example 1 were physically characterized by SEM, HRTEM, XRD and other methods. The results are as follows: Figures 2 to 7 shown.

[0108] SEM( Figure 2 ) It can be observed that the prepared Ni-MOF is evenly distributed on the surface of nickel foam.

[0109] SEM( Figure 3 )It can be observed that the prepared Ni3S2 is evenly distributed on the surface of nickel foam.

[0110] like Figure 4 As shown in Figure 2, the samples were observed by high-power transmission electron microscopy. Figure 5 As shown, further magnification shows that the material surface has ordered lattice fringes with a crystal plane spacing of 0.24nm, corresponding to the (111) crystal plane of Ni3S2. No lattice fringes corresponding to W are observed, proving that W exists in an amorphous form.

[0111] Depend on Figure 6 It can be seen from the XRD spectrum that the diffraction peak of the material is completely consistent with the Ni3S2 standard card (JCPDS card, 44-1418), and no W peak is observed in the W-Ni3S2 material, which once again confirms that W exists in an amorphous form.

[0112] Depend on Figure 7 From the original crystal structure of Ni3S2, it can be seen that the metal spacing between Ni and Ni is The subsequent introduction of W atoms to replace part of Ni did not significantly change the crystal structure of Ni3S2, and the metal spacing between W and Ni was

[0113] Performance Characterization

[0114] (1) Catalyst oxygen evolution performance test

[0115] The oxygen evolution performance of the catalysts prepared in Examples 1 to 3 and Comparative Example 1 was tested. The testing method was as follows: the samples were subjected to an electrocatalytic oxygen evolution reaction (OER) performance test in a 1M KOH solution. The electrocatalytic oxygen evolution reaction was tested using a three-electrode test system equipped with an electrochemical workstation CHI760E from Shanghai Chenhua Instrument Co., Ltd. to evaluate its catalytic activity.

[0116] Figure 8 , Fig. 9It is the oxygen evolution (OER) curve of the catalyst. It can be seen from the figure that as the molar ratio of Ni and W increases in Examples 1 to 3, the catalytic performance shows a trend of first increasing and then decreasing; compared with the comparative example without the introduction of W, the performance of Examples 1 to 3 is significantly improved after the introduction of W. This also shows that the introduction of W can enhance the adsorption of the reactive intermediate OH by the catalyst as a whole, which is more conducive to the combination of Ni and OH at the active site. At the same time, it promotes the dissociation of water; the OER activity of the W-Ni3S2 / NF oxygen evolution reaction catalyst prepared in Example 1 in alkaline electrolyte is much better than that of commercial RuO2.

[0117] (2) Catalyst stability performance test

[0118] The stability of the catalyst prepared in Example 1 was tested by the following method: in 1M KOH solution, 10 mA cm -2 The electrocatalytic oxygen evolution reaction (OER) stability test was carried out on the samples at a current density of . The electrocatalytic oxygen evolution reaction was tested using a three-electrode test system and equipped with an electrochemical workstation CHI760E from Shanghai Chenhua Instrument Co., Ltd. to evaluate its stability.

[0119] Fig.10 This is the W-Ni3S2 oxygen evolution reaction catalyst IT test curve, which proves that the catalyst prepared in Example 1 has excellent long-range stability. This is mainly due to its special heteronuclear short-range dual active site structure, which makes its catalytic reaction path different from that of traditional OER catalysts, thus showing excellent long-range stability.

[0120] (3) Catalyst water splitting performance test

[0121] The full water splitting performance of the catalyst prepared in Example 1 and commercial RuO2 was tested. The testing method was as follows: an alkaline electrolytic cell was assembled with Pt / C as the cathode, and W-Ni3S2 / NF prepared in Example 1 and commercial RuO2 as the anode, respectively. The full water splitting performance was evaluated using the electrochemical workstation CHI760E of Shanghai Chenhua Instrument Co., Ltd.

[0122] Fig.11 The polarization curves of the complete water splitting composed of Pt / C‖W-Ni3S2 and the complete water splitting composed of Pt / C‖RuO2 in 1M KOH solution are compared. It is found that the former has better activity in the complete water splitting process, which also indicates that the catalyst still has excellent performance in the actual complete water splitting process.

Claims

1. A tungsten-nickel oxygen evolution reaction catalyst, characterized in that: The method comprises a carrier nickel foam and W-Ni3S2 grown in situ on the carrier. The nickel salt is firstly hydrothermally reacted to obtain a Ni-MOF nanosheet with nickel foam as the carrier, and then a tungsten salt and a sulfur source are added to sulfide the Ni, and part of the Ni is replaced by W to form a short-range heteronuclear double adsorption site, where the distance between Ni and W is 2. The tungsten-nickel oxygen evolution reaction catalyst according to claim 1, characterized in that: The molar ratio of nickel in the nickel salt to tungsten in the tungsten salt is 5 to 20:

1.

3. The tungsten-nickel oxygen evolution reaction catalyst according to claim 1, characterized in that: The thickness of the nickel foam is 0.5-2 mm.

4. A method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Preparation of Ni-MOF nanosheets supported by nickel foam Weigh nickel salt and terephthalic acid, dissolve them in a mixed solvent of N,N-dimethylformamide, water and ethanol, add nickel foam, and perform hydrothermal reaction in a reactor to obtain Ni-MOF nanosheets loaded with nickel foam as a carrier; (2) Preparation of nickel foam-supported W-Ni3S2 catalyst A sulfur source and a tungsten salt are weighed, dissolved in water, added with the Ni-MOF nanosheets prepared in step (1), and subjected to a hydrothermal reaction in a reactor. After the reaction is completed, the reaction is dried to obtain the tungsten-nickel oxygen evolution reaction catalyst.

5. The method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to claim 4, characterized in that: In step (1), the temperature of the hydrothermal reaction is 120-160° C., and the reaction time is 4-8 hours.

6. The method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to claim 4, characterized in that: In step (2), the temperature of the hydrothermal reaction is 140 to 180° C., and the reaction time is 12 to 16 hours.

7. The method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to claim 4, characterized in that: In step (1), the nickel foam further comprises a pretreatment, wherein the pretreatment method is: washing in acetone, ethanol and deionized water respectively, and then removing the surface oxide film in dilute acid.

8. The method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to claim 4, characterized in that: The sulfur source is thioacetamide.

9. The method for preparing a tungsten-nickel oxygen evolution reaction catalyst according to claim 4, characterized in that: The nickel salt is nickel chloride hexahydrate; the tungsten salt is sodium tungstate dihydrate.

10. Use of the tungsten-nickel oxygen evolution reaction catalyst according to any one of claims 1 to 3 as an anode catalyst for electrocatalytic water decomposition.

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