Trimetallic-based nanoparticle electrocatalytic whole-hydrolysis material, preparation method and application thereof

Abstract

This invention belongs to the field of electrocatalysis technology, specifically relating to a method for preparing a trimetallic nanoparticle electrocatalytic water splitting material. Using a linear [M3(COO)6] trinuclear cluster-based metal-organic framework as a precursor, a one-step pyrolysis under an inert gas atmosphere yields a low-cost, high-efficiency catalyst. Ni, Co, and Fe metal ions are simultaneously and uniformly distributed within the trinuclear cluster of the precursor, and pyrolysis forms a homogeneous coexistence of multiple crystalline phases such as Co2NiO4, FeFe2O4, CoO, FeNi, FeNi, and Ni. At high temperatures, the precursor transforms into amorphous porous carbon, promoting the uniform dispersion of metal nanoparticles and generating abundant catalytic active sites. It also provides a protective outer shell that promotes electrolyte migration, enhances catalyst conductivity, and improves catalyst stability. This electrocatalyst can be used simultaneously as both a cathode and anode materials in fuel cells and electrolyzers for energy conversion and large-scale industrial hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a trimetallic nanoparticle electrocatalytic total water splitting material, its preparation method, and its application. Background Technology

[0002] In response to the increasingly severe global environmental pollution and energy crisis, finding new renewable energy sources to replace traditional fossil fuels is an urgent task. Hydrogen, with its high energy density and zero pollution, is one of the most promising energy carriers for the future. Utilizing electrocatalytic water splitting technology to convert intermittent and unstable photovoltaic and wind power into hydrogen is key to achieving large-scale storage and application of green energy. This necessitates efficient, inexpensive, and readily available electrocatalysts to improve energy conversion efficiency and ensure economic feasibility. Traditional electrocatalysts based on precious metals such as platinum, ruthenium, and Ir exhibit good catalytic efficiency for hydrogen evolution and oxygen evolution reactions, but their inherent scarcity and high cost make them unsuitable for large-scale applications. Designing novel electrocatalysts based on abundant, inexpensive, environmentally friendly, and uniquely electronically structured 3d transition metals such as Fe, Co, and Ni is a major technological trend. However, traditional 3d metal oxide and hydroxide electrocatalysts, mainly prepared through chemical precipitation-high-temperature calcination, are mostly bulk and single-metal-based materials, and their performance parameters, such as overpotential, Tafel slope, conversion frequency, catalyst durability, and lifespan, are far from ideal. Furthermore, due to the significant differences in the intrinsic mechanisms and reaction kinetics of hydrogen evolution and oxygen evolution reactions, most known 3d metal electrocatalysts are only effective for a single reaction in hydrogen evolution or oxygen evolution, making it difficult to achieve dual functionality and complete hydrolysis, which greatly increases the complexity and cost of electrolytic cells. Summary of the Invention

[0003] The purpose of this invention is to provide a trimetallic nanoparticle electrocatalytic hydrolysis material, its preparation method and application, which solves the problem that traditional 3d metal catalysts have poor catalytic activity and are difficult to achieve hydrogen evolution and oxygen evolution dual-function hydrolysis at the same time.

[0004] This invention is achieved through the following technical solution:

[0005] A trimetallic nanoparticle electrocatalytic total water splitting material, wherein the trimetallic nanoparticle electrocatalytic total water splitting material comprises Ni, Co, and Fe trimetallic nanoparticles, which are uniformly dispersed in porous amorphous carbon, and have the chemical formula NiCoFeOx@C;

[0006] By mass percentage, the metal content of the trimetallic nanoparticles is as follows: Ni 40%–50%, Co 30%–40%, and Fe 10%–30%.

[0007] Furthermore, the trimetallic nanoparticles contain uniformly distributed Co2NiO4, FeFe2O4, CoO, FeNi, FeNi and Ni multi-phase crystals.

[0008] Furthermore, the specific surface area of ​​the trimetallic nanoparticle electrocatalytic total water splitting material exceeds 90 m². 2 / g, with a pore size distribution of 1nm micropores and 3-8nm wide-distributed mesopores.

[0009] Furthermore, the trimetallic nanoparticles have a size of 5-15 nm.

[0010] This invention also discloses a method for preparing the trimetallic nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0011] Using metal-organic framework NiCoFe-MOF as a precursor, the material was pyrolyzed at 350-450℃ for 0.5-2 h under an inert gas atmosphere, and then cooled to obtain a trimetallic nanoparticle electrocatalytic total hydrolysis material.

[0012] Furthermore, the metal-organic framework NiCoFe-MOF is a porous network structure composed of a linear [M3(COO)6] trinuclear cluster and [1,1'-biphenyl]-3,4',5-tricarboxylic acid (3,6) connected together, with the cluster core containing Ni, Co and Fe metal ions simultaneously.

[0013] This invention also discloses the application of the aforementioned trimetallic nanoparticle electrocatalytic total water splitting material, which serves as a catalyst for the electrocatalytic oxygen evolution reaction in a 1M KOH electrolyte at 10 mA cm⁻¹. -2 At current density, the overpotential is as low as 253 mV, and the Tafel slope is as low as 83 mV dec. -1 .

[0014] This invention also discloses the application of the aforementioned trimetallic nanoparticle electrocatalytic total water splitting material. As a catalyst for the electrocatalytic hydrogen evolution reaction, the trimetallic nanoparticle electrocatalytic total water splitting material exhibits an overpotential as low as 84 mV and a Tafel slope as low as 113 mV dec in a 1 M KOH electrolyte. -1 .

[0015] This invention also discloses the application of the aforementioned trimetallic nanoparticle electrocatalytic total water splitting material, which is used as a catalyst supported on nickel foam and serves as the cathode and anode electrodes of an electrolytic cell. In a 1M KOH electrolyte, at a voltage of 1.71V and a current of 10mA, the electrolytic total water splitting material is used... -2 At a current density, water is simultaneously decomposed into hydrogen and oxygen, and the catalytic performance remains stable for more than 20 hours.

[0016] Furthermore, the preparation process of loading the catalyst onto nickel foam as the cathode and anode electrodes of the electrolytic cell is as follows:

[0017] Mix 5 mg of electrocatalytic material, 1 mg of carbon black, 970 μL of anhydrous ethanol, and 30 μL of Nafion solution evenly, and sonicate for 30 min to prepare a suspension.

[0018] The suspension was dropped onto the surface of nickel foam and allowed to air dry naturally to prepare the catalyst-supported anode and cathode electrodes.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention discloses a trimetallic nanoparticle electrocatalytic all-water-splitting material, characterized by 5-15 nm ultra-small nanoparticles uniformly distributed within an amorphous porous carbon layer, providing abundant metal catalytic active sites for the electrocatalytic reaction. Due to the presence of the outer amorphous porous carbon layer, the catalyst exhibits excellent porosity, with a specific surface area exceeding 90 m². 2 / g, with a main pore size distribution of 1nm micropores and 3-8nm wide-distributed mesopores, fully exposes abundant catalytic active sites and provides a protective layer that facilitates electrolyte migration and enhances the conductivity of the catalyst, ensuring the stability and durability of the catalyst.

[0021] The electrocatalytic material exhibits superior performance, demonstrating higher catalytic efficiency and a faster electrochemical reaction rate compared to commercial RuO2: in 1M KOH electrolyte, at 10 mA cm⁻¹ -2 At current density, the oxygen evolution reaction overpotential is as low as 253 mV, and the Tafel slope is as low as 83 mV dec. -1 The hydrogen evolution reaction overpotential is as low as 84 mV, and the Tafel slope is as low as 113 mV dec. -1 It features dual oxygen and hydrogen evolution functions, requiring only a low voltage of 1.71V to operate at 10mA. -2 At a current density, water is simultaneously decomposed into hydrogen and oxygen. The material exhibits good structural stability and durability, and its catalytic performance can be stably maintained for more than 20 hours.

[0022] Furthermore, the trimetallic nanoparticles are composed of a mixture of multiple crystalline phases such as Co2NiO4, FeFe2O4, CoO, FeNi and Ni. The coexistence of multiple components, multimetal composite and rich heterojunction interfaces promote the realization of hydrogen evolution and oxygen evolution dual functions and significantly improve the catalytic efficiency of the material.

[0023] This invention discloses a method for preparing a trimetallic nanoparticle electrocatalytic hydrolysis material. Using a metal-organic framework NiCoFe-MOF as a precursor, the material is pyrolyzed at 350-450℃ for 0.5-2 hours under an inert gas atmosphere to obtain a highly efficient catalyst. Ni, Co, and Fe metal ions are uniformly distributed simultaneously in a trinuclear cluster. Under heat treatment, the metal ions aggregate and undergo structural transformation, forming trimetallic nanoparticles with uniformly coexisting multi-phase crystalline structures such as Co₂NiO₄, FeFe₂O₄, CoO, FeNi, FeNi, and Ni. The moderate heat treatment at 350-450℃ effectively reduces the agglomeration of the metal nanoparticles, yielding ultra-small nanocatalysts with sizes of 5-15 nm. The coexistence of multiple components enables the material to simultaneously catalyze hydrogen evolution and oxygen evolution reactions. The multi-metal composite and abundant heterojunction interfaces significantly enhance the catalytic efficiency. Metal-organic frameworks are porous coordination networks assembled from metal ions and organic ligands through coordination bonds, possessing outstanding characteristics such as designable structure, easily tunable composition, and high porosity. Metal-organic frameworks (MOFs) can serve as excellent precursor templates, enabling the preparation of novel micro / nano-scale, morphology-controllable, multi-metal composite, and heterojunction-interface synergistic electrocatalysts through simple pyrolysis post-processing, achieving high catalytic efficiency and complete water splitting. This method offers a series of advantages, including simple equipment, rapid reaction, mild conditions, and high yield. The meso-temperature pyrolysis at 350-450℃ significantly inhibits the aggregation of metal nanoparticles, promoting the formation of ultra-small, uniform nanoparticles. Compared to traditional high-temperature and ultra-high-temperature pyrolysis methods, it also greatly saves on thermal and electrical energy consumption. The prepared Ni, Co, and Fe trimetallic nanoparticle catalysts exhibit significantly superior performance and are far less expensive than traditional noble metal electrocatalysts, making them easy to scale up for large-scale production and possessing significant industrial application value and prospects.

[0024] Furthermore, the polycyclic carboxylic acid organic ligands of the metal-organic framework are decarboxylated and transformed into amorphous porous carbon at high temperatures. This not only restricts the trimetallic nanoparticles from maintaining their ultra-small size and uniform particle size distribution, but also provides a protective shell layer that promotes electrolyte migration and enhances the conductivity of the catalyst, thereby improving the stability and durability of the catalyst.

[0025] This invention also discloses the application of the trimetallic nanoparticle electrocatalytic hydrolysis material, which can be used as a catalyst coated on a nickel foam electrode to catalyze the oxygen evolution reaction, or as a catalyst coated on a nickel foam electrode to catalyze the hydrogen evolution reaction; it can also be used as both a cathode and anode material in fuel cells and electrolyzers for energy conversion and large-scale industrial hydrogen production. Attached Figure Description

[0026] Figure 1 The powder diffraction pattern of the NiCoFe-MOF precursor is shown below.

[0027] Figure 2Thermogravimetric curve of the NiCoFe-MOF precursor;

[0028] Figure 3 The powder diffraction pattern of the NiCoFe@C-400 is shown below.

[0029] Figure 4 This is a TEM image of NiCoFe@C-400 described in this invention;

[0030] Figure 5 The N2 adsorption curve of NiCoFe@C-400 is shown below.

[0031] Figure 6 The pore size distribution diagram of the NiCoFe@C-400 is shown below.

[0032] Figure 7 The OER polarization curve of the NiCoFe@C-400 is shown below.

[0033] Figure 8 The OER polarization curve of the NiCoFe@C-400 is shown below.

[0034] Figure 9 The HER polarization curve of the trimetallic nanoparticle electrocatalytic material is shown below.

[0035] Figure 10 The HER Tafel slope diagram of the trimetallic nanoparticle electrocatalytic material is shown below.

[0036] Figure 11 The OER polarization curves of NiCoFe@C-350 and NiCoFe@C-450 are shown below;

[0037] Figure 12 OER Tafel slope plots for NiCoFe@C-350 and NiCoFe@C-450;

[0038] Figure 13 The graph shows the total hydrolysis polarization curve of the NiCoFe@C.

[0039] Figure 14 The constant-voltage electrocatalytic stability of the NiCoFe@C-400 is given. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0041] The descriptions of the embodiments and accompanying drawings of this invention can be implemented in various different configurations. Therefore, the detailed description of the embodiments provided in the following drawings is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment. All other embodiments obtained by those skilled in the art based on the accompanying drawings and embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0042] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0043] Example 1

[0044] This invention discloses a method for preparing a trimetallic-based nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0045] (1) NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O, and [1,1'-biphenyl]-3,4',5-tricarboxylic acid were weighed out in a molar ratio of 0.1:0.1:0.1:0.25 and dissolved in a mixed solution of 14 mL DMF, 2 mL H2O, and 2 mL EtOH. After stirring the mixture thoroughly, it was transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was reacted in a constant temperature oven at 140℃ for 72 h. After cooling to room temperature, it was filtered and washed to obtain rod-shaped crystals, which are the metal-organic framework precursor NiCoFe-MOF.

[0046] (2) Weigh 50 mg of the precursor NiCoFe-MOF and place it in a ceramic boat. Transfer the boat to a tube furnace, introduce N2 gas, and heat the furnace to 400 °C at a rate of 5 °C / min and keep it at that temperature for 2 h. Cool the furnace to room temperature at a rate of 5 °C / min under a nitrogen atmosphere. Grind the sample evenly to obtain a trimetallic nanoparticle electrocatalytic material, denoted as NiCoFeOx@C-400.

[0047] The metal content ratio of the trimetallic nanoparticle electrocatalytic material NiCoFeOx@C prepared in this embodiment is 42% Ni, 41% Co, and 17% Fe.

[0048] Example 2

[0049] This invention discloses a method for preparing a trimetallic-based nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0050] (1) NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O, and [1,1'-biphenyl]-3,4',5-tricarboxylic acid were weighed out in a molar ratio of 0.1:0.05:0.05:0.25 and dissolved in a mixed solution of 14 mL DMF, 2 mL H2O, and 2 mL EtOH. After the mixture was stirred evenly, it was transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was reacted in a constant temperature oven at 140℃ for 72 h. After cooling to room temperature, it was filtered and washed to obtain rod-shaped crystals, which are the metal-organic framework precursor NiCoFe-MOF.

[0051] (2) Weigh 50 mg of the precursor NiCoFe-MOF and place it in a ceramic boat. Transfer the boat to a tube furnace, introduce N2 gas, and heat the furnace to 400 °C at a rate of 5 °C / min and keep it at that temperature for 2 h. Cool the furnace to room temperature at a rate of 5 °C / min under a nitrogen atmosphere. Grind the sample evenly to obtain a trimetallic nanoparticle electrocatalytic material, denoted as NiCoFeOx@C-400.

[0052] The metal content ratio of the trimetallic nanoparticle electrocatalytic material NiCoFeOx@C prepared in this embodiment is 50% Ni, 30% Co, and 20% Fe.

[0053] Example 3

[0054] This invention discloses a method for preparing a trimetallic-based nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0055] (1) NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O, and [1,1'-biphenyl]-3,4',5-tricarboxylic acid were weighed out in a molar ratio of 0.1:0.1:0.1:0.25 and dissolved in a mixed solution of 14 mL DMF, 2 mL H2O, and 2 mL EtOH. After stirring the mixture thoroughly, it was transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was reacted in a constant temperature oven at 140℃ for 72 h. After cooling to room temperature, it was filtered and washed to obtain rod-shaped crystals, which are the metal-organic framework precursor NiCoFe-MOF.

[0056] (2) Weigh 50 mg of the precursor NiCoFe-MOF and place it in a ceramic boat. Transfer the boat to a tube furnace, introduce N2 gas, and heat the furnace to 350 °C at a rate of 5 °C / min and keep it at that temperature for 2 h for pyrolysis. Cool the furnace to room temperature at a rate of 10 °C / min under a nitrogen atmosphere. Grind the sample evenly to obtain a trimetallic nanoparticle electrocatalytic material, denoted as NiCoFeOx@C-350.

[0057] The metal content ratio of the trimetallic nanoparticle electrocatalytic material NiCoFeOx@C prepared in this embodiment is 42% Ni, 41% Co, and 17% Fe.

[0058] Example 4

[0059] This invention discloses a method for preparing a trimetallic-based nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0060] (1) NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O, and [1,1'-biphenyl]-3,4',5-tricarboxylic acid were weighed out in a molar ratio of 0.1:0.1:0.1:0.25 and dissolved in a mixed solution of 14 mL DMF, 4 mL H2O, and 4 mL EtOH. After the mixture was stirred evenly, it was transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The mixture was reacted in a constant temperature oven at 140℃ for 72 h. After cooling to room temperature, it was filtered and washed to obtain rod-shaped crystals, which is the metal-organic framework precursor NiCoFe-MOF.

[0061] (2) Weigh 200 mg of the precursor NiCoFe-MOF and place it in a ceramic boat. Transfer the boat to a tube furnace, introduce N2 gas, and heat the furnace to 450 °C at a rate of 2 °C / min and hold for 1 h for pyrolysis. Cool the furnace to room temperature at a rate of 10 °C / min under a nitrogen atmosphere. Grind the sample evenly to obtain a trimetallic nanoparticle electrocatalytic material, denoted as NiCoFeOx@C-450.

[0062] The metal content ratio of the trimetallic nanoparticle electrocatalytic material NiCoFeOx@C prepared in this embodiment is 42% Ni, 41% Co, and 17% Fe.

[0063] Example 5

[0064] This invention discloses a method for preparing a trimetallic-based nanoparticle electrocatalytic total water splitting material, comprising the following steps:

[0065] (1) NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O, and [1,1'-biphenyl]-3,4',5-tricarboxylic acid were weighed out in a molar ratio of 0.2:0.1:0.1:0.25 and dissolved in a mixed solution of 15 mL DMF, 1 mL H2O, and 1 mL EtOH. After the mixture was stirred evenly, it was transferred to a stainless steel reactor with a polytetrafluoroethylene liner. The reaction was carried out in a constant temperature oven at 140℃ for 72 h. After cooling to room temperature, the mixture was filtered and washed to obtain rod-shaped crystals, which are the metal-organic framework precursor NiCoFe-MOF.

[0066] (2) Weigh 100 mg of the precursor NiCoFe-MOF and place it in a ceramic boat. Transfer the boat to a tube furnace, introduce Ar gas, and heat the furnace to 450 °C at a rate of 5 °C / min and hold for pyrolysis for 0.5 h. Cool the furnace to room temperature at a rate of 5 °C / min under the Ar atmosphere. Grind the sample evenly to obtain a trimetallic nanoparticle electrocatalytic material, denoted as NiCoFeOx@C-450.

[0067] The metal content ratio of the trimetallic nanoparticle electrocatalytic material NiCoFeOx@C prepared in this embodiment is 60% Ni, 24% Co, and 16% Fe.

[0068] Examples 1-5 utilize metal-organic frameworks as templates and precursors, inducing their transformation into multi-component metal catalyst carbon composite materials via a one-step intermediate-temperature pyrolysis method, effectively reducing the aggregation of metal nanoparticles. The resulting multi-component metal catalyst carbon composite materials exhibit excellent hydrogen evolution and oxygen evolution performance, and can be directly coated onto electrode surfaces to achieve complete hydrolysis, demonstrating significant application value in energy conversion and large-scale hydrogen production.

[0069] The application of the multi-component metal catalyst carbon composite material of the present invention in the field of hydrogen evolution is specifically as follows:

[0070] Application Example 1

[0071] (1) Weigh 5 mg of the multi-component metal catalyst carbon composite material NiCoFe@C and 1 mg of carbon black, and grind them thoroughly using a mortar and pestle;

[0072] (2) Place the ground powder in a 3 mL centrifuge tube, and use a pipette to transfer 970 μL of ethanol solution and 30 μL of 5 wt% Nafion solution. Sonicate for half an hour to form a uniformly dispersed suspension.

[0073] (3) Take 14 μL of the above suspension and add it dropwise to the surface of the acid-treated nickel foam, let it air dry naturally, and prepare nickel foam supported on NiCoFeOx@C catalyst;

[0074] (4) Using nickel foam supported on NiCoFe@C catalyst as the working anode and graphite electrode as the cathode, and 1 M KOH solution as the electrolyte, a 10 mA cm⁻¹ can be obtained when the applied voltage exceeds 85 mV. -2 The current density is stable and hydrogen is produced.

[0075] The application of the multi-component metal catalyst carbon composite material of the present invention in the field of oxygen evolution is specifically as follows:

[0076] Application Example 1

[0077] (1) Weigh 5 mg of the multi-component metal catalyst carbon composite material NiCoFe@C and 1 mg of carbon black, and grind them thoroughly using a mortar and pestle;

[0078] (2) Place the ground powder in a 3 mL centrifuge tube, and use a pipette to transfer 970 μL of ethanol solution and 30 μL of 5 wt% Nafion solution. Sonicate for half an hour to form a uniformly dispersed suspension.

[0079] (3) Take 14 μL of the above suspension and add it dropwise to the surface of the acid-treated nickel foam, let it air dry naturally, and prepare nickel foam supported on NiCoFeOx@C catalyst;

[0080] (4) Using nickel foam supported on NiCoFe@C catalyst as the working anode and platinum sheet electrode as the cathode, and using 1 M KOH solution as the electrolyte, a 10 mA cm⁻¹ can be obtained when the applied voltage exceeds 253 mV. -2 The current density is stable and oxygen is produced.

[0081] The application of the multi-component metal catalyst carbon composite material of the present invention in the preparation of bifunctional electrodes and in the field of total water splitting is specifically as follows:

[0082] Application Example 3

[0083] (1) Weigh 5 mg of the multi-component metal catalyst carbon composite material NiCoFe@C and 1 mg of carbon black, and grind them thoroughly using a mortar and pestle;

[0084] (2) Place the ground powder in a 3 mL centrifuge tube, and use a pipette to transfer 970 μL of ethanol solution and 30 μL of 5 wt% Nafion solution. Sonicate for half an hour to form a uniformly dispersed suspension.

[0085] (3) Take 25 μL of the above suspension and add it dropwise to the surface of the acid-treated nickel foam, let it air dry naturally, and prepare nickel foam supported on NiCoFe@C catalyst;

[0086] (4) Using nickel foam supported on NiCoFe@C catalyst as the working anode and cathode, respectively, and using 1M KOH solution as the electrolyte, a 10mA cm⁻¹ can be obtained when the applied voltage exceeds 1.71V. -2 It can maintain a stable current density and continuously produce hydrogen and oxygen, and its catalytic performance can be maintained for more than 20 hours.

[0087] Appendix Figure 1 The image shows the powder diffraction pattern of NiCoFe-MOF. The precursor NiCoFe-MOF is in perfect agreement with its simulated pattern, indicating the preparation of a high-purity phase of NiCoFe-MOF.

[0088] As attached Figure 2 As shown, the weight loss of NiCoFe-MOF from room temperature to 200℃ corresponds to the departure of water and DMF solvent molecules, while the drastic weight loss from 340℃ to 540℃ corresponds to the pyrolysis of MOF and the formation of nanoparticles and porous carbon.

[0089] As attached Figure 3 As shown, NiCoFe@C-400 obtained by pyrolysis at 400℃ mainly exists in the form of Co2NiO4, FeFe2O4, CoO, FeNi and Ni multi-phase crystals.

[0090] As attached Figure 4 As shown, high-resolution TEM images of NiCoFe@C-400 reveal that (ac) the metal nanoparticles are uniformly distributed within the amorphous carbon structure; (d) the ternary metal nanoparticles have a diameter of approximately 5-15 nm; and (e) each nanoparticle simultaneously contains Ni (JCPDS no. 45-1027), FeNi (JCPDS no. 37-0474), CoO (JCPDS no. 48-1719), and (FeNi). 23 (f) Summary table of crystal phases present in nanoparticles, including C6 (JCPDS no. 25-0405), Co2NiO4 (JCPDS no. 02-1074), and FeFe2O4 (JCPDS no. 28-0491).

[0091] As attached Figure 5 As shown, NiCoFe@C-400 exhibits a typical type IV nitrogen adsorption curve, indicating that the catalyst is a typical porous material with a Langmuir specific surface area of ​​93.5 m². 2 g -1 This provides abundant active sites for electrochemical reactions and also facilitates electrolyte migration and protects the catalyst.

[0092] As attached Figure 6 As shown, the main pore size distribution of NiCoFe@C-400 consists of 1 nm micropores and 3–8 nm wide-distributed mesopores.

[0093] Appendix Figure 7 The image shows the OER polarization curve of NiCoFe@C-400. NiCoFe@C-400 has a low overpotential of 253 mV, which is significantly better than commercial RuO2.

[0094] Appendix Figure 8 The OER Tafel slope diagram for NiCoFe@C-400 shows that the Tafel slope of NiCoFe@C-400 is 83.3 mV / dec, which is better than the Tafel slope of commercial RuO2 (135.7 mV / dec). NiCoFe@C has a faster electrochemical reaction rate than commercial RuO2.

[0095] Appendix Figure 9 The image shows the HER polarization curve of NiCoFe@C. The overpotential of NiCoFe@C-400 is 85mV.

[0096] Appendix Figure 10 The HER Tafel slope plot for NiCoFe@C is shown. The Tafel slope for NiCoFe@C-400 is 113.2 mV / dec.

[0097] Appendix Figure 11 The OER polarization curves of NiCoFe@C-350 and NiCoFe@C-450 are shown. NiCoFe@C-350 has a low overpotential of 257 mV, and NiCoFe@C-450 has a low overpotential of 259 mV.

[0098] Appendix Figure 12 The OER Tafel slope plots for NiCoFe@C-350 and NiCoFe@C-450 are shown. The Tafel slope for NiCoFe@C-350 is 53.9 mV / dec, and the Tafel slope for NiCoFe@C-450 is 78.9 mV / dec.

[0099] Appendix Figure 13 The complete hydrolysis polarization curve of NiCoFe@C shows that a stable 10 mA cm⁻¹ voltage can be provided with only a low voltage of 1.71 V. -2 The current density.

[0100] Appendix Figure 14 The constant-voltage electrocatalytic stability of NiCoFe@C-400 showed no significant change in time-dependent overpotential over 20 hours, demonstrating the excellent structural stability and durability of the catalyst.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A trimetallic-based nanoparticle electrocatalytic total water splitting material, characterized in that, The trimetallic nanoparticle electrocatalytic hydrolysis material contains Ni, Co, and Fe trimetallic nanoparticles, which are uniformly dispersed in porous amorphous carbon, with the chemical formula NiCoFeOx@C. By mass percentage, the metal content of the trimetallic nanoparticles is as follows: Ni 40%~50%, Co 30%~40%, and Fe 10%~30%. The trimetallic nanoparticles contain uniformly distributed Co2NiO4, FeFe2O4, CoO, FeNi, FeNi and Ni multi-phase crystals; The specific surface area of ​​the trimetallic nanoparticle electrocatalytic hydrolysis material exceeds 90 m². 2 / g, with a pore size distribution of 1 nm micropores and 3~8 nm wide-distributed mesopores.

2. The trimetallic-based nanoparticle electrocatalytic total water splitting material according to claim 1, characterized in that, The size of the trimetallic nanoparticles is 5-15 nm.

3. The method for preparing the trimetallic-based nanoparticle electrocatalytic total water splitting material according to claim 1 or 2, characterized in that, The process includes the following: Using NiCoFe-MOF as a precursor, under an inert gas atmosphere at 350-450 °C... o Pyrolysis at C for 0.5~2h, followed by cooling, yields a trimetallic nanoparticle electrocatalytic hydrolysis material. The metal-organic framework NiCoFe-MOF is a porous network structure composed of linear [M3(COO)6] trinuclear clusters and [1,1'-biphenyl]-3,4',5-tricarboxylic acid (3,6) linked together. The cluster cores contain Ni, Co and Fe metal ions.

4. The application of the trimetallic-based nanoparticle electrocatalytic total water splitting material according to any one of claims 1 or 2, characterized in that, The trimetallic nanoparticle electrocatalytic total water splitting material was used as a catalyst for the electrocatalytic oxygen evolution reaction in a 1 M KOH electrolyte at 10 mA cm⁻¹. -2 At current density, the overpotential is as low as 253 mV, and the Tafel slope is as low as 83 mV dec. -1 .

5. The application of the trimetallic-based nanoparticle electrocatalytic total water splitting material according to any one of claims 1 or 2, characterized in that, The trimetallic nanoparticle electrocatalytic total water splitting material was used as a catalyst for the electrocatalytic hydrogen evolution reaction in a 1 M KOH electrolyte at 10 mA cm⁻¹. -2 At current density, the overpotential is as low as 84 mV, and the Tafel slope is as low as 113 mV dec. -1 .

6. The application of the trimetallic-based nanoparticle electrocatalytic total water splitting material according to any one of claims 1 or 2, characterized in that, The trimetallic nanoparticle electrocatalytic total water splitting material was supported on nickel foam as a catalyst and served as the cathode and anode electrodes of the electrolytic cell, respectively. In a 1 M KOH electrolyte, at a voltage of 1.71 V and a 10 mA cm⁻¹ temperature, the electrolysis was performed. 2 At a current density, water is simultaneously decomposed into hydrogen and oxygen, and the catalytic performance remains stable for more than 20 hours.

7. The application of the trimetallic-based nanoparticle electrocatalytic total water splitting material according to claim 6, characterized in that, The preparation process of catalyst supported on nickel foam as the cathode and anode electrodes of the electrolytic cell is as follows: Mix 5 mg of electrocatalytic material, 1 mg of carbon black, 970 µL of anhydrous ethanol, and 30 µL of Nafion solution evenly, and sonicate for 30 min to prepare a suspension. The suspension was dropped onto the surface of nickel foam and allowed to air dry naturally to prepare the catalyst-supported anode and cathode electrodes.

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