阅读说明：本技术 一种燃料电池阴极多金属掺杂多元非金属氧还原催化剂及其制备方法 (Fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst and preparation method thereof ) 是由 崔大祥 李梦飞 刘鹏飞 周霖 李天昊 葛美英 张芳 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种燃料电池阴极多金属掺杂多元非金属氧还原催化剂及其制备方法,本发明的多金属与N、F的复合掺杂碳载体,增强导电性和比表面积,有利于促进氧还原反应过程中的电子转移过程；操作简单且制得的氧还原催化剂半波电位数值较高,催化剂的活性较高。(The invention discloses a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst and a preparation method thereof, the multi-metal and N, F composite doped carbon carrier of the invention enhances the conductivity and the specific surface area, and is beneficial to promoting the electron transfer process in the oxygen reduction reaction process; the operation is simple, the prepared oxygen reduction catalyst has a high half-wave potential value, and the activity of the catalyst is high.)

1. A preparation method of a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is characterized by comprising the following steps:

(1) uniformly mixing a mixed solution of graphene oxide and palladium chloride prepared according to the mass ratio of (1: 0.005-0.0625) with a mixed solution of N, F-containing nonmetal salt or N, F-containing organic matter and transition metal salt to obtain a dispersion liquid; preparing a mixed solution of graphene oxide and palladium chloride according to the mass ratio of 1 (0.005-0.0625), and uniformly mixing the mixed solution with N, F-containing nonmetal salt or N, F-containing organic matter and transition metal salt to obtain a dispersion liquid; wherein the volume ratio of the graphene oxide solution to the solvent of the mixed solution is 1 (2-3); the mass ratio of the graphene oxide to the nonmetal salt containing N, F or the organic matter containing N, F to the nonmetal elements is 1 (0.01-0.125); the molar ratio of the nonmetal element of the N, F-containing nonmetal salt or N, F-containing organic matter to the metal in the transition metal salt is 1 (0.01-10);

(2) and (3) carrying out suction filtration and separation on the dispersion liquid to obtain a solid, and drying and carrying out heat treatment on the solid to obtain the multi-metal doped multi-element non-metal oxygen reduction catalyst.

2. The method for preparing the fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst according to claim 1, wherein in the step (1), the graphene oxide is in a solution; and/or the solvent in the mixed solution is glycol solvent; and/or, in the mixed solution, the concentration of the graphene oxide is 0.3-0.6 mg/mL; and/or, the mixed solution is prepared by the following steps: fully stirring and mixing by magnetic stirring, and then carrying out ultrasonic dispersion on the mixed solution to be uniform under the ultrasonic condition.

3. The method for preparing the fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst according to claim 2, wherein in the step (1), the graphene oxide is a solution which is subjected to stirring dialysis in deionized water through a semipermeable bio-membrane;

and/or in the step (1), the solvent in the mixed solution is glycol;

and/or in the step (1), the concentration of the graphene oxide in the mixed solution is 0.4 mg/mL;

and/or, in the step (1), wherein the magnetic stirring time is 2-4 hours;

and/or, in the step (1), the time of ultrasonic dispersion is 20-40 min.

4. The method of claim 1 or 2, wherein in step (1), the N, F-containing non-metal salt or N, F-containing organic, transition metal salt is added by the following steps:

under the condition of magnetic stirring, the non-metal salt containing N, F or the organic matter containing N, F and the transition metal salt are dripped into the mixed solution, and the mixed solution is fully stirred by magnetic stirring and then is dispersed by ultrasonic until the mixed solution is uniform.

5. The method of claim 4, wherein the transition metal salt is a cobalt salt, iron salt and/or nickel salt; wherein the transition metal salt is present in the form of a nitrate or a hydrochloride.

6. The method of claim 4, wherein the magnetic stirring time is 2-4 hours, preferably 3 hours;

and/or, in the step (1), the time of ultrasonic dispersion is 20-40min, preferably 30 min;

and/or in the step (1), the transition metal salt is one or more of cobalt nitrate, ferrous nitrate, cobalt nitrate and nickel chloride;

and/or in the step (1), the N, F-containing nonmetal salt or N, F-containing organic matter is one or more of ammonium bifluoride, urea, pyridine, ammonia water and hydrofluoric acid.

7. The method for preparing the fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst according to claim 1, wherein in the step (1), the volume ratio of the graphene oxide solution to the solvent of the mixed solution is 1: 2-3; and/or in the step (1), the mass ratio of the graphene oxide to the palladium chloride is (1: 0.005-0.0625);

and/or in the step (1), the mass ratio of the non-metal elements of the graphene oxide and the non-metal salt containing N, F or the organic matter containing N, F is (1: 0.01-0.125);

and/or in the step (1), the molar ratio of the nonmetal elements of the N, F-containing nonmetal salt or N, F-containing organic substance to the metals in the transition metal salt is (1: 0.01-10).

8. The method for preparing the fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst according to claim 1, wherein in the step (1), the mixing reaction time is 6-14h, preferably 8-12h, for example 10 h;

and/or, in the step (2), the operation of the heat treatment is carried out under an inert atmosphere; the inert gas is one or more of helium, argon and hydrogen;

and/or, in the step (2), the temperature of the heat treatment is 300-600 ℃, preferably 500 ℃;

and/or in the step (2), the time of the heat treatment is 1-3h, preferably 2 h;

and/or, in the step (2), the temperature rising rate of the temperature rising to the heat treatment is 1-10 ℃/min, preferably 5 ℃/min;

and/or, in the step (2), after the heat treatment, no acid washing or secondary heat treatment operation is required.

9. The method for preparing a fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst according to any of claims 1-8, characterized by comprising the steps of:

(1) firstly, 0.1 g-0.5 g of palladium chloride and 20-50 ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) adding 0.1-0.5 g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.2-1.0 g of ammonium fluorohydride and 40ml of ethylene glycol into the beaker, stirring vigorously for 2 hours, and then carrying out magnetic stirring at 110 ℃ in a hydrothermal process;

(3) diluting and filtering the solution in deionized water, and drying for 2-5 hours at 80 ℃;

(4) the sample is heated for 2 hours at 500 ℃ in a tube furnace under the mixed atmosphere of hydrogen and argon to obtain the final sample.

10. A fuel cell cathode multi-metal doped multi-metal oxygen reduction catalyst, characterized by being prepared according to the method of any one of claims 1 to 8.

Technical Field

The invention relates to a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst and a preparation method thereof.

Background

A fuel cell is a chemical device that directly converts chemical energy of a fuel into electrical energy, and has advantages of high energy conversion efficiency, wide fuel selection range, cleanliness, less pollution, low noise, high specific energy, strong reliability, fast load response, and ultra-strong applicability, and the like, and a Polymer Electrolyte Fuel Cell (PEFC) is also receiving increasing attention as one of the representatives of the fuel cell.

The catalysts used in PEFC are mainly Pt-based catalysts, and Pt as a rare metal greatly increases the cost of PEFC catalysts. Therefore, the major work in advancing the commercial application of PEFC has focused on reducing Pt loading and increasing the catalytic activity of Pt-based catalysts or seeking other metal, non-metal doping to replace Pt. Although the catalytic activity of the fuel cell catalyst using only the single metal Pd is not as high as that of the Pt catalyst, the catalytic activity of the fuel cell catalyst can be well improved and the cost of the fuel cell catalyst can be reduced to a certain extent by doping metal and nonmetal.

Disclosure of Invention

The invention aims to provide a preparation method of a fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst.

It is yet another object of the present invention to provide: the fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst product prepared by the method is provided.

The purpose of the invention is realized by the following scheme: a preparation method of a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is characterized by comprising the following steps:

(1) preparing a mixed solution of graphene oxide and palladium chloride according to the mass ratio of 1 (0.005-0.0625), and uniformly mixing the mixed solution with N, F-containing nonmetal salt or N, F-containing organic matter and transition metal salt to obtain a dispersion liquid; wherein the volume ratio of the graphene oxide solution to the solvent of the mixed solution is 1 (2-3); the mass ratio of the graphene oxide to the nonmetal salt containing N, F or the organic matter containing N, F to the nonmetal elements is 1 (1: 0.01-0.125); the mole ratio of the nonmetal element of the nonmetal salt containing N, F or the organic matter containing N, F to the metal in the transition metal salt is 1 (0.01-10)

(2) And carrying out suction filtration and separation on the dispersion liquid to obtain a solid, and drying and carrying out heat treatment on the solid.

In the step (1), the graphene oxide can be solid particles or solution;

and/or in the step (1), the solvent in the mixed solution is glycol solvent;

and/or, in the step (1), the concentration of the graphene oxide in the mixed solution is 0.3-0.6 mg/mL;

and/or, in the step (1), the mixed solution is prepared by the following steps: fully stirring and mixing by magnetic stirring, and then carrying out ultrasonic dispersion on the mixed solution to be uniform under the ultrasonic condition.

In the step (1), the graphene oxide is a solution which is subjected to stirring dialysis in deionized water through a biological semipermeable membrane;

and/or in the step (1), the solvent in the mixed solution is glycol;

and/or, in the step (1), the concentration of the carbon nano tube in the mixed solution is 0.4 mg/mL;

and/or, in the step (1), wherein the magnetic stirring time is 2-4 hours;

and/or, in the step (1), the time of ultrasonic dispersion is 20-40 min.

In the step (1), the N, F-containing nonmetal salt or N, F-containing organic matter and transition metal salt are added according to the following steps: under the condition of magnetic stirring, the N, F-containing nonmetal salt or N, F-containing organic matter and transition metal salt are dropwise added into the mixed solution, and the mixed solution is fully stirred by magnetic force and then ultrasonically dispersed until the mixed solution is uniform;

and/or in the step (1), the transition metal salt is cobalt salt, iron salt or nickel salt;

and/or, in the step (1), the transition metal salt exists in the form of nitrate or hydrochloride.

The magnetic stirring time is 2-4 hours, preferably 3 hours;

and/or, in the step (1), the time of ultrasonic dispersion is 20-40min, preferably 30 min;

and/or in the step (1), the transition metal salt is one or more of cobalt nitrate, ferrous nitrate, cobalt nitrate and nickel chloride;

and/or in the step (1), the N, F-containing nonmetal salt or N, F-containing organic matter is one or more of ammonium bifluoride, urea, pyridine, ammonia water and hydrofluoric acid;

in the step (1), the volume ratio of the graphene oxide solution to the solvent of the mixed solution is 1: 2-3; and/or in the step (1), the mass ratio of the graphene oxide to the palladium chloride is 1 (0.005-0.0625);

and/or in the step (1), the mass ratio of the non-metallic elements of the graphene oxide and the non-metallic salt containing N, F or the organic matter containing N, F is 1 (1: 0.01-0.125);

and/or in the step (1), the molar ratio of the nonmetal elements of the N, F-containing nonmetal salt or N, F-containing organic substance to the metal in the transition metal salt is 1 (0.01-10);

in the step (1), the mixing reaction time is 6-14h, preferably 8-12h, for example 10 h;

and/or, in the step (2), the operation of the heat treatment is carried out under an inert atmosphere; the inert gas is one or more of helium, argon and hydrogen;

and/or, in the step (2), the temperature of the heat treatment is 300-600 ℃, preferably 500 ℃;

and/or in the step (2), the time of the heat treatment is 1-3h, preferably 2 h;

and/or, in the step (2), the temperature rising rate of the temperature rising to the heat treatment is 1-10 ℃/min, preferably 5 ℃/min;

and/or, in the step (2), after the heat treatment, no acid washing or secondary heat treatment operation is required.

A preparation method of a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is characterized by comprising the following steps:

(1) firstly, 0.1 g-0.5 g of palladium chloride and 20-50 ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) adding 0.1-0.5 g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.2-1.0 g of ammonium fluorohydride and 40ml of ethylene glycol into the beaker, stirring vigorously for 2 hours, and then carrying out magnetic stirring at 110 ℃ in a hydrothermal process;

(3) diluting and filtering the solution in deionized water, and drying for 2-5 hours at 80 ℃;

(4) the sample is heated for 2 hours at 500 ℃ in a tube furnace under the mixed atmosphere of hydrogen and argon to obtain the final sample.

The invention provides a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst, which is prepared by any one of the methods.

The composite doped carbon carrier of the polymetallic N, F has the advantages of enhancing the conductivity and the specific surface area, and being beneficial to promoting the electron transfer process in the oxygen reduction reaction process; the operation is simple, the prepared oxygen reduction catalyst has a high half-wave potential value, and the activity of the catalyst is high. By using a simple method and taking Pd as a substrate, transition metal and nonmetal elements are reasonably doped by utilizing a synergistic effect, so that certain catalytic activity is improved, certain cost is reduced, and the stability of the cathode catalyst is improved to a certain extent.

Drawings

FIG. 1 is an SEM image of a fuel cell cathode multi-metal doped multi-nonmetal oxygen reduction catalyst of the present invention.

Detailed Description

Example 1:

a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is prepared by the following steps:

(1) firstly, 0.1g of palladium chloride and 20ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) then 0.1g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.2g of ammonium fluorohydride and 40ml of ethylene glycol are added into the beaker, and after vigorous stirring is carried out for 2 hours, magnetic stirring is carried out at the hydrothermal temperature of 110 ℃;

(3) carrying out suction filtration on the dispersion liquid to obtain a solid, and drying the solid for 3 hours at the temperature of 80 ℃;

(4) and heating the sample in a tubular furnace at 500 ℃ for 2h under a hydrogen-argon mixed atmosphere, and carrying out heat treatment to obtain the multi-metal doped multi-element non-metal oxygen reduction catalyst.

Example 2:

a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is similar to the embodiment 1 and is prepared by the following steps:

(1) firstly, 0.5g of palladium chloride and 40ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) then 0.5g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.3g of ammonium fluorohydride and 40ml of ethylene glycol are added into the beaker, and after vigorous stirring is carried out for 2 hours, magnetic stirring is carried out at the hydrothermal temperature of 110 ℃;

(3) diluting and filtering the solution in deionized water, and drying the solution for 3 hours at 80 ℃;

(4) the sample is heated for 2 hours at 500 ℃ in a tube furnace under the mixed atmosphere of hydrogen and argon to obtain the final sample.

Example 3:

a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is similar to the embodiment 1 and is prepared by the following steps:

(1) firstly, 0.3g of palladium chloride and 40ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) then 0.3g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.6g of ammonium fluorohydride and 40ml of ethylene glycol are added into the beaker, and after vigorous stirring is carried out for 2 hours, magnetic stirring is carried out at the hydrothermal temperature of 110 ℃;

(3) diluting and filtering the solution in deionized water, and drying the solution for 3 hours at 80 ℃;

(4) the sample is heated for 2 hours at 500 ℃ in a tube furnace under the mixed atmosphere of hydrogen and argon to obtain the final sample.

Example 4:

a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst is similar to the embodiment 1 and is prepared by the following steps:

(1) firstly, 0.15g of palladium chloride and 40ml (0.4 g/ml) of filtered graphene oxide are weighed and placed in the same beaker, and stirred for 30min at room temperature;

(2) then 0.15g of nickel chloride hexahydrate, ferric chloride, cobalt nitrate hexahydrate, 0.3g of ammonium fluorohydride and 40ml of ethylene glycol are added into the beaker, and after vigorous stirring is carried out for 2 hours, magnetic stirring is carried out at 110 ℃ of hydrothermal reaction;

(3) diluting and filtering the solution in deionized water, and drying the solution for 3 hours at 80 ℃;

(4) the sample is heated for 2 hours at 500 ℃ in a tube furnace under the mixed atmosphere of hydrogen and argon to obtain the final sample.

FIG. 1 is an SEM image of a fuel cell cathode multi-metal doped multi-element non-metal oxygen reduction catalyst synthesized by the invention, and it can be seen from the SEM image that the obtained sample is a nano-sheet self-assembled hierarchical structure, the thickness of the nano-sheet is about 1-5 nm, the diameter of the nano-sheet is 1-50 nm, and the nano-sheets are mutually cross-assembled.