Hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalysts, preparation and applications thereof

Abstract

The application belongs to the field of electrocatalytic materials, and particularly relates to a hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: pre-treating mixed raw materials containing a molten salt, a carbon source, a transition metal source, a phosphorus source and an additive at a temperature T1 for a first-stage heat preservation, then heating to a temperature T2 and performing a second-stage heat preservation to obtain a precursor material; and performing rapid cooling treatment on the precursor material to obtain the hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst. The additive is a compound containing two or more acidic groups, and the acidic groups include at least one of a carboxylic acid group and a phosphoric acid group. The temperature T1 is 200-450 DEG C, and the temperature T2 is 850-1200 DEG C. The material has excellent acid and alkali resistance, HER and OER performance.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials, specifically relating to the field of water electrolysis catalyst materials. Background Technology

[0002] Water electrolysis, an electrochemical process that uses electricity to split water into hydrogen (H2) and oxygen (O2), is considered an effective way to achieve renewable energy storage and utilization. This process involves two main electrochemical reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). However, both reactions require highly efficient electrocatalysts to reduce the overpotential, improve energy conversion efficiency and reaction rate, thereby achieving more economical and efficient hydrogen production. Traditional electrocatalysts, such as noble metals (e.g., platinum, iridium), exhibit excellent catalytic performance, but their high cost and rarity limit their large-scale application. Noble metal catalysts are not only expensive but also have limited global reserves, failing to meet the needs of future large-scale industrial applications. Therefore, developing efficient, low-cost, and stable electrocatalysts has become a current research focus.

[0003] Against this backdrop, transition metal-based catalysts, especially transition metal phosphides (such as cobalt phosphides, nickel phosphides, and iron phosphides), have attracted widespread attention due to their low cost, abundant reserves, and excellent electrocatalytic performance.

[0004] Existing technologies also provide some solutions in this area. For example, Chinese patent document CN115458753A discloses a method for preparing a composite bifunctional electrocatalyst and its application in high-power zinc-air batteries. This catalyst is a composite material consisting of a nickel-iron hydrotalcite precursor obtained by chemical bath deposition, which is then annealed and phosphated to form a Ni2P / Fe2P heterophosphide and anion-doped hollow carbon spheres. This composite catalyst can achieve good OER performance.

[0005] For example, Chinese patent document CN116078412A discloses a heterogeneous composite material, which includes phosphated graphene as a support and cobalt-iron phosphide loaded on the support. The phosphated graphene is in a foam-like state, and the cobalt-iron phosphide is in a cubic particle-like state, forming a heterogeneous structure between the phosphated graphene and the cobalt-iron phosphide. This material exhibits excellent catalytic effects in both electrochemical hydrogen evolution and / or oxygen evolution reactions, and can be used for the selective oxidation of 5-hydroxymethylfurfural to furanyl dicarboxylic acid.

[0006] In addition, Chinese patent document CN113772644A discloses a bimetallic phosphide, its preparation method and application. The preparation method of the bimetallic phosphide includes the following steps: co-precipitating potassium ferricyanide and cobalt salt to prepare iron-cobalt Prussian blue; and then phosphating the iron-cobalt Prussian blue under a protective atmosphere to prepare a bimetallic phosphide.

[0007] In summary, existing technologies disclose some carbon-based non-silicon metal phosphide electrocatalytic materials, but these materials are difficult to balance acid and alkali resistance, as well as the effects of HER and OER, making them unsuitable for full hydrolysis applications and exhibiting poor stability. Summary of the Invention

[0008] In view of the shortcomings of existing carbon-based metal phosphide water electrolysis catalysts, the primary objective of this invention is to provide a method for preparing a hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst, aiming to prepare a novel material that can withstand acids and alkalis, while also exhibiting excellent OER and HER performance, and is suitable for full water electrolysis applications.

[0009] The second objective of this invention is to provide a hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst prepared by the aforementioned method.

[0010] The third objective of this invention is to provide an application of the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst for water electrolysis.

[0011] The fourth objective of this invention is to provide a water electrolysis device containing the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst for water electrolysis.

[0012] A method for preparing a hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst involves preheating a mixed raw material comprising molten salt, carbon source, transition metal source, phosphorus source, and additives at a temperature T1 for a first stage of heating, followed by heating to a temperature T2 and a second stage of heating to obtain a precursor material; the precursor material is then subjected to rapid cooling to obtain the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst.

[0013] The auxiliary agent is a compound containing two or more acidic groups; the acidic groups include at least one of carboxylic acid groups and phosphate groups;

[0014] Temperature T1 is 200–450℃; temperature T2 is 850–1200℃.

[0015] This invention innovatively employs a two-stage gradient treatment of transition metal, phosphorus, and carbon sources with the aid of molten salt and additives, further combined with subsequent rapid quenching. This allows for the in-situ formation of a hierarchical porous carbon substrate, upon which the crystalline-amorphous dual-phase metal phosphide material can be grown simultaneously in situ. Studies have shown that the material prepared by the method described in this invention exhibits excellent acid and alkali resistance, while also possessing excellent and stable HER and OER properties, making it suitable for applications involving complete hydrolysis.

[0016] In this invention, the molten salt includes at least one of sodium chloride, potassium chloride, potassium nitrate, sodium carbonate, ammonium nitrate, calcium fluoride, magnesium fluoride, and aluminum fluoride; preferably two or more; further, it can be a composite molten salt of sodium chloride and potassium nitrate (the weight ratio of the components in the composite molten salt can be 0.1 to 10:1). Studies have shown that using the aforementioned combined molten salt helps to further synergistically enhance the synergy of the two-stage gradient heat preservation-rapid cooling process described in this invention, helps to further optimize the crystal and amorphous behavior and composite interface of the prepared material, and helps to further improve its HER and OER performance.

[0017] In this invention, the carbon source includes at least one of inorganic carbon and organic carbon sources. The organic carbon source includes at least one of monosaccharide compounds, disaccharide compounds, polysaccharides, and polymers. The inorganic carbon includes, for example, at least one of graphitic carbon nitride and graphene oxide. The monosaccharide includes, for example, glucose. The disaccharide includes, for example, sucrose. The polymer includes, for example, at least one of starch and lignin. The polymer includes, for example, PVP.

[0018] Preferably, the carbon source comprises polysaccharides and polymers (the ratio of the two can be 1 to 5:1). Research in this invention shows that the preferred carbon source, combined with the molten salt-two-stage gradient calcination-quenching combined process described in this invention, can further achieve synergy, helping to further optimize the physicochemical structure of the prepared material and further enhance its HER and OER properties.

[0019] In this invention, the transition metal element in the transition metal source can be any transition metal element known in the industry that can be used for electrocatalysis. Preferably, the transition metal source contains two or more transition metal elements. Considering the effect and cost, it can include two or more of iron, nickel, and cobalt.

[0020] In this invention, the phosphorus source can be any component capable of providing phosphorus (P). Considering material costs, it can be at least one of dicalcium phosphate, potassium dihydrogen phosphate, superphosphate, and ammonium phosphate.

[0021] In this invention, the auxiliary agent includes at least one of phytic acid, oxalic acid, and citric acid.

[0022] In this invention, the weight ratio of the transition metal source (based on transition metal element), molten salt, carbon source and additive is 1:2-5:5-15:0.5-3, and may further be 1:2.5-4.5:5-10:1-2; wherein, the molar ratio of transition metal element / P element in the transition metal source and phosphorus source is 1:0.2-2 (and may further be 1:1-1.5).

[0023] In this invention, the mixed raw materials are obtained by solvent removal after liquid-phase mixing of molten salt, carbon source, transition metal source, phosphorus source, and additives. The solvent removal method is spraying.

[0024] In this invention, the processing atmosphere for the first and second stages of heat preservation is a protective atmosphere, which can further be a hydrogen-containing atmosphere. The hydrogen-containing atmosphere is, for example, a mixture of hydrogen and an inert gas, wherein the hydrogen content is, for example, 1–10 vol%.

[0025] In this invention, the temperature of the first insulation stage is 250–350°C.

[0026] Preferably, the insulation time for the first stage is 1 to 5 hours, and more preferably 2 to 3 hours.

[0027] In this invention, the temperature of the second insulation stage is 900–1050°C.

[0028] Preferably, the insulation time for the second stage is 1 to 5 hours, and more preferably 2 to 3 hours.

[0029] The cooling medium used in the quenching stage is a liquid medium with a temperature below 30°C; preferably water or liquid nitrogen. This invention demonstrates that using liquid nitrogen as the quenching medium, in combination with other components and processes, can achieve superior process synergy, further enhancing the acid and alkali resistance, HER, and OER properties of the prepared materials.

[0030] In this invention, during the rapid cooling stage, the temperature difference between the precursor material and the rapid cooling medium when they come into contact is above 500°C, and can further be 850–1200°C.

[0031] In this invention, the second insulation material can be placed in the quenching medium while it is still hot, so that the material is in direct contact with the quenching medium and undergoes quenching treatment.

[0032] This invention further includes a step of carbon coating the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst. The carbon coating step can be conventional; for example, the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst can be combined with a carbon source and then subjected to carbonization treatment.

[0033] The present invention also provides a hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst prepared by the above preparation method.

[0034] In this invention, the preparation method imparts unique physicochemical properties to the prepared material. For example, it can simultaneously construct a hierarchical porous carbon substrate and grow crystalline-amorphous composite technical phosphides in situ on the substrate. The material prepared by this invention has advantages such as acid and alkali resistance and excellent HER and OER performance.

[0035] The present invention also provides an application of the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst prepared by the above preparation method, which is used as a catalytic material for the electrocatalysis of water.

[0036] In this invention, the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst described in this invention can be used as a catalyst, and water electrocatalysis can be performed based on conventional water electrolysis methods and principles.

[0037] The present invention also provides a hydrocatalytic device comprising a hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst prepared by the preparation method, or prepared by the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst.

[0038] The hydrocatalytic device of the present invention, apart from containing the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst of the present invention, may have other known components and structural parts.

[0039] Beneficial effects:

[0040] This invention innovatively incorporates a transition metal source, a phosphorus source, and a carbon source into a two-stage gradient treatment with the assistance of molten salt and additives, further combined with a subsequent rapid quenching treatment. This allows for the in-situ formation of a catalytic material with the aforementioned physicochemical characteristics. Furthermore, the catalytic material exhibits excellent resistance to acids and alkalis, while also demonstrating superior HER and OER performance. It is suitable for applications involving complete hydrolysis and its stability is improved.

[0041] For example, the material described in this invention can reduce its HER potential to 69mV, OER potential to 1.455V, and total hydrolysis potential to 1.545V in an alkaline system. Compared with other carbon-based metal phosphide materials, it has excellent HER and OER performance. In addition, it can also obtain excellent HER and OER performance in an acidic system. Attached Figure Description

[0042] Figure 1 This is a graph showing the alkaline water decomposition stability of the material prepared in Example 1;

[0043] Figure 2 This is a graph showing the acidic water decomposition stability of the material prepared in Example 1;

[0044] Figure 3 This is a SEM image of the material prepared in Example 1. Detailed Implementation

[0045] The present invention discloses a method for preparing a crystalline-amorphous dual-phase metal phosphide electrocatalyst, the steps of which include: thoroughly mixing and dispersing a mixture of molten salt, carbon source, metal source, and phosphorus source in an additive solution S, and spray drying the mixture; then subjecting the mixture to two-stage calcination; rapidly cooling the material in cold water or liquid nitrogen while it is still hot; and finally washing it with water to obtain the water electrolysis material.

[0046] The molten salt contains at least one of sodium chloride, potassium chloride, potassium nitrate, sodium carbonate, ammonium nitrate, calcium fluoride, magnesium fluoride, and aluminum fluoride.

[0047] The carbon source includes at least one of graphitic carbon nitride, graphene oxide, glucose, sucrose, starch and lignin, preferably a mixture of the above carbon source and PVP.

[0048] The metal source includes one or more nitrates of iron, nickel, and cobalt, preferably a mixture of the above nitrates and potassium cobalt cyanide.

[0049] The phosphorus source comprises at least one of dicalcium phosphate, potassium dihydrogen phosphate, superphosphate, and ammonium phosphate.

[0050] The auxiliary agent solution S is a solution containing one or more of phytic acid, oxalic acid, citric acid, etc., with a concentration of 0.05-0.5M.

[0051] The gradient calcination process includes a first calcination process at temperature T1 and a second calcination process at temperature T2; wherein, temperature T1 is 200-450℃; and temperature T2 is 850-1200℃.

[0052] The following is a more detailed implementation method:

[0053] The weight of the transition metal source is measured by the weight of the transition metal elements contained therein.

[0054] Example 1

[0055] Step (1): Premixing

[0056] A mixture of transition metal source (a mixture of ferric nitrate, nickel nitrate, and potassium cobalt cyanide with a Fe / Ni / Co mass ratio of 0.5:0.2:1), molten salt (sodium chloride and potassium nitrate with a Na / K mass ratio of 1:0.5), carbon source (a mixture of lignin and PVP with a mass ratio of 1.5:0.5), and phosphorus source (calcium phosphate and potassium dihydrogen phosphate with a mass ratio of 1:0.3; the molar ratio of the metal element in the metal source to P in the phosphorus source is 1:1) was ground for 10 min. Then, a solution S containing an auxiliary agent (a mixed solution of 0.05M phytic acid and 0.2M oxalic acid) (the mass ratio of the auxiliary agent to the metal source is 1:2) was added, and the mixture was stirred for 10 min. Finally, the mixture was spray-dried to obtain mixture X.

[0057] Step (2): Gradient roasting - rapid cooling and quenching

[0058] The mixture X obtained in step (1) was placed in a tube furnace and 5v% H2 / Ar inert atmosphere was introduced to fill the tube with inert atmosphere until saturation. The temperature was increased to 250℃ (marked as T1) at a heating rate of 5℃ / min and held for 2h (marked as t1). Then the temperature was increased to 950℃ (sintering temperature T2) at a heating rate of 5℃ / min and held for 3h (marked as t2). Then the mixture was poured into liquid nitrogen while hot for rapid cooling to obtain component F.

[0059] Step (3): Wash with water

[0060] The component F obtained in step (2) was mixed with water at a mass ratio of 1:100, stirred vigorously for 10 minutes, filtered, and repeated three times to obtain the water electrolysis catalyst material (active material, also labeled as HPC-CAMP).

[0061] Example 2

[0062] Compared to Example 1, the only difference is that the type of molten salt was changed, and the experimental groups were as follows:

[0063] Group A: The molten salt is sodium chloride;

[0064] Group B: Molten salt is potassium nitrate;

[0065] The total weight of the molten salt and other operating conditions were the same as in Example 1, and the tests were conducted in the same manner as in Example 1. The results are shown in Table 1.

[0066] Example 3

[0067] Compared to Example 1, the only difference is that the type of carbon source was changed; the experimental groups were as follows:

[0068] Group A: The carbon source is glucose;

[0069] Group B: The carbon source is lignin;

[0070] Group C: Carbon source is PVP;

[0071] The total weight of the carbon source and other operating conditions were the same as in Example 1, and the tests were conducted in the same manner as in Example 1. The results are shown in Table 1.

[0072] Example 4

[0073] Compared to Example 1, the only difference is that the type of metal source is changed; the experimental groups are as follows:

[0074] Group A: The metal source is a mixture of ferric nitrate and potassium cobalt cyanide, with the same iron-cobalt ratio and total metal element weight as in Example 1;

[0075] Group B: The metal source is a mixture of nickel nitrate and potassium cobalt cyanide, with the same nickel-cobalt ratio and total metal element weight as in Example 1;

[0076] The weight of the metal source and other operating conditions were the same as in Example 1, and the tests were conducted in the manner described in Example 1. The results are shown in Table 1.

[0077] Example 5

[0078] Compared to Example 1, the only difference is that the type of solution S is changed, and the experimental groups are as follows:

[0079] Group A: Solution S is a 0.25M phytic acid solution;

[0080] Group B: Solution S is a 0.25M oxalic acid solution;

[0081] The total weight of the additives and other operating conditions were the same as in Example 1, and the tests were conducted in the manner described in Example 1. The results are shown in Table 1.

[0082] Example 6

[0083] Compared with Example 1, the only difference is that in step 2, the medium for rapid cooling is deionized water at 25°C, while other operations and parameters are the same as in Example 1.

[0084] Example 7

[0085] Compared with Example 1, the only difference is that in step 1, the weight ratio of the transition metal source, molten salt, and carbon source is 1:4:10; the molar ratio of the metal element in the metal source to P in the phosphorus source is 1:1.5; and the mass ratio of the additive to the metal source is 1:1. In step 2, the atmosphere is a 3v% H2 / Ar inert atmosphere, the temperature T1 is 350℃, and the holding time is 3h; the temperature T2 is 1000℃, and the holding time is 2h; after cooling to 850℃ in the furnace, rapid cooling is performed while still hot. All other operations and parameters are the same as in Example 1.

[0086] Comparative Example 1

[0087] Compared with Example 1, the only difference is that no molten salt was added in step (1), while the other operations and parameters are the same as in Example 1.

[0088] Comparative Example 2

[0089] Compared with Example 1, the only difference is that in step (1), solution S is water, and no auxiliary solute is added. All other operations and parameters are the same as in Example 1.

[0090] Comparative Example 3

[0091] Compared with Example 1, the only difference is that step (2) was not performed, and the two-stage gradient calcination process was not carried out. That is, the temperature of T1 was set to be the same as that of T2, and the other operations and parameters were the same as those in Example 1.

[0092] Comparative Example 4

[0093] Compared with Example 1, the only difference is that in step (2), rapid quenching was not performed. Instead, natural cooling was performed at room temperature after calcination. All other operations and parameters are the same as in Example 1.

[0094] Electrochemical performance testing of materials:

[0095] Using a rotating disk electrode, with the HPC-CAMP as the working electrode, a mercury oxide (alkaline) or saturated calomel electrode (acidic) as the reference electrode, and a platinum electrode as the counter electrode, the catalytic performance was tested in a three-electrode system.

[0096] Catalytic performance testing under alkaline conditions: In a 1M KOH system, the HER reaction was performed at a current density of 10 mA cm⁻¹. -2 Overpotential (η) j＝10 The voltage was 69.4 mV; the OER reaction at a current density of 10 mA cm⁻¹ -2 The potential (E) j＝10 The voltage was 1.455V. The final product was coated onto nickel foam and used as both the cathode and anode, with a 1M KOH solution as the electrolyte. The water electrolysis performance was tested, achieving a voltage of 10 mA cm⁻¹. -2 The water splitting current density requires only a potential of 1.545V;

[0097] Catalytic performance testing under acidic conditions: In a 0.5 M H₂SO₄ system, the HER reaction was performed at a current density of 10 mA / cm⁻¹. -2 Overpotential (η) j＝10 The voltage was 52.1 mV; the OER reaction at a current density of 10 mA cm⁻¹ -2 The potential (E) j＝10The voltage was 1.432V. The final product was coated onto nickel foam and used as both the cathode and anode, with a 1M KOH solution as the electrolyte. The water electrolysis performance was tested, achieving 10 mA / cm². -2 The water splitting current density requires a potential of only 1.536V, as shown in Table 1:

[0098] Table 1

[0099]

[0100] As shown in Table 1, based on the examples and comparative examples 1-4, the described process can obtain electrocatalytic materials that are resistant to acids and alkalis and also exhibit excellent HER and OER performance. Furthermore, as shown in Examples 1 and 2, the molten salt combination described in this invention, when combined with the process of this invention, can achieve better synergy and superior synergistic performance. Moreover, as shown in Examples 1, 3-5, the use of the preferred carbon source, preferred metal source, and preferred additives described in this invention can also enhance technical synergy and further optimize the material's performance. As shown in Examples 1 and 6, rapid quenching with liquid nitrogen helps to further optimize the physicochemical structure of the material, resulting in better electrocatalytic activity.

Claims

1. A method for preparing a hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst, characterized in that, The mixed raw materials containing molten salt, carbon source, transition metal source, phosphorus source and auxiliary agent are preheated at a first temperature T1, then heated to a second temperature T2 and preheated again, to obtain a precursor material; the precursor material is subjected to quenching treatment to obtain the hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst. The auxiliary agent comprises at least one of phytic acid, oxalic acid and citric acid. The first temperature T1 is 200-450℃, and the second temperature T2 is 850-1200℃.

2. The preparation method of the hierarchical porous carbon / crystalline amorphous dual-phase metal phosphide composite electrocatalyst as described in claim 1, characterized in that, The molten salt comprises at least one of sodium chloride, potassium chloride, potassium nitrate, sodium carbonate, ammonium nitrate, calcium fluoride, magnesium fluoride and aluminum fluoride.

3. The method of producing a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst according to claim 2, wherein The molten salt comprises two or more of sodium chloride, potassium chloride, potassium nitrate, sodium carbonate, ammonium nitrate, calcium fluoride, magnesium fluoride and aluminum fluoride.

4. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 1, wherein, The carbon source comprises at least one of inorganic carbon and organic carbon source.

5. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 4, wherein, The organic carbon source comprises at least one of monosaccharide compound, disaccharide compound, polysaccharide and polymer.

6. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 1, wherein, The transition metal source comprises two or more transition metal elements.

7. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 6, wherein, The transition metal source comprises two or more of iron, nickel and cobalt.

8. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 1, wherein, The phosphorus source is at least one of calcium hydrogen phosphate, potassium dihydrogen phosphate, superphosphate and ammonium phosphate.

9. The method of making a hierarchically porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst of claim 1, wherein, The weight ratio of the transition metal source, molten salt, carbon source and auxiliary agent is 1:2-5:5-15:0.5-3; and the molar ratio of transition metal elements in the transition metal source to P element in the phosphorus source is 1:0.2-2.

10. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 1, wherein, The mixed raw materials are obtained by liquid-phase mixing of molten salt, carbon source, transition metal source, phosphorus source and auxiliary agent and then desolventizing.

11. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 10, wherein, The desolventizing means is spraying.

12. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 1, wherein, The preheating time of the first preheating is 1-5h.

13. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 1, wherein, The preheating time of the second preheating is 1-5h.

14. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 1, wherein, The cooling medium selected in the quenching stage is a liquid medium with a temperature below 30℃.

15. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 14, wherein, The cooling medium selected in the quenching stage is water or liquid nitrogen.

16. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 1, 14 or 15, wherein, In the quenching stage, the temperature difference between the precursor material and the quenching medium is above 500℃.

17. The method of making a hierarchically porous carbon / crystalline-amorphous dual phase metal phosphide composite electrocatalyst of claim 16, wherein, The method further comprises a step of carbon-coating the hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst.

18. A hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst prepared by the preparation method of any one of claims 1-17.

19. The use of the hierarchical porous carbon / crystalline-amorphous bi-phase metal phosphide composite electrocatalyst prepared by the method of any one of claims 1-17, characterized in that, The hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst is used as a catalytic material for water electrocatalysis.

20. A water electrocatalytic device, characterized by, The hierarchical porous carbon / crystalline-amorphous dual-phase metal phosphide composite electrocatalyst is prepared by the preparation method of any one of claims 1-17.

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