CN115679339A

CN115679339A - Sulfur-doped phosphide polymorph heterojunction complete-decomposition hydroelectric catalyst and preparation method thereof

Info

Publication number: CN115679339A
Application number: CN202110832633.9A
Authority: CN
Inventors: 章福祥; 兰希德; 范文俊
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2021-07-22
Filing date: 2021-07-22
Publication date: 2023-02-03

Abstract

The invention provides a sulfur-doped phosphide polymorph heterojunction complete decomposition hydroelectric catalyst and a preparation method thereof. The chemical formula of the catalyst is S-M _x P _y /M _a P _b Wherein S represents sulfur element, M represents any one of Fe, co, ni, mo, mn and Cu, and P represents phosphorus element, and the fully decomposed hydro-electric catalyst is prepared by assembling the fully decomposed hydro-electric catalyst on a conductive carrier by a solvothermal-phosphorization-sulfur doping method. The phosphide polymorphous heterojunction is prepared by regulating the phosphating temperature and atmosphere, and the obtained catalyst has a two-dimensional nanosheet structure, high specific surface area and good conductivity; the best catalyst is in alkaline electrolyteIn 500mA cm ^‑2 The activity is stable for more than 1000 hours under high current density without significant change. Meanwhile, the catalyst has excellent full water decomposition performance of 500mA cm ^‑2 The overpotential of the fully decomposed water at high current density is only 460mV. The preparation method provides a feasible scheme for preparing the efficient and cheap phosphide full-decomposition water electro-catalysis material.

Description

Sulfur-doped phosphide polymorph heterojunction complete-decomposition hydroelectric catalyst and preparation method thereof

Technical Field

The invention belongs to the field of catalytic materials, and particularly relates to a sulfur-doped phosphide polymorphic heterojunction catalyst, a preparation method thereof and application thereof in electrocatalytic water decomposition hydrogen and oxygen evolution.

Background

Hydrogen energy is being widely developed and applied to the fields of hydrogen-oxygen fuel cells and the like as an ideal ultimate energy source, wherein the technology of utilizing electric energy generated by renewable energy sources to electrolyze water to produce hydrogen is a necessary way for realizing green hydrogen energy economy and is also the development direction of hydrogen fuel cells in the future. The key point of storing and converting renewable energy into hydrogen energy is to reduce the cost of hydrogen production, namely to improve the efficiency and stability of hydrogen production, and the core of the method lies in the development of efficient hydrogen and oxygen evolution catalysts. At present, compared with the acid electrolyzed water, the alkaline electrolyzed water has the advantages of more mature technology, wider use, low cost, simple process, convenient operation, high purity of the produced hydrogen (up to 99-99.99 percent) and the like. However, at present, the hydrogen evolution catalyst with the most excellent performance is still platinum group noble metal, the oxygen evolution catalyst depends on iridium oxide and ruthenium oxide, platinum, iridium and ruthenium are all noble metals, the reserves on the earth are small, and the popularization and the application of the catalyst on the industry are not facilitated, so that the development of non-noble metal catalysts with abundant earth contents is imperative.

Heretofore, researchers found that transition metal carbides, nitrides, sulfides and the like have bifunctional catalytic activity on hydrogen evolution and oxygen evolution, but the currently reported hydrogen evolution and oxygen evolution catalysts show high activity in acidic and alkaline media respectively, and how to prepare a bifunctional transition metal catalyst with high activity and high stability in an alkaline environment is still a difficult problem to be solved urgently in the field of water electrocatalytic decomposition. Transition metal phosphide M _x P _y (CoP、Ni ₂ P、Cu ₃ P, moP, etc.) are interstitial compounds formed by P atoms entering transition metal lattices, and have high chemical stability, high catalytic activity and good performanceThe reaction kinetics of (A) are widely applied to the fields of hydrodesulfurization, electrocatalytic water decomposition and the like. Transition metal phosphides exhibit relatively high electrocatalytic hydrogen evolution properties, but have relatively low electrocatalytic oxygen evolution properties, limiting their application as bifunctional catalysts. The difunctional phosphide catalyst for alkaline all-water electrolysis reported at present needs 1.6V of voltage to reach 10mA cm ^-2 The current density of (a), the efficiency of catalytic electrolysis of water, cannot meet the requirements of commercialization.

Scholars at home and abroad improve the performance of the catalyst in decomposing water completely through strategies of heteroatom doping, defect construction, composite structure construction and the like, for example, daniel et al reports that the electronic structure of phosphide is changed by using Fe doping, and the efficiency and the stability of the catalyst are improved (Proceedings of the National Academy of Sciences,2017,114 (7): 1486-1491). Qian et al reported that the CoP/FeNi-LDH complex structure promotes OH ^- The adsorption of (1) can be activated to greatly reduce the overpotential compared with that of a single catalyst (Angewandte Chemie International Edition,2019,58 (34): 11903-11909.). For phosphides, the ratio of M and P determines the properties of the material. When x is more than or equal to 1, the material has higher conductivity, but the capability of activating water molecules is weaker. When x is y<1, especially x: y<2, the electron-rich property of P can effectively adsorb protons and promote the activation of water molecules, but the reduction of the content of M-M bonds greatly inhibits the conductivity of the material. So far, the research of applying the heterostructure constructed by the polymorph of phosphide to fully decompose water is not reported, and key scientific and technical problems such as the structure-activity relationship of catalyst synthesis and electrocatalysis performance, structure optimization design and the like are urgently needed to be solved.

Disclosure of Invention

The invention aims to provide a sulfur-doped phosphide polymorphic heterojunction catalyst with high activity and high stability for electrocatalytic total decomposition of water. The catalyst prepared by the invention is loaded on a conductive substrate, has a two-dimensional ultrathin structure, a large specific surface area and high conductivity, can greatly reduce overpotential and Tafel slope of hydrogen evolution and oxygen evolution at 500mA cm ^-2 Can maintain the performance for 1000h without attenuation under current density, and has obviously improved activity compared with a single-component phosphide catalystSex and stability. Therefore, the sulfur-doped phosphide polymorphous heterojunction catalyst has good application prospect when being applied to fully decomposed water.

The technical scheme of the invention is as follows:

in one aspect, the invention provides a sulfur-doped phosphide polymorph heterojunction fully decomposed hydroelectric catalyst, wherein the catalyst is a heterostructure of sulfur-doped polymorph phosphide, and the catalyst has the chemical formula S-M _x P _y /M _a P _b Wherein S represents sulfur element, M represents any one of Fe, co, ni, mo and Mn, and P represents phosphorus element; the value ranges of x, y, a and b are as follows: x is more than or equal to 1 and less than or equal to 12, y is more than or equal to 1 and less than or equal to 5, a is more than or equal to 1 and less than or equal to 12, b is more than or equal to 1 and less than or equal to 5; the content of S in the catalyst is 0.2at.% to 10at.%; the catalyst is in a two-dimensional nanosheet shape.

Based on the above scheme, preferably, the value ranges of x, y, a, and b are: x is more than or equal to 1 and less than or equal to 4, y is more than or equal to 1 and less than or equal to 4, a is more than or equal to 1 and less than or equal to 2, b is more than or equal to 1 and less than or equal to 4; the amount of S in the catalyst is 1at.%4at.%; in the heterostructure M _x P _y And M _a P _b The ratio of (1); the M is Co; the thickness of the nano-sheet is 1-10nm, and the size of the nano-sheet is 50-5000nm.

Based on the above scheme, preferably, M in the heterostructure _x P _y And M _a P _b The ratio of (1); the thickness of the nano sheet is 1-10nm; further preferably 4nm, and the size of the nano-sheet is 200-2000nm; more preferably 1000nm.

In another aspect, the present invention provides a method for preparing the above catalyst, wherein the catalyst is prepared by a solvothermal-phosphorization-sulfur doping method and assembled on a conductive carrier, and the method specifically comprises the following steps:

(1) Taking metal salt of M as a precursor, and performing solvothermal synthesis on two-dimensional MO in a mixed solution of P123, ethanol, water, hexamethylenetetramine and ethylene glycol _x Nanosheets;

(2) MO synthesized by the step (1) _x The nano sheet is used as a precursor, mixed with a phosphorus source and then subjected to in-situ phosphorization to obtain MO _x Topologically converted to phosphide heterojunction nanosheets;

(3) And (3) taking the phosphide heterojunction nanosheet synthesized in the step (2) as a precursor, adding a sulfur source and a conductive carrier, and synthesizing the supported phosphide heterojunction catalyst by a solvothermal method.

Based on the scheme, preferably, in the step (1), the solvothermal synthesis reaction is carried out in a hydrothermal kettle, the hydrothermal temperature is 100-250 ℃, and the hydrothermal reaction time is 0.5-24h; the metal salt of M is one of acetate, nitrate, chloride and acetylacetone compound of M; the mass ratio of the P123 to the ethanol to the water to the ethylene glycol to the metal salt to the hexamethylenetetramine is 1; the mixing mode of the raw materials in the step (1) is as follows: adding P123 into ethanol, then adding water, and uniformly stirring to obtain a solution 1; and then adding the metal salt precursor into the solution 1 for M, uniformly stirring, adding hexamethylenetetramine, subsequently adding ethylene glycol, and uniformly stirring to obtain the mixed solution.

Based on the scheme, in the step (1), the hydrothermal temperature is preferably 100-190; further preferably 170 ℃, and the hydrothermal reaction time is 1-10h; further preferably 2h; the metal salt of M is acetate; the mass ratio of the P123, ethanol, water, glycol, metal salt and hexamethylenetetramine is 1.

Based on the scheme, preferably, in the step (2), the phosphorus source is sodium hypophosphite, the in-situ phosphorization is carried out in a tubular furnace, the air pressure in the tubular furnace is 0.1-1MPa, and the atmosphere in the tubular furnace is N ₂ The gas flow is 10-200sccm, and the temperature of the tubular furnace is 200-900 ℃; in the step (3), the sulfur source is thioacetamide, thiourea or mercaptan; the solvent for the solvothermal synthesis is C1-5 alcohol; the mass ratio of the solvent to the sulfur source is (100); the temperature of solvothermal synthesis is 80-200 ℃, and the time is 0.5-48 h; the conductive carrier is one of foamed nickel, nickel mesh, raney nickel, foamed copper, foamed iron, foamed cobalt, carbon cloth and carbon paper.

Based on the above scheme, preferably, in the step (2), the gas pressure in the tube furnace is 0.2 to 0.5MPa, more preferably 0.1MPa, the gas flow rate is 10 to 100sccm, more preferably 50sccm, and the temperature of the tube furnace is 100 to 500 ℃, more preferably 350 ℃; in the step (3), the sulfur source is thioacetamide, and the solvent for solvothermal synthesis is ethanol; the mass ratio of the solvent to the sulfur source is 200 to 500, and more preferably 500; the temperature of the solvothermal synthesis is 100-190 ℃, the further optimization is 120 ℃, and the time is 1-10h, the further optimization is 6h; the conductive carrier is a nickel net.

As a further preferred of the above scheme, the present invention provides a preparation method of the sulfur-doped phosphide polymorph heterojunction total decomposition water catalyst, which comprises the following specific steps:

a: adding 50-500mg of P123 into 5-50mL of ethanol, then adding 0.5-5mL of water, and uniformly stirring to obtain a solution 1;

b: adding 0.177-1.77g of metal salt precursor into the solution 1, uniformly stirring, adding 5-50mg of hexamethylenetetramine, then adding 10-20mL of glycol, and uniformly stirring to obtain a solution 2;

c: putting the solution 2 into a 25-250mL hydrothermal kettle, reacting for 1-10h at 100-200 ℃, and washing to obtain two-dimensional MO _x ；

D: the obtained two-dimensional MO _x Mixing with 50-500mg sodium hypophosphite, and phosphorizing at 200-600 deg.C for 2-10h in N baking atmosphere ₂ Preparing the two-dimensional phosphide polymorphic heterojunction catalyst;

e: dispersing 10-100mg of prepared two-dimensional phosphide polymorphic heterojunction catalyst in 5-50mL of ethanol, adding 30-300mg of S-containing precursor, fully stirring, reacting the mixed solution in a 25-250mL hydrothermal kettle at 100-200 ℃ for 2-24h, washing with ethanol and secondary water respectively after the reaction is finished, and drying to obtain the catalyst.

In another aspect, the invention provides an application of the catalyst in electrocatalytic water decomposition for hydrogen and oxygen evolution. The specific reaction conditions are as follows: and D, directly taking the conductive carrier loaded catalyst obtained in the step E as a hydrogen evolution electrode and an oxygen evolution electrode, and carrying out electrocatalytic full-water decomposition reaction by using a two-electrode system.

Based on the above scheme, preferably, the electrolyte used for the electrocatalytic water decomposition reaction is an alkaline electrolyte, and the alkali is one of KOH, naOH, liOH, and CsOH, preferably KOH; the concentration of the alkaline electrolyte is 0.5-10M, preferably 1M.

Advantageous effects

The invention discloses a simple and low-cost method for synthesizing M with a polymorphic heterojunction structure _x P _y /M _a P _b A catalytic material. As a non-noble metal bifunctional catalyst, the invention has the following advantages:

(1) The sulfur-doped phosphide catalytic material prepared by the invention has a polymorphic heterostructure, the polymorphic heterostructure of phosphide is prepared by adjusting the phosphating temperature and atmosphere, the relative proportion of the heterostructure can be adjusted and controlled between 1 and 10, the synthesis method is simple, the production mode is flexible, and the relative proportion can be adjusted and controlled according to different requirements;

(2) The sulfur-doped phosphide polymorph heterostructure provided by the invention has a two-dimensional structure, a high specific surface area, high conductivity, excellent hydrogen evolution and oxygen evolution activity and stability, and can be used for electrically and catalytically evolving hydrogen 50mA cm under an alkaline condition ^-2 ，500mA cm ^-2 The overpotential under the current density is only 50mV and 150mV, and the electrocatalytic oxygen evolution is 50mA cm ^-2 And 500mA cm ^-2 The overpotential under the current density is only 240mV and 340mV at 500mA cm ^-2 The activity is stable for more than 1000 hours under high current density without significant change. Meanwhile, the catalyst has excellent water full-decomposition performance at 500mA cm ^-2 The overpotential of the fully decomposed water at high current density is only 490mV.

Drawings

FIG. 1 is a drawing of the S-CoP/Co prepared in example 1 ₂ P-polymorphic-heterojunction (a) low power and (B) high power transmission diagrams.

FIG. 2 is the S-CoP/Co prepared in example 1 ₂ Linear scans of (a) electrocatalytic hydrogen evolution and (B) electrocatalytic oxygen evolution in 1M KOH for P-polymorphic heterojunction electrodes.

FIG. 3 is the S-CoP/Co prepared in example 1 ₂ Linear scans of P polymorphic heterojunction electrodes fully decomposed water in 1M KOH.

FIG. 4 shows an embodiment1 preparation of S-CoP/Co ₂ P polymorphous heterojunction electrodes 500mA cm in 1M KOH ^-2 At current density>An electrocatalytic oxygen evolution stability diagram of 1000 h.

FIG. 5 is the S-NiP/Ni prepared in example 2 ₂ Linear scans of P polymorphic heterojunction electrodes fully decomposed water in 1M KOH.

Detailed Description

To further illustrate the present invention, the following examples are given in conjunction with the accompanying drawings and are not intended to limit the scope of the invention as defined in the claims. The starting materials used in the examples are all conventional commercially available starting materials unless otherwise specified.

Example 1

Adding 20mg P123, 0.5g cobalt acetate and 10mg hexamethylenetetramine into 20mL ethanol, 1mL water and 10mL glycol solution, and uniformly stirring; transferring the solution into a reaction kettle to react for 5 hours at the temperature of 150 ℃, washing and drying to obtain the two-dimensional CoO _x (ii) a The obtained two-dimensional CoO _x Mixing with 200mg sodium hypophosphite, phosphorizing at 300 deg.C for 5 hr in roasting atmosphere N ₂ Preparing the two-dimensional phosphide polymorphic heterojunction catalyst; dispersing 50mg of prepared two-dimensional cobalt phosphide polymorphic heterojunction catalyst in 20mL of ethanol containing 50% thioacetamide precursor, fully stirring, adding 1cm × 1cm of foamed nickel, then reacting the mixed solution in a 50mL hydrothermal kettle at 120 ℃ for 10h, washing with ethanol and secondary water respectively after the reaction is finished, and drying to obtain the catalyst S-CoP/Co loaded on the foamed nickel ₂ P。

The results of the electrocatalytic total moisture decomposition reaction using the conductive carrier-supported catalyst prepared in example 1 as a hydrogen evolution electrode and an oxygen evolution electrode directly in a two-electrode system using 1M KOH as an electrolyte are shown in fig. 2 to 4. Electrocatalytic hydrogen evolution 50mA cm under alkaline condition ^-2 ，500mA cm ^-2 The overpotential under the current density is only 50mV and 150mV, and the electrocatalytic oxygen evolution is 50mA cm ^-2 And 500mA cm ^-2 Overpotential at current density of 240mV and 340mV at 500mA cm ^-2 The activity is stable for more than 1000 hours under high current density without significant change. Meanwhile, the catalyst has excellent water fully-decomposing performance,at 500mA cm ^-2 The overpotential of the fully decomposed water at high current density is only 490mV.

Example 2

Adding 40mg P123, 0.5g nickel acetate and 20mg hexamethylenetetramine into 20mL ethanol, 2mL water and 20mL glycol solution, and uniformly stirring; transferring the solution into a reaction kettle to react for 5 hours at the temperature of 150 ℃, washing and drying to obtain two-dimensional NiO _x (ii) a The obtained two-dimensional NiO _x Mixing the two-dimensional phosphide and 400mg of sodium hypophosphite, and phosphorizing for 5 hours at 300 ℃ to prepare a two-dimensional phosphide polymorphic heterojunction catalyst; dispersing 100mg of prepared two-dimensional nickel phosphide polymorphic heterojunction catalyst in 40mL of ethanol containing thioacetamide precursor, fully stirring, putting the mixture into a 1cm by 1cm nickel net, and then reacting the mixed solution in a hydrothermal kettle at 120 ℃ for 10 hours to obtain the catalyst S-NiP/Ni loaded on foamed nickel ₂ P。

The obtained catalyst is subjected to electrocatalytic hydrogen evolution 50mA cm in 1M KOH electrolyte under the alkaline condition ^-2 ，500mA cm ^-2 The overpotential under the current density is only 70mV and 170mV, and the electrocatalytic oxygen evolution is 50mA cm ^-2 And 500mA cm ^-2 The overpotential under the current density is only 260mV and 360mV at 500mA cm ^-2 The activity of the oxygen evolution under high current density is stable for more than 500 hours without significant change. Meanwhile, the catalyst has excellent water fully-decomposing performance at 500mA cm ^-2 The overpotential of the fully decomposed water at high current density is only 530mV.

Example 3

Adding 30mg of P123, 0.5g of ferric acetylacetonate and 20mg of hexamethylenetetramine into 20mL of ethanol, 2mL of water and 30mL of glycol solution, and uniformly stirring; transferring the solution into a hydrothermal kettle to react for 5 hours at the temperature of 150 ℃, washing and drying to obtain two-dimensional FeO _x (ii) a The obtained two-dimensional FeO _x Mixing with 400mg sodium hypophosphite, phosphorizing at 300 deg.C for 5 hr in roasting atmosphere N ₂ Preparing the two-dimensional phosphide polymorphic heterojunction catalyst; dispersing 100mg of prepared two-dimensional iron phosphide polymorphic heterojunction catalyst in 40mL of ethanol containing thiourea precursor, fully stirring, putting the mixture into a 1cm by 1cm nickel net, and then reacting the mixed solution in a 50mL hydrothermal kettle at 130 ℃ for 10h to obtain the catalyst S-FeP/Fe loaded on the nickel net ₂ P。

The obtained catalyst is subjected to electrocatalytic hydrogen evolution with 50mA cm of hydrogen under the alkaline condition in 1M KOH electrolyte ^-2 ，500mA cm ^-2 The overpotential under the current density is only 70mV and 170mV, and the electrocatalytic oxygen evolution is 50mA cm ^-2 And 500mA cm ^-2 The overpotential at current density is only 250mV and 350mV at 500mA cm ^-2 The activity of the oxygen evolution under high current density is stable for more than 600 hours without significant change. Meanwhile, the catalyst has excellent water fully-decomposing performance at 500mA cm ^-2 The overpotential of the fully decomposed water at high current density is only 520mV.

Example 4

Adding 50mg of P123, 0.5g of cobalt acetylacetonate and 20mg of hexamethylenetetramine into 30mL of ethanol, 5mL of water and 20mL of glycol solution, and uniformly stirring; transferring the solution into a reaction kettle to react for 10 hours at 180 ℃, and washing and drying to obtain CoO _x (ii) a The obtained CoO _x Mixing with 600mg of sodium hypophosphite, and then phosphorizing for 3h at 300 ℃, wherein the roasting atmosphere is Ar, and preparing the phosphide polymorphic heterojunction catalyst; dispersing 100mg of prepared cobalt phosphide polymorphic heterojunction catalyst in 60mL of ethanol containing thiourea precursor, fully stirring, putting the mixture into a 1cm x 2cm nickel net, and then reacting the mixed solution in a 50mL hydrothermal kettle at 130 ℃ for 10h to obtain the catalyst S-CoP loaded on the nickel net ₂ /Co ₂ P。

The obtained catalyst is subjected to electrocatalytic hydrogen evolution 50mA cm in 1M KOH electrolyte under the alkaline condition ^-2 ，500mA cm ^-2 The overpotential under the current density is only 80mV and 180mV, and the electrocatalytic oxygen evolution is 50mA cm ^-2 And 500mA cm ^-2 The overpotential under the current density is only 260mV and 360mV at 500mA cm ^-2 The activity of the oxygen evolution under high current density is stable for more than 700 hours without significant change. Meanwhile, the catalyst has excellent water fully-decomposing performance at 500mA cm ^-2 The overpotential of the fully decomposed water at high current density is only 540mV.

The present invention is illustrated in detail by the examples described above, but the present invention is not limited to the details described above, i.e., it is not intended that the present invention be implemented by relying on the details described above. It is obvious to those skilled in the art that any modification of the present invention, equivalent substitution of each raw material and addition of auxiliary components, selection of specific modes and the like of the product of the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A sulfur-doped phosphide polymorph heterojunction complete-decomposition hydroelectric catalyst is characterized in that: the catalyst is a heterostructure of sulfur-doped polymorph phosphide, and the chemical formula of the catalyst is S-M _x P _y /M _a P _b Wherein S represents sulfur element, M represents any one of Fe, co, ni, mo, mn and Cu, and P represents phosphorus element; the value ranges of x, y, a and b are as follows: x is more than or equal to 1 and less than or equal to 12, y is more than or equal to 1 and less than or equal to 5, a is more than or equal to 1 and less than or equal to 12, b is more than or equal to 1 and less than or equal to 5; the amount of S in the catalyst is 0.2at.%10at.%; the catalyst is in a two-dimensional nanosheet shape.

2. The catalyst of claim 1, wherein: the value ranges of x, y, a and b are as follows: x is more than or equal to 1 and less than or equal to 4, y is more than or equal to 1 and less than or equal to 4, a is more than or equal to 1 and less than or equal to 2, b is more than or equal to 1 and less than or equal to 4; the amount of S in the catalyst is 1at.%4at.%; in the heterostructure M _x P _y And M _a P _b The ratio of (1); the M is Co; the thickness of the nano sheet is 1-10nm, and the size of the nano sheet is 50-5000nm.

3. The catalyst of claim 2, wherein: in the heterostructure M _x P _y And M _a P _b The ratio of (1); the thickness of the nano-sheet is 1-10nm, and the size of the nano-sheet is 200-2000nm.

4. A method for preparing the catalyst according to any one of claims 1 to 3, wherein the catalyst is prepared by a solvothermal-phosphorization-sulfur doping method and assembled on a conductive carrier, and the method comprises the following steps:

(2) To be provided withMO synthesized in step (1) _x The nano sheet is used as a precursor, mixed with a phosphorus source and then subjected to in-situ phosphorization to obtain MO _x Topologically transforming into phosphide heterojunction nanosheets;

5. The method according to claim 4, wherein in the step (1), the solvothermal synthesis reaction is carried out in a hydrothermal kettle, the hydrothermal temperature is 100-250 ℃, and the hydrothermal reaction time is 0.5-24h; the metal salt of M is one of acetate, nitrate, chloride and acetylacetone compound of M; the mass ratio of the P123 to the ethanol to the water to the ethylene glycol to the metal salt to the hexamethylenetetramine is 1;

the mixing mode of the raw materials in the step (1) is as follows: adding P123 into ethanol, then adding water, and uniformly stirring to obtain a solution 1; and then adding the metal salt precursor into the solution 1 for M, uniformly stirring, adding hexamethylenetetramine, subsequently adding ethylene glycol, and uniformly stirring to obtain the mixed solution.

6. The method according to claim 5, wherein in the step (1), the hydrothermal temperature is 100-190 ℃, and the hydrothermal reaction time is 1-10h; the metal salt of M is acetate; the mass ratio of the P123, ethanol, water, ethylene glycol, metal salt and hexamethylenetetramine is 1.

7. The method according to claim 4, wherein in step (2), the phosphorus source is sodium hypophosphite, and the in-situ phosphating is carried out in a tube furnace having an air pressure of 0.1-1MPa and an atmosphere of N ₂ The gas flow is 10-200sccm, and the temperature of the tubular furnace is 200-900 ℃; in the step (3), the sulfur source is thioacetamide, thiourea or mercaptan; the solvent for solvothermal synthesis is C1-C5 alcohol; the mass ratio of the solvent to the sulfur source is100; the temperature of the solvothermal synthesis is 80-200 ℃, and the time is 0.5-48 h; the conductive carrier is one of foam nickel, a nickel net, raney nickel, foam copper, foam iron, foam cobalt, carbon cloth and carbon paper.

8. The method according to claim 7, wherein in the step (2), the gas pressure in the tube furnace is 0.2 to 0.5MPa, the gas flow rate is 10 to 100sccm, and the temperature of the tube furnace is 100 to 500 ℃; in the step (3), the sulfur source is thioacetamide, and the solvent for solvothermal synthesis is ethanol; the mass ratio of the solvent to the sulfur source is 200 to 500; the temperature of solvothermal synthesis is 100-190 ℃, and the time is 1-10h; the conductive carrier is a nickel net.

9. Use of a catalyst according to any one of claims 1 to 3 for the electrocatalytic decomposition of water into hydrogen and oxygen.

10. Use according to claim 9, characterized in that: the electrolyte used in the electrocatalytic water decomposition reaction is alkaline electrolyte, and the alkali is one of KOH, naOH, liOH and CsOH, preferably KOH; the concentration of the alkaline electrolyte is 0.5-10M, preferably 1M.