CN106910899B - A kind of preparation method of nitrogen-doped double-shell structure nanocatalyst - Google Patents

Abstract

The invention discloses a preparation method of a nitrogen-doped double-shell structure nano catalyst, which comprises the following operation steps: (1) adding a carrier and a metal precursor into a solvent, stirring, adding a reducing agent for reduction, filtering, cleaning and drying to obtain a primary product; (2) placing the mixture in a high-temperature reaction furnace, introducing gas and calcining to obtain a nitrogen-doped nano alloy catalyst; (3) and performing dealloying treatment to obtain the nitrogen-doped double-shell structure nano catalyst. The catalyst has 5-19 times of activity of commercial 20 wt% Pt/C catalyst in oxygen reduction mass at 0.9V, has higher oxygen reduction catalytic performance, and lays a technical foundation for large-scale application of proton exchange membrane fuel cells.

Description

A kind of preparation method of nitrogen-doped double-shell structure nanocatalyst

technical field

The invention relates to a preparation method of a nano-catalyst, in particular to a preparation method of a nitrogen-doped double-shell structure nano-catalyst.

Background technique

At present, with the continuous growth of energy demand and the continuous enhancement of environmental protection awareness, the development of clean energy conversion technology is urgently needed. Proton exchange membrane fuel cells offer a promising pathway for clean energy conversion, but their commercialization suffers from high cost and poor stability. Platinum is an efficient catalyst for proton exchange membrane fuel cells. However, due to its extremely low content in the earth's crust and its growing demand in the automotive industry, researchers are working to develop high-efficiency non-precious metal catalysts and low-content precious metal catalysts.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention invents a method for preparing a nitrogen-doped double-shell structure nanocatalyst, aiming to obtain a nitrogen-doped double-shell structure nanocatalyst with simple process, low cost and good catalytic performance.

For achieving the above object, the technical scheme provided by the invention is as follows:

A method for preparing a nitrogen-doped double-shell structure nanocatalyst, comprising the following operation steps:

(1) reduction of the catalyst: add the carrier and the metal precursor into the solvent, then ultrasonically stir, add a reducing agent, heat and reduce, filter, wash and dry the mixture obtained from the reduction to obtain a primary product;

(2) high-temperature calcination of catalyst: the primary product obtained in step (1) is placed in a high-temperature reaction furnace, and the temperature of the high-temperature reaction furnace can be controlled by a program, and gas is introduced for high-temperature calcination to obtain a nitrogen-doped nano-alloy catalyst;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is subjected to deal-alloying treatment to obtain a nano-catalyst with a nitrogen-doped double-shell structure.

Wherein, the carrier described in the step (1) is any one or more of carbon black, carbon nanotubes, carbon fibers, carbon nanorods, graphene, graphene oxide, reduced graphene oxide, activated carbon, and porous carbon. combination; the solvent is any one or a combination of deionized water, ethanol, isopropanol, and ethylene glycol.

Wherein, the metal precursors described in step (1) are composed of class I and class II metal precursors, the class I is platinum salt and/or palladium salt, and class II is iron salt, cobalt salt, nickel salt , tungsten salt, molybdenum salt or vanadium salt in one or two mixtures.

Wherein, the combinations of the metal precursors include: platinum iron tungsten, platinum iron molybdenum, platinum iron vanadium, platinum cobalt tungsten, platinum cobalt molybdenum, platinum cobalt vanadium, platinum nickel tungsten, platinum nickel molybdenum, platinum nickel vanadium, palladium iron tungsten , palladium iron molybdenum, palladium iron vanadium, palladium cobalt tungsten, palladium cobalt molybdenum, palladium cobalt vanadium, palladium nickel tungsten, palladium nickel molybdenum, palladium nickel vanadium, platinum iron cobalt, platinum iron nickel, platinum cobalt nickel, platinum tungsten molybdenum, platinum Tungsten vanadium, platinum molybdenum vanadium, palladium iron cobalt, palladium iron nickel, palladium cobalt nickel, palladium tungsten molybdenum, palladium tungsten vanadium, palladium molybdenum vanadium, platinum palladium iron, platinum palladium cobalt, platinum palladium nickel, platinum palladium tungsten, platinum palladium molybdenum , platinum palladium vanadium; the molar ratio between the three elements in the combination is 1-10:1-20:1-20.

Wherein, the platinum salt is chloroplatinic acid, platinum acetylacetonate, ammonium hexachloroplatinate, potassium hexachloroplatinate, sodium hexachloroplatinate, potassium tetrachloroplatinate, sodium chloroplatinite, platinum tetrachloride , platinum nitrate, tetraammine platinum nitrate, tetraammine platinum chloride; Described palladium salt is palladium chloride, palladium acetate, ammonium chloropalladite, potassium chloropalladate, palladium sulfate, palladium nitrate, tetrachloride Sodium palladate, potassium tetrachloropalladate, potassium tetrabromopalladate, palladium dibromide, palladium trifluoroacetate, palladium acetylacetonate, palladium dichlorodiamine, palladium tetraamino nitrate, palladium hexafluoroacetylacetonate, triphenyl Phosphine palladium acetate, tetrakis(triphenylphosphine) palladium, bis(benzonitrile) palladium dichloride, bis(triphenylphosphine) palladium chloride, tris(benzylideneacetone)dipalladium, bis(dibenzylidene) Acetone) palladium, tris(dibenzylideneacetone)dipalladium, (1,5-cyclooctadiene)palladium dichloride, (1,3-bis(diphenylphosphine)propane)palladium chloride, 1, 2-bis(diphenylphosphino)ethane palladium dichloride; Described iron salt is ferric chloride, ferrous chloride, ferric acetylacetonate, potassium ferricyanide, sodium ferrocyanide, nitrous Sodium ferrocyanide, ferrocene, ferric nitrate, ferric citrate, ferric ammonium citrate, ferric ammonium oxalate, ferrous oxalate, potassium hexacyanoferrate, ferric sulfate, ferrous sulfate, ferrous ammonium sulfate, Ferric ammonium sulfate; the cobalt salts are cobalt chloride, cobalt acetate, cobalt phosphate, cobalt phthalocyanine, potassium cobalt cyanide, potassium hexacyanocobaltate, hexaamino cobalt chloride, cobalt perchlorate, cobalt nitrate, fluorine Cobalt oxide, cobalt iodide, cobalt bromide, sodium cobalt nitrite, cobalt oxalate, cobalt sulfate, cobaltous sulfate, cobalt ammonium sulfate, cobalt naphthenate, cobalt acetylacetonate; Nickel acetone, nickel acetylacetonate, nickel acetate, nickel bromide, nickel iodide, nickel sulfate, nickel nitrate, nickel ammonium sulfate, nickel hypophosphite, nickel ammonium nitrate, nickel sulfamate, basic nickel carbonate, nickel formate, Nickellocene, bis(triphenylphosphine) nickel bromide, bis(triphenylphosphine) nickel chloride; the tungsten salts are ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium tungstate, phosphorus Tungstic acid, sodium phosphotungstate, tungstosilicic acid, tungsten hexachloride, tungsten hexacarbonyl, tungsten isopropoxide; the molybdenum salts are molybdic acid, ammonium tetramolybdate, ammonium heptamolybdate, ammonium dimolybdate, Sodium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdate, molybdenum hexacarbonyl, molybdenum acetylacetonate, molybdenum isopropoxide; described vanadium salt is partial Ammonium vanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium oxide, vanadium tetrachloride, sodium vanadate, vanadium acetylacetonate, vanadyl triisopropoxide, vanadyl acetylacetonate , triisopropoxy vanadium oxide, vanadium oxide diacetylacetonate.

Wherein, the mass ratio of the carrier described in step (1) to the metal contained in the metal precursor is 0.25-99:1.

Wherein, the temperature of the heating reduction described in the step (1) is 40～200 degrees Celsius, and the reduction time is 0.1～100 hours; the heating mode is water bath heating, oil bath heating, sand bath heating or high temperature reaction kettle. any kind.

Wherein, the reducing agent described in step (1) is any one or a combination of several in sodium borohydride, potassium borohydride, hydrazine hydrate, formic acid, acetic acid; Described drying is under vacuum or inert gas protection Heating to 50-120 degrees Celsius and drying for 12 hours; the inert gas is any one or a combination of nitrogen, helium and argon.

Wherein, the high-temperature calcination procedure described in step (2) is divided into two steps: the first step is to introduce reducing gas at 20～350 degrees Celsius, the calcination temperature is 250～350 degrees Celsius, and the calcination time is 0.1～10 hours; The second step is to introduce a mixture of ammonia gas and inert gas at 350 to 1000 degrees Celsius, the calcination temperature is 500 to 1000 degrees Celsius, the calcination time is 0.1 to 10 hours, and the proportion of ammonia in the mixture is arbitrary and not zero; The reducing gas is a mixture of hydrogen and an inert gas, wherein the proportion of hydrogen is arbitrary and not zero; the inert gas is any one or a combination of nitrogen, helium, and argon.

Wherein, the dealloying described in step (3) is realized by means of electrochemistry and pickling.

Compared with the prior art, the present invention has the following beneficial effects:

The technical scheme of the present invention realizes the regulation of the nitrogen content in the catalyst and the control of the thickness of the shell layer by adjusting the ratio of the metal precursor and the high-temperature calcination process. The obtained catalyst has a uniform morphology, good catalytic activity and electrochemical stability, and can be greatly Reduce the cost of proton exchange membrane fuel cells. In 0.1 mol/L saturated oxygen perchloric acid solution, the oxygen reduction mass activity of the catalyst of the present invention at 0.9 V is 5-19 times that of the commercial 20wt% Pt/C catalyst, and the catalyst prepared by this method has higher oxygen reduction The catalytic performance has laid a technical foundation for the large-scale application of proton exchange membrane fuel cells.

Description of drawings

Fig. 1 is the process flow diagram of the preparation method of the present invention.

2 is an X-ray diffraction diagram of the platinum-iron-molybdenum system catalyst prepared in Example 1, Example 2, and Example 3 of the present invention.

Figure 3 shows the oxygen reduction of the platinum-iron-molybdenum system catalyst and commercial 20wt% Pt/C catalyst prepared in Example 1, Example 2, and Example 3 of the present invention at 0.9 volts in a 0.1 mol/L saturated oxygen perchloric acid solution Comparison chart of mass activity.

Detailed ways

The following will describe in detail the specific embodiments in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Example 1

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) reduction of catalyst: take 2 ml of chloroplatinic acid aqueous solution with a concentration of 42 mg/ml, dissolve 19 mg of ferric chloride and 12 mg of ammonium heptamolybdate in 50 ml of deionized water, and obtain metal precursors solution, then add 200 mg of carbon black to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a constant temperature oil bath at 50 degrees Celsius with magnetic stirring, and then add 27 mg of sodium borohydride for reduction for 24 hours , filtered and washed with deionized water, and the obtained filter residue was vacuum-dried at 60 degrees Celsius for 12 hours to obtain solid powder, which was the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 300 degrees Celsius at a rate of 5 degrees Celsius per minute, then keep calcined for 1 hour; then feed ammonia gas, heat from 300 degrees Celsius to 600 degrees Celsius at a speed of 5 degrees Celsius per minute, then keep calcined for 1 hour, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 4 hours, and then the filtration, cleaning and drying steps in step (1) are: MoN@Fe ₁ @Pt ₃ /C nanocatalysts with nitrogen-doped double-shell structure were obtained.

Example 2

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) Reduction of catalyst: take 1.7 ml of chloroplatinic acid aqueous solution with a concentration of 42 mg/ml, 48 mg of ferric chloride and 11 mg of ammonium heptamolybdate and dissolve in 50 ml of deionized water to obtain metal precursors solution, then add 200 mg of carbon black to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a constant temperature oil bath at 50 degrees Celsius with magnetic stirring, and then add 32 mg of sodium borohydride for reduction for 24 hours , filtered and washed with deionized water, and the obtained filter residue was vacuum-dried at 60 degrees Celsius for 12 hours to obtain solid powder, which was the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 300 degrees Celsius at a rate of 5 degrees Celsius per minute, then keep calcined for 1 hour; then feed ammonia gas, heat from 300 degrees Celsius to 600 degrees Celsius at a speed of 5 degrees Celsius per minute, then keep calcined for 1 hour, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 4 hours, and then the filtration, cleaning and drying steps in step (1) are: MoN@Fe ₃ @Pt ₃ /C nanocatalysts with nitrogen-doped double-shell structure were obtained.

Example 3

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) reduction of catalyst: take 1.5 ml of chloroplatinic acid aqueous solution with a concentration of 42 mg/ml, 71 mg of ferric chloride and 9 mg of ammonium heptamolybdate and dissolve in 50 ml of deionized water to obtain metal precursors solution, then add 200 mg of carbon black to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a constant temperature oil bath at 50 degrees Celsius with magnetic stirring, and then add 37 mg of sodium borohydride for reduction for 24 hours , filtered and washed with deionized water, and the obtained filter residue was vacuum-dried at 60 degrees Celsius for 12 hours to obtain solid powder, which was the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 300 degrees Celsius at a rate of 5 degrees Celsius per minute, then keep calcined for 1 hour; then feed ammonia gas, heat from 300 degrees Celsius to 600 degrees Celsius at a speed of 5 degrees Celsius per minute, then keep calcined for 1 hour, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 4 hours, and then the filtration, cleaning and drying steps in step (1) are: MoN@Fe ₅ @Pt ₃ /C nanocatalysts with nitrogen-doped double-shell structure were obtained.

Example 4

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) reduction of catalyst: take 16.4 ml of platinum tetrachloride aqueous solution with a concentration of 20 mg/ml, dissolve 23 mg of cobalt chloride and 11 mg of ammonium metavanadate in 50 ml of deionized water to obtain a metal precursor solution, then add 50 mg of graphene oxide to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a constant temperature water bath at 40 degrees Celsius with magnetic stirring, and then add 131 mg of potassium borohydride for reduction for 100 hours , filtered and washed with deionized water, and the obtained filter residue was vacuum-dried at 80 degrees Celsius for 12 hours to obtain solid powder, which was the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 250 degrees Celsius at a speed of 5 degrees Celsius per minute, and then keep calcined for 10 hours; then feed ammonia gas, heat from 250 degrees Celsius to 500 degrees Celsius at a speed of 5 degrees Celsius per minute, then keep calcined for 10 hours, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 6 hours, and then the filtration, cleaning and drying steps in step (1) are: The VN@Co ₁ @Pt ₁₀ /Graphene nanocatalyst with nitrogen-doped double-shell structure was obtained.

Example 5

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) reduction of catalyst: take 0.8 ml of palladium chloride aqueous solution with a concentration of 2.5 mg/ml, dissolve 63 mg of ferric chloride and 20 mg of ammonium heptamolybdate in 50 ml of deionized water to obtain metal precursors solution, then add 225 mg of carbon nanotubes to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a constant temperature sand bath at 200 degrees Celsius with magnetic stirring, and then add 40 mg of potassium borohydride to reduce 0.1 hour, filter and wash with deionized water, and the obtained filter residue is vacuum-dried at 120 degrees Celsius for 12 hours to obtain solid powder, which is the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 350 degrees Celsius at a rate of 5 degrees Celsius per minute, and then keep calcined for 0.1 hour; then introduce ammonia gas, heat from 350 degrees Celsius to 1000 degrees Celsius at a speed of 5 degrees Celsius per minute, then keep calcined for 0.1 hour, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 12 hours, and then the filtration, cleaning and drying steps in step (1) are: MoN@Fe ₂₀ @Pd ₁ /CNTs nanocatalysts with nitrogen-doped double-shell structure were obtained.

Example 6

A preparation method of a nitrogen-doped double-shell structure nanocatalyst, the operation steps are as follows:

(1) reduction of catalyst: take 1.3 ml of palladium sulfate aqueous solution with a concentration of 2.5 mg/ml, dissolve 7 mg of nickel acetate and 15 mg of ammonium tungstate in 50 ml of deionized water to obtain a metal precursor solution, and then add it to Add 237 mg of activated carbon to the metal precursor solution, ultrasonically stir and disperse to obtain a suspension, then move it to a water bath at 90 degrees Celsius with magnetic stirring, then add 6 mg of sodium borohydride to reduce for 2 hours, filter and rinse with deionized water , the obtained filter residue is vacuum-dried at 50 degrees Celsius for 12 hours to obtain solid powder, which is the primary product;

(2) High-temperature calcination of the catalyst: the primary product obtained in step (1) is placed in a crucible, placed in a high-temperature reaction tube furnace, and a hydrogen/argon mixed gas with a hydrogen volume fraction of 5% is introduced first, with each Heat from room temperature to 300 degrees Celsius at a rate of 5 degrees Celsius per minute, then keep calcined for 1 hour; then feed ammonia gas, heat from 300 degrees Celsius to 800 degrees Celsius at a rate of 5 degrees Celsius per minute, then keep calcined for 5 hours, and naturally cool to room temperature, A nitrogen-doped nano-alloy catalyst is obtained;

(3) dealloying treatment: the nitrogen-doped nano-alloy catalyst obtained in step (2) is placed in a 0.5 mol/L sulfuric acid solution and stirred for 24 hours, and then the filtration, cleaning and drying steps in step (1) are: A nitrogen-doped double-shell structure W ₂₀ N@Ni ₁ @Pd ₁ /activated carbon nanocatalyst was obtained.

Electrochemical performance test of the obtained nitrogen-doped double-shell nanocatalyst:

(1) Weigh 5 mg of catalysts prepared in Examples 1 to 3 of the present invention and 5 mg of commercial 20wt% Pt/C catalysts, respectively, and put them into 1 ml of Nafion solution, which was purchased from 20 microliters of Nafion solution. It was prepared by mixing 5wt% Nafion solution of DuPont and 980 μl ethanol, ultrasonicated for 15 minutes, and then used a sampler to take 10 μl of slurry droplets on the rotating disk electrode. After drying, use the PINE electrochemical workstation to carry out Electrochemical testing.

(2) The test conditions are as follows: the carbon rod is used as the counter electrode, the silver/silver chloride electrode is used as the reference electrode, and the disc electrode is used as the working electrode to form a three-electrode test system. liquid.

2 is an X-ray diffraction diagram of the platinum-iron-molybdenum system catalyst prepared in Examples 1 to 3 of the present invention.

Figure 3 is a comparison chart of the oxygen reduction mass activity of the platinum-iron-molybdenum system catalyst prepared in Examples 1 to 3 of the present invention and a commercial 20wt% Pt/C catalyst at 0.9 volts; from Figure 3, we can see that this The catalyst prepared by the invention has excellent oxygen reduction catalytic activity. In a 0.1 mol/liter saturated oxygen perchloric acid solution, the oxygen reduction mass activity of the catalyst of the invention at 0.9 volts is 5-19 times that of a commercial 20wt% Pt/C catalyst. , which can greatly reduce the cost of proton exchange membrane fuel cells.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many changes and modifications are possible in light of the above teachings. The exemplary embodiments were chosen and described for the purpose of explaining certain principles of the invention and their practical applications, to thereby enable one skilled in the art to make and utilize various exemplary embodiments and various different aspects of the invention. Choose and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims (6)

1. A preparation method of a nitrogen-doped double-shell structure nano catalyst is characterized by comprising the following operation steps:

(1) and (3) reduction of the catalyst: adding a carrier and a metal precursor into a solvent, stirring, adding a reducing agent, heating to 40-200 ℃, reducing for 0.1-100 hours, filtering, cleaning and drying a mixture obtained by reduction to obtain a primary product; the carrier is any one or combination of a plurality of carbon black, carbon nano tubes, carbon fibers, carbon nano rods, graphene oxide, reduced graphene oxide, activated carbon and porous carbon; wherein, the metal precursor combination mode comprises the following steps: platinum iron tungsten, platinum iron molybdenum, platinum iron vanadium, platinum cobalt tungsten, platinum cobalt molybdenum, platinum cobalt vanadium, platinum nickel tungsten, platinum nickel molybdenum, platinum nickel vanadium, palladium iron tungsten, palladium iron molybdenum, palladium iron vanadium, palladium cobalt tungsten, palladium cobalt molybdenum, palladium cobalt vanadium, palladium nickel tungsten, palladium nickel molybdenum, palladium nickel vanadium, platinum iron cobalt, platinum iron nickel, platinum cobalt nickel, platinum tungsten molybdenum, platinum tungsten vanadium, platinum molybdenum vanadium, palladium iron cobalt, palladium iron nickel, palladium cobalt nickel, palladium tungsten molybdenum, palladium tungsten vanadium, palladium molybdenum vanadium, platinum palladium iron, platinum palladium cobalt, platinum palladium nickel, platinum palladium tungsten, platinum palladium molybdenum or platinum palladium vanadium; the molar ratio of the three elements in the combination is 1-10: 1-20; the platinum is a platinum salt, and the platinum salt is acetylacetone platinum, ammonium hexachloroplatinate, potassium hexachloroplatinate, sodium hexachloroplatinate, potassium tetrachloroplatinate, sodium chloroplatinate, platinum tetrachloride, platinum nitrate, platinum tetraammine nitrate or platinum tetraammine chloride; the palladium is a palladium salt which is palladium chloride, palladium acetate, ammonium chloropalladite, potassium chloropalladite, palladium sulfate, palladium nitrate, sodium tetrachloropalladate, potassium tetrabromopaalladite, palladium dibromide, palladium trifluoroacetate, palladium acetylacetonate, dichlorodiammine palladium, tetraaminopalladium nitrate, palladium hexafluoroacetylacetonate, palladium triphenylphosphine acetate, tetrakis (triphenylphosphine) palladium, bis (benzonitrile) palladium dichloride, bis (triphenylphosphine) palladium chloride, tris (benzylideneacetone) dipalladium, bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, (1, 5-cyclooctadiene) palladium dichloride, (1, 3-bis (diphenylphosphino) propane) palladium chloride or 1, 2-bis (diphenylphosphino) ethane palladium dichloride; the iron is ferric salt, and the ferric salt is ferric chloride, ferrous chloride, ferric acetylacetonate, potassium ferricyanide, sodium ferrocyanide, sodium nitrosoferrocyanide, ferrocene, ferric nitrate, ferric citrate, ferric ammonium oxalate, ferrous oxalate, potassium hexacyanoferrate, ferric sulfate, ferrous ammonium sulfate or ferric ammonium sulfate; the cobalt is a cobalt salt, and the cobalt salt is cobalt chloride, cobalt acetate, cobalt phosphate, cobalt phthalocyanine, potassium cobalt cyanide, potassium hexacyanocobaltate, hexaaminocobalt chloride, cobalt perchlorate, cobalt nitrate, cobalt fluoride, cobalt iodide, cobalt bromide, cobalt sodium nitrite, cobalt oxalate, cobalt sulfate, cobaltous sulfate, cobalt ammonium sulfate, cobalt naphthenate or cobalt acetylacetonate; the nickel is nickel salt, and the nickel salt is nickel chloride, nickel acetylacetonate, nickel acetate, nickel bromide, nickel iodide, nickel sulfate, nickel nitrate, nickel ammonium sulfate, nickel hypophosphite, nickel ammonium nitrate, nickel sulfamate, basic nickel carbonate, nickel formate, nickelocene, bis (triphenylphosphine) nickel bromide or bis (triphenylphosphine) nickel chloride; the tungsten is tungsten salt, and the tungsten salt is ammonium metatungstate, ammonium tungstate, potassium tungstate, sodium phosphotungstate, tungsten hexachloride, tungsten hexacarbonyl and tungsten isopropoxide; the molybdenum is molybdenum salt, and the molybdenum salt is ammonium tetramolybdate, ammonium heptamolybdate, ammonium dimolybdate, sodium molybdate, ammonium phosphomolybdate, sodium phosphomolybdate, molybdenum chloride, lithium molybdate, potassium molybdate, molybdenum hexacarbonyl, molybdenum acetylacetonate or molybdenum isopropoxide; the vanadium is a vanadium salt, and the vanadium salt is ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadium chloride, vanadium tetrachloride, sodium vanadate, vanadium acetylacetonate, triisopropoxvanadyl, vanadyl acetylacetonate, triisopropoxytriantioxide or vanadyl diacetoneate oxide;

(2) high-temperature calcination of the catalyst: placing the primary product obtained in the step (1) in a high-temperature reaction furnace, and introducing gas for high-temperature calcination to obtain a nitrogen-doped nano alloy catalyst;

the high-temperature calcination procedure is divided into two steps: the first step is that reducing gas is introduced at the temperature of 20-350 ℃, the calcining temperature is 250-350 ℃, and the calcining time is 0.1-10 hours; secondly, introducing a mixed gas of ammonia and inert gas at 350-1000 ℃, wherein the calcining temperature is 500-1000 ℃, the calcining time is 0.1-10 hours, and the proportion of the ammonia in the mixed gas is arbitrary and is not zero; the reducing gas is a mixed gas of hydrogen and inert gas, wherein the proportion of the hydrogen is arbitrary and is not zero; the inert gas is any one or combination of several of nitrogen, helium and argon;

(3) dealloying treatment: and (3) carrying out dealloying treatment on the nitrogen-doped nano alloy catalyst obtained in the step (2) to obtain the nitrogen-doped nano catalyst with a double-shell structure.

2. The method of claim 1, wherein: the solvent in the step (1) is any one or a combination of several of deionized water, ethanol, isopropanol and ethylene glycol.

3. The method of claim 1, wherein: the mass ratio of the carrier in the step (1) to the metal contained in the metal precursor is 0.25-99: 1.

4. The method of claim 1, wherein: the heating mode in the step (1) is any one of water bath heating, oil bath heating, sand bath heating or high-temperature reaction kettle heating.

5. The method of claim 1, wherein: the reducing agent in the step (1) is any one or a combination of several of sodium borohydride, potassium borohydride, hydrazine hydrate, formic acid and acetic acid; the drying is carried out by heating to 50-120 ℃ under vacuum or inert gas protection for 12 hours; the inert gas is any one or combination of several of nitrogen, helium and argon.

6. The method of claim 1, wherein: the dealloying in the step (3) is realized by means of electrochemistry and acid washing.

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