CN117691125A

CN117691125A - Carbon carrier material, preparation method, electrocatalyst and application

Info

Publication number: CN117691125A
Application number: CN202311742878.8A
Authority: CN
Inventors: 陈首先; 周卫江; 鲜佳玲; 王正罗; 陈甜; 舒正龙; 陈启章
Original assignee: Sinocat Environmental Technology Co Ltd
Current assignee: Sinocat Environmental Technology Co Ltd
Priority date: 2023-12-18
Filing date: 2023-12-18
Publication date: 2024-03-12

Abstract

The invention relates to the technical field of modification of nano carrier materials and electrocatalysis, in particular to a carbon carrier material, a preparation method, an electrocatalyst and application. On the premise of not influencing the conductivity of the carrier material, the method greatly reduces the micropore number and pore volume of the carbon material by filling the transition metal oxide into the pores of the carbon carrier, thereby improving the dispersity and the utilization rate of noble metals such as platinum and the like loaded on the surface of the carrier, simultaneously, part of noble metal nano particles are positioned at the interface position of the transition metal oxide and the carbon material, and the stability of the noble metal particles and the electrocatalyst is improved by utilizing the strong interaction between the oxide and the noble metal particles. The platinum-based electrocatalyst prepared by using the carbon carrier has the advantages of good stability, high conductivity, high catalytic activity and the like.

Description

Carbon carrier material, preparation method, electrocatalyst and application

Technical Field

The invention belongs to the technical field of modification of nano carrier materials and electrocatalysis, and particularly relates to an electrode catalyst carrier or other electrode materials used for fuel cells, metal-air cells, electrolytic cells and the like. In particular to a carbon carrier material, a preparation method, an electrocatalyst and application.

Background

Along with the increase of environmental awareness and the improvement of living standard, the requirements on environment and living quality are also higher and higher. In order to improve the environment, treat pollution and reduce emission, the use of clean energy sources such as hydrogen energy must be quickened. The hydrogen energy is an extremely important grip for realizing the whole society decarburization and the energy transformation. High-efficiency stable electrocatalysts are required in electrochemical energy devices such as electrolytic tanks and fuel cells required for green hydrogen production and hydrogen electrotransformation.

In various electrochemical energy catalytic reactions, such as oxygen electrochemical reduction reaction, electrolytic water oxygen evolution reaction, electrolytic water hydrogen evolution reaction and the like, the electrocatalyst and the carrier thereof are usually in a strong acidic or alkaline environment and a high potential, and the reaction conditions are severe, so that the electrocatalyst and the carrier thereof are required to have good electrochemical stability, mechanical stability and high conductivity. The nature of the support material is one of the most important factors determining the performance and stability of the electrocatalyst. The requirement of higher conductivity limits the range of materials for electrocatalyst support materials to a certain extent, and currently, supports for noble metal catalysts such as platinum and the like in electrolytic cells or fuel cells are still mainly made of carbon materials. The currently used carbon materials are mainly of two types, namely porous carbon materials with high specific surface area so as to improve the dispersity of noble metals; the other type is a carbon material with higher graphitization degree so as to improve the stability of the carrier material and the electrocatalyst under the high-potential condition. The former type of carbon material generally has more pore structures of 2-10nm, the large specific surface area and the higher pore volume are closely related to the microporous structures, the dispersion degree of the loaded noble metal is higher, but a considerable part of noble metal nano particles can be distributed in the micropores or mesopores, and under the actual electrochemical working environment, the transmission channels of ions and/or other reactants or products are blocked, so that the noble metal nano particles in the pores are not utilized, and the utilization rate of the noble metal is reduced. The surface area of the carbon material with higher graphitization degree is usually smaller, and the surface pore structure is smaller, which is unfavorable for the loading and dispersion of nano particles such as platinum on the surfaces of the carriers. Strategies to improve platinum dispersibility and platinum utilization are: preparing a catalyst with a core-shell structure, improving the structure of a carrier, using a composite carrier and the like. In the existing composite carrier material containing carbon materials and transition metal oxides, the platinum can be better dispersed on the carrier by utilizing the strong interaction between the transition metal oxides and the platinum, and platinum particles can be prevented from falling off, so that the activity and stability of the catalyst are improved. However, the transition metal oxide is usually pre-loaded on the surface of the carbon carrier, and then noble metal particles such as platinum are loaded, so that a considerable amount of noble metal nanoparticles in the structure are inevitably located on the surface of the transition metal oxide particles, and cannot contact with the carbon material, so that an electron transfer channel is broken, and the noble metal particles cannot be fully utilized under the actual electrochemical reaction condition.

Disclosure of Invention

The catalyst carrier materials widely used in electrochemical energy devices such as fuel cells are mainly porous carbon, and the complex and fine pore structure of the catalyst carrier materials can increase the specific surface of the carrier and improve the dispersity of noble metals such as platinum, but is not favorable for the utilization rate of the noble metals, especially under actual working conditions, noble metal nano particles in the pore structures cannot be contacted with electrolyte, or pore channels are blocked and the like to improve the mass transfer resistance, so that the utilization rate of the noble metals is greatly reduced, and a considerable part of noble metals are wasted. The highly graphitized carbon carrier material has a simple surface structure, a small specific surface area and weak interaction between noble metal particles, is unfavorable for the dispersion and adhesion of noble metals, and causes that the activity, stability, noble metal utilization rate and the like of the highly graphitized carbon carrier material are difficult to meet the requirements.

The invention aims at: aiming at the technical problems existing in the prior art, a preparation method of a carbon carrier material is provided.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a method for preparing a carbon support material, comprising the following preparation steps:

step 1, pretreating a carbon carrier material by adopting an oxidizing solution;

Step 2, drying the carbon carrier material;

step 3, adding a carbon carrier material into a solution containing a filler precursor material under the anhydrous and anaerobic condition to form a mixed solution, dispersing and uniformly mixing, and adsorbing the filler precursor solution into micropores of the carbon carrier material through reduced pressure adsorption; the filler precursor material is a transition metal salt;

step 4, carrying out solid-liquid separation and drying treatment on the mixed solution obtained in the step 3 to remove the solvent, so that the filler precursor is fixed in micropores of the carbon carrier material, and sample powder is obtained;

and 5, carrying out high-temperature treatment on the sample powder obtained in the step 4 to obtain the carbon carrier material after the transition metal oxide and/or metal particles are filled.

In the preparation process of the invention, the purpose of the oxidizing solution treatment is as follows: washing out impurities in the carbon carrier material and changing the hydrophilicity and hydrophobicity of the carrier; under the anaerobic and anhydrous conditions, the transition metal precursor is accurately filled into micropores of the carbon carrier, so that the problem that the compounds cannot enter the micropores of the carrier due to advanced hydrolysis and are adsorbed on the outer surface of the carbon carrier to form oxides on the outer surface, and the conductivity and the performance of the carrier and the catalyst are influenced is avoided. The transition metal precursor solution enters the pore canal of the carbon carrier through the full dispersion and the decompression absorption of the carbon carrier in the transition metal precursor solution. The filler precursor is fixed in the micropores of the carbon carrier material by controlling the hydrolysis process and drying; by controlling the heat treatment conditions, the filler in the pores of the carbon carrier can be changed into different oxidation states or reduction states, and a contact interface between the transition metal or the oxide thereof and the carbon carrier is formed, so that the conductivity of the carrier is not affected, and the interaction between the transition metal oxide and the platinum nano particles can be realized.

According to the technical scheme, the transition metal oxide is filled in the pores of the porous carbon carrier material, so that the complex pore structure in the carbon material can be blocked, the number of micropores and pore volume are greatly reduced, and precious metal nanoparticles (for example, about two nanometers) are prevented from falling into micropores and mesopores, so that the utilization rate of precious metal is low, and the subsequently loaded precious metal nanoparticles can be distributed on the outer surface of the carbon carrier material as much as possible, so that the utilization rate of precious metal is improved.

On the other hand, the modification scheme can also form shallow holes on the surface of the carbon carrier, so that partial transition metal oxide is arranged on the surface of the carbon carrier, an interface structure of the transition metal oxide and the carbon material is formed, when the noble metal particles are arranged on the surface of the transition metal oxide, the strong interaction between the transition metal oxide and the noble metal particles can be ensured, the activity and the stability of the noble metal particles are improved, and meanwhile, the noble metal particles are contacted with the carbon material, so that the smoothness of an electronic channel is ensured. Because the transition metal oxide is mainly filled in the pores of the carbon carrier material, but not the outer surface, the structure and the mutual contact capability of the carbon material are not affected, and the electron transmission channel is not isolated or interrupted, the conductivity of the transition metal oxide is not affected basically before and after the oxide is filled, and the electrocatalyst prepared by the carbon carrier material, such as a platinum-based electrocatalyst, has higher electrocatalytic activity, conductivity and durability.

Preferably, in the step 1, the oxidizing solution includes one or more of nitric acid, concentrated sulfuric acid, hydrogen peroxide, perchloric acid and potassium permanganate aqueous solution;

the specific process of pretreatment in the step 1 is as follows:

mixing the carbon carrier material with the oxidizing acid solution, stirring and heating for reflux treatment, wherein the treatment temperature is 50-150 ℃, the treatment time is 0.5-24h, and the stirring speed is 200-1000 rpm; after the reaction is finished, the carbon carrier material after the oxidation treatment is obtained through solid-liquid separation, washing and drying.

More specifically, in step 1, the solid-liquid separation mode includes any one of suction filtration and high-speed centrifugal separation; the drying is preferably freeze-drying.

In step 1, if the impurity and/or ash content in the carbon support material selected is less than 1wt%, the oxidation treatment of the carbon support material may alternatively be performed by heat treatment in an oxidizing atmosphere; the oxidizing atmosphere includes a mixed gas containing oxygen, ozone, and the like; the concentration of the oxidizing atmosphere is further adjusted by controlling the volume ratio of the oxidizing atmosphere to the inert atmosphere.

Preferably, the carbon carrier material comprises carbon black, graphene and a mixture of one or more of graphene oxide, carbon fiber and carbon nano tube. The pore diameter of the carbon carrier material is not more than 30nm, wherein the micropore ratio of the pore diameter below 10nm is more than 50%.

Preferably, in the step 2, the drying temperature is 100-300 ℃ and the drying time is 2-24 hours, so as to remove water, organic matters and the like adsorbed in micropores of the carbon carrier material; after the drying treatment, the water content in the carbon support material is required to be not more than 0.5%, preferably not more than 0.2%. The drying process is carried out in a vacuum oven.

Preferably, in step 3, the filler precursor is formulated as a solution and then added to the carbon support material; the solvent should be able to sufficiently dissolve the selected filler precursor without destroying its chemical structure and composition. The solvent must be an anhydrous organic solvent, and the dissolution process must be operated under anhydrous conditions. The solvent selected for preparing the filler precursor solution comprises one or a mixture of a plurality of volatile low-carbon organic solvents, including any one or a combination of a plurality of methanol, ethanol, propanol, acetone and chloroform.

As a preferable technical scheme of the invention, the filler precursor material is adsorbed into micropores of the carbon carrier material in a decompression adsorption mode, and the volume of the filler precursor solution is 1-10 times of the pore volume of the carbon carrier material; the filler precursor material is a transition metal salt.

Preferably, in step 3, the filler precursor material comprises a transition metal compound; including but not limited to one or a combination of several of titanium salts (e.g., titanium tetrachloride), cerium salts (e.g., cerium nitrate), niobium salts (e.g., niobium chloride, niobium oxalate, etc.), tungsten salts, tantalum salts, molybdenum salts, zirconium salts.

Preferably, in step 3, the following steps are completed in an anhydrous glove box: dissolving the filler precursor material by using an anhydrous solvent, adding the filler precursor material into a fully dried carbon carrier material, sealing the carbon carrier material, and then removing the carbon carrier material from a glove box to prevent water absorption and hydrolysis of the mixture; the means of thorough mixing of the filler precursor solution with the carbon support material includes, but is not limited to, one or a combination of several of mechanical stirring, ultrasonic dispersion, high-speed shearing, ball milling; the mixing time is 0.5-24 hours.

The reduced pressure adsorption assistance means includes, but is not limited to, vacuum degassing of the carbon support; preferably, the sample is sealed by an elastic sealing bag, placed in a vacuum drying oven, vacuumized for 0.5-4 hours at normal temperature, and then air is introduced into the vacuum drying oven. The transition metal salt solution is more introduced into the carrier pore canal by the pressure difference.

More preferably, in step 3, the mixing of the filler precursor solution and the carbon support material may be performed in a separate step to maximize the filling, i.e., the precursor solution is added to the carbon support in separate steps, and after each addition, the filler precursor solution is added for a second time after the solid-liquid separation and drying process in step 4.

Preferably, in step 4, the mixed solution obtained in step 3 is subjected to solid-liquid separation and drying treatment to remove the solvent for dissolving the filler precursor, and fix the filler precursor inside the micropores of the carbon support material; the solid-liquid separation mode comprises any one or a combination of a plurality of rotary evaporation, suction filtration, freeze drying and high-speed centrifugal separation.

In step 4, the drying treatment is to further reduce the content of impurities such as solvents in the modified carbon support material, and the drying mode is preferably vacuum drying, wherein the drying temperature is 70-300 ℃ and the drying time is 2-36 h.

Preferably, in step 5, the high temperature treatment is performed under a specific atmosphere to convert the filler precursor material (transition metal salt) into a transition metal oxide, which may also be reduced to a lower valence oxide or corresponding transition metal as desired, as filled in the carbon support material. The specific atmosphere comprises an oxidizing atmosphere or a reducing atmosphere, and the purpose of the specific atmosphere is to obtain fillers with different oxidation states; before heat treatment (or heat treatment at lower temperature), transition metal salt or amorphous transition metal oxide is arranged in the carbon carrier holes, and metal oxide with better crystallization can be obtained after heat treatment under an oxidizing atmosphere; the low-valence metal oxide or metal simple substance can be obtained after heat treatment under the reducing atmosphere.

Preferably, the high temperature treatment is performed under a reducing atmosphere to obtain a low-valence metal oxide or metal simple substance having a lower resistivity.

The specific atmosphere is preferably: the balance gas is inert gas or mixed gas containing inert gas, the oxygen content in the oxidizing atmosphere is 0.1-5%, and the balance is inert gas.

The reducing gas in the reducing atmosphere comprises hydrogen or ammonia; the content of the reducing gas is 1-10%, and the balance is inert gas. The inert gas includes nitrogen, argon, helium and the like.

In step 5, the high temperature treatment program comprises at least one heating section and at least one constant temperature section; the heating rate range of the heating section is 1-10 ℃/min; the temperature range of the constant temperature section is 300-950 ℃; the constant temperature time is 1-12 h.

The carbon carrier material obtained by the preparation method comprises a carbon material and a filler filled in the carbon material, wherein the filler is a transition metal filler, and the transition metal filler is a metal simple substance and/or a metal oxide; the metal simple substance comprises one or a combination of a plurality of metal simple substances of titanium, cerium, niobium, tungsten, tantalum, molybdenum and zirconium, and the metal oxide comprises one or a combination of a plurality of titanium, cerium, niobium, tungsten, tantalum, molybdenum and zirconium; the mass content of the filler is 2 to 50%, preferably 10 to 25%.

Preferably, the mass content of the filler in the transition metal oxide-filled carbon support material is primarily dependent on the pore volume of the carbon support material selected; the mass content of the filler is 2-50%; preferably, the mass content of the filler is 10-25%;

after being filled by the filler, the pore volume of the carbon carrier material is reduced by more than 15 percent; preferably, the pore volume of the carbon support material is reduced by more than 25%, and more preferably, the pore volume of the carbon support material is reduced by more than 35%.

A supported noble metal-based catalyst comprises the carbon carrier material and an active component supported on the carbon carrier material, wherein the active component is noble metal or a combination of noble metal and transition metal,

the noble metal comprises one or a combination of several of gold, silver, ruthenium, rhodium, palladium, osmium, iridium and platinum.

As a more preferable technical scheme, the noble metal comprises at least one of platinum, ruthenium, palladium and iridium.

The mass content of noble metal in the noble metal-based catalyst is 5-70%.

The use of an electrocatalyst for an electrochemical energy conversion device comprising any one of a fuel cell, an electrolysis cell, a metal air cell.

In summary, due to the adoption of the technical scheme, the beneficial effects of the invention are as follows:

the transition metal oxide is filled into the pore canal of the porous carbon carrier, so that the number of micropores and pore volume are greatly reduced, and the noble metal is distributed on the outer surface of the carbon carrier material as much as possible under the condition of not affecting the conductivity of the carrier, so that the utilization rate of the noble metal is improved; in addition, the transition metal oxide formed on the surface of the shallow hole of the carbon carrier has stronger interaction with platinum, so that the platinum can be better dispersed on the carrier, and platinum particles can be prevented from falling off, thereby improving the activity and stability of the catalyst.

According to the technical scheme, in the preparation process of the carbon carrier material, the filler precursor material and the carbon carrier are fully combined in an oxidizing solution pretreatment and decompression adsorption mode, and the high-temperature treatment atmosphere and the high-temperature treatment mode are fully optimized, so that the carbon carrier material has the technical effect of high noble metal utilization rate in the whole preparation process.

In the technical scheme of the invention, the electrocatalyst prepared by the carbon carrier material, such as a platinum-based electrocatalyst, has higher electrocatalytic activity, conductivity and durability.

Drawings

FIG. 1 is an XRD pattern of a carbon support material;

FIG. 2 is an XRD pattern of a catalyst;

FIG. 3 is a graph of catalyst performance testing for half-cells;

FIG. 4 is a graph of a catalyst half cell durability test;

FIG. 5 is a graph of single cell carbon monoxide adsorption and desorption;

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

Example 1

The embodiment provides a preparation method of a carbon carrier material for an electrocatalyst, which specifically comprises the following preparation steps:

s1, weighing 20g of carbon black, placing in a 10mol/L nitric acid aqueous solution, heating and refluxing for 5 hours at 120 ℃, filtering and washing to be neutral, freeze-drying for 24 hours, and collecting the oxidized carbon black material.

Weighing 20g of carbon fiber, placing in concentrated sulfuric acid, heating and refluxing at 60 ℃ for 6 hours, filtering and washing to be neutral, freeze-drying for 24 hours, and collecting the oxidized carbon fiber material.

S2, weighing 1g of carbon black and 1g of carbon fiber after oxidation treatment respectively in a grinding bottle, uniformly mixing, and drying in a 150-DEG oven for later use; the vial was sealed and transferred to a glove box.

S3, weighing 0.9g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 9mL of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain absolute ethyl alcohol solution of the niobium pentachloride. Adding the niobium pentachloride ethanol solution into carbon powder, stirring uniformly, sealing a grinding bottle by using a balloon and a binding belt, and removing the grinding bottle from a glove box. After the obtained mixture is dispersed by ultrasonic and magnetically stirred for 30min, the sealed ground bottles are placed into a vacuum drying oven, vacuumizing is carried out for 10min, the vacuum degree is reduced, the mixture is taken out and magnetically stirred for 30min, then the mixture is placed into the vacuum drying oven, vacuumizing is carried out, air is introduced, and the process is repeated for 4 times, so that the niobium pentachloride ethanol solution is more introduced into the pore channels of the carbon carrier.

And S4, removing the ethanol solvent in the mixture obtained in the step S3 through rotary evaporation, transferring to a vacuum drying oven, and vacuum drying at 75 ℃ for 2 hours to further remove the solvent. The resulting carbon material was placed in an oven and dried overnight at 200 ℃ to allow the niobium chloride to be oxidized and cured to niobium oxide, then washed thoroughly with deionized water to free of chloride ions, and dried overnight in vacuo at 150 ℃.

S5, placing the dried carbon material in a tube furnace, introducing argon-hydrogen mixed gas (the hydrogen content is 5%), heating to 500 ℃ at a heating rate of 5 ℃ per minute, keeping the temperature for 4 hours, naturally cooling, and taking out a sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the carbon carrier filled with niobium oxide holes.

Preparing a fuel cell catalyst by adopting the carbon carrier filled with the niobium oxide and testing the performance of the fuel cell catalyst;

the method for preparing the fuel cell catalyst with the platinum content of 50wt% comprises the following steps: 0.2g of the prepared niobium oxide pore-filling carbon carrier material is weighed and placed in an oven for drying at 150 ℃ for 2 hours.

Platinum nanoparticles were supported on the surface of niobium oxide pore-filled carbon supports as described in patent (CN 1226086C). Placing the obtained sample in a tube furnace, introducing argon-hydrogen mixed gas (hydrogen content is 5%), heating to 600 ℃ at a rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, and taking out the sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the platinum catalyst loaded by the niobium oxide carbon composite carrier.

Example 2

S1, weighing 20g of graphene, placing in concentrated nitric acid, heating and refluxing at 80 ℃ for 6 hours, filtering and washing to be neutral, freeze-drying for 24 hours, and collecting the oxidized carbon material.

S2, weighing 2g of oxidized graphene in a grinding bottle, and drying in a baking oven at 150 ℃ for later use. The vial was sealed and transferred to a glove box.

S3, weighing 0.9g of titanium tetrachloride in a glove box, placing in a test tube, and adding 8ml of absolute ethyl alcohol to completely dissolve the titanium tetrachloride to obtain an absolute ethyl alcohol solution of the titanium tetrachloride. Adding the titanium tetrachloride ethanol solution into carbon powder, and uniformly stirring. The resulting mixture was sheared at high speed in a glove box for 2h, the vial was sealed with a balloon and a tie, and removed from the glove box. Placing the sealed ground bottle into a vacuum drying oven, vacuumizing for 10min, and introducing air into the vacuum drying oven, and repeatedly vacuumizing and ventilating for 4 times to enable the titanium tetrachloride ethanol solution to enter into the carbon carrier pore channels more.

S4, removing the ethanol solvent in the mixture obtained in the step S3 through high-speed centrifugal separation, and transferring the sample to a vacuum drying oven for vacuum drying at 75 ℃ for 2 hours. The resulting carbon material was placed in an oven, dried overnight at 200 ℃, then thoroughly washed with deionized water to be free of chloride ions, and then dried under vacuum at 150 ℃ overnight.

S5, placing the dried carbon material in a tube furnace, introducing argon-hydrogen mixed gas (the hydrogen content is 7%), heating to 600 ℃ at a heating rate of 10 ℃ per minute, keeping the temperature for 3 hours, naturally cooling, and taking out a sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the carbon carrier filled with titanium oxide.

Preparing a fuel cell catalyst by adopting the carbon carrier filled with titanium oxide and testing the performance of the catalyst;

a fuel cell catalyst having a platinum content of 50% was prepared: 0.2g of the prepared carbon support material filled with titanium oxide was weighed and dried in an oven at 150℃for 2 hours. Platinum nanoparticles were supported on the surface of a titanium oxide pore-filled carbon support as described in the patent (CN 1226086C). Placing the obtained sample in a tube furnace, introducing argon-hydrogen mixed gas (hydrogen content is 5%), heating to 600 ℃ at a rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, and taking out the sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the platinum catalyst loaded by the titanium oxide carbon composite carrier.

Example 3

S1, weighing 20 g of carbon nano tubes, placing the carbon nano tubes in 10 mol of nitric acid aqueous solution per liter, heating and refluxing the carbon nano tubes at 80 ℃ for 12 hours, filtering and washing the carbon nano tubes to be neutral, freeze-drying the carbon nano tubes for 24 hours, and collecting the oxidized carbon material.

S2, weighing 2g of the oxidized carbon carrier, and drying in a baking oven at 150 ℃ for standby. The vial was sealed and transferred to a glove box.

S3, weighing 1.2g of cerium nitrate in a glove box, placing the cerium nitrate in a test tube, and adding 15ml of acetone to completely dissolve the cerium nitrate to obtain an acetone solution of the cerium nitrate. Adding cerium nitrate acetone solution into carbon powder, stirring uniformly, sealing a grinding bottle by using a balloon and a binding belt, and removing the grinding bottle from a glove box. After the obtained mixture is dispersed for 30min by ultrasonic, the sealed grinding bottle is placed into a vacuum drying oven, after the vacuum drying oven is vacuumized for 10min, air is introduced into the vacuum drying oven, after the mixture is taken out, the mixture is dispersed for 30min by ultrasonic, then vacuumized and air is introduced again, and the process is repeated for 4 times, so that cerium nitrate acetone solution is more introduced into a pore channel of a carbon carrier.

And S4, removing the solvent in the mixture obtained in the step S3 through suction filtration, transferring to a vacuum drying oven, and vacuum drying at 75 ℃ for 2 hours to further remove the solvent. The resulting carbon material was placed in an oven and dried overnight at 200 ℃ to allow the cerium nitrate to be oxidatively cured to cerium oxide, then thoroughly washed with deionized water to be nitrate ion free, and then dried overnight in vacuo at 150 ℃.

S5, placing the dried carbon material in a tube furnace, introducing argon-hydrogen mixed gas (the hydrogen content is 3%), heating to 600 ℃ at a heating rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, and taking out a sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the carbon carrier filled with cerium oxide.

Preparing a fuel cell catalyst by adopting the carbon carrier filled with cerium oxide and testing the performance of the catalyst;

a fuel cell catalyst having a platinum content of 50wt% was prepared: 0.2g of the prepared carbon carrier material with cerium oxide filled holes is weighed and placed in an oven for drying at 150 ℃ for 2 hours. Platinum nanoparticles were supported on the surface of a cerium oxide-filled carbon support as described in the patent (CN 1226086C). Placing the obtained sample in a tube furnace, introducing argon-hydrogen mixed gas (hydrogen content is 5%), heating to 600 ℃ at a rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, and taking out the sample after the argon-hydrogen mixed gas is purged completely by nitrogen, thereby obtaining the platinum catalyst loaded by the cerium oxide carbon composite carrier.

Example 4

S1, weighing 20g of carbon black, placing in 10 mol of nitric acid aqueous solution per liter, heating and refluxing at 80 ℃ for 12 hours, filtering and washing to be neutral, freeze-drying for 24 hours, and collecting the oxidized carbon material.

S3, weighing 1g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 10ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain absolute ethyl alcohol solution of the niobium pentachloride. Adding the niobium pentachloride ethanol solution into carbon powder, stirring uniformly, sealing a grinding bottle by using a balloon and a binding belt, and removing the grinding bottle from a glove box. After the obtained mixture is dispersed for 30min by ultrasonic, the sealed grinding bottle is placed into a vacuum drying oven, after the vacuum drying oven is vacuumized for 10min, air is introduced into the vacuum drying oven, after the air is taken out, the air is dispersed for 30min by ultrasonic, and then vacuumized and air is introduced again, and the process is repeated for 4 times, so that niobium pentachloride ethanol is more introduced into a pore channel of a carbon carrier.

And S4, removing the ethanol solvent in the mixture obtained in the step S3 through suction filtration, transferring to a vacuum drying oven, and drying at 75 ℃ for 2 hours to further remove the solvent. The resulting carbon material was placed in an oven and dried overnight at 200 degrees to allow the niobium chloride to be oxidatively cured to niobium oxide, then thoroughly washed with deionized water to remove chloride ions, and then dried overnight under 150 degrees vacuum.

S5, placing the dried carbon material in a tube furnace, introducing argon-hydrogen mixed gas (the hydrogen content is 3%), heating to 600 ℃ at a heating rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, and taking out a sample after the argon-hydrogen mixed gas is purged completely by nitrogen to obtain the carbon carrier filled with niobium oxide holes.

a fuel cell catalyst having a platinum content of 50wt% was prepared: 0.2g of the prepared niobium oxide pore-filling carbon carrier material is weighed and placed in an oven for drying at 150 ℃ for 2 hours. Platinum nanoparticles were supported on the surface of niobium oxide pore-filled carbon supports as described in patent (CN 1226086C). Placing the obtained sample in a tube furnace, introducing argon-hydrogen mixed gas (hydrogen content is 5%), heating to 600 ℃ at a rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, purging the argon-hydrogen mixed gas with nitrogen, and taking out the sample to obtain the platinum catalyst loaded by the niobium oxide carbon composite carrier.

Example 5

The specific preparation steps of the platinum catalyst supported on the niobium oxide carbon composite carrier in this embodiment are the same as those in embodiment 4, and the difference is that in step S3: the amount of transition metal salt solution used.

S3, weighing 0.8g of niobium pentachloride in a glove box, placing in a test tube, and adding 10 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain an absolute ethyl alcohol solution of the niobium pentachloride.

Example 6

This example provides a niobium oxide carbon composite carrier supported platinum catalyst, which is prepared in the same steps as in example 5, except that S3, 10 ml of absolute ethanol containing 0.8g of niobium pentachloride is added to the carbon carrier twice, and steps S3 and S4 are repeated each time. The method comprises the following steps:

s3, weighing 0.8g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 10 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain absolute ethyl alcohol solution of the niobium pentachloride. 10 ml of absolute ethanol of niobium pentachloride was added to the carbon support in two portions. Firstly, 5 milliliters of niobium pentachloride ethanol solution is measured and added into carbon powder, the mixture is stirred uniformly, an abrasive bottle is sealed by a balloon and a binding belt, and the mixture is removed from a glove box. After the obtained mixture is dispersed for 30min by ultrasonic, the sealed grinding bottle is placed into a vacuum drying oven, after the vacuum drying oven is vacuumized for 10min, air is introduced into the vacuum drying oven, after the air is taken out, the air is dispersed for 30min by ultrasonic, and then vacuumized and air is introduced again, and the process is repeated for 4 times, so that niobium pentachloride ethanol is more introduced into a pore channel of a carbon carrier.

And (3) placing the sample obtained in the step (S4) into a glove box, adding the rest 5 ml of niobium pentachloride ethanol solution in the step (S3) into the sample obtained in the step (S4), repeating the step (S3) and the step (S4), and drying to obtain a powder sample.

Example 7

S3, weighing 1.2 g of niobium pentachloride in a glove box, placing in a test tube, and adding 10 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain an absolute ethyl alcohol solution of the niobium pentachloride.

Example 8

The specific preparation steps of the platinum catalyst supported on the niobium oxide carbon composite carrier in this embodiment are the same as those in embodiment 4, and the difference is that in step S3: the transition metal salt solution is prepared and the solvent dosage is different.

S3, weighing 1 g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 5 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain an absolute ethyl alcohol solution of the niobium pentachloride.

Example 9

S3, weighing 1 g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 15 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain an absolute ethyl alcohol solution of the niobium pentachloride.

Example 10

The specific preparation steps of the platinum catalyst supported on the niobium oxide carbon composite carrier provided in this embodiment are the same as those in embodiment 4, except for step S3, and the dispersion modes are different. The resulting mixture was dispersed by high speed shearing (10000 revolutions per minute) for 2 hours, and the transition metal alcohol solution was allowed to enter into the carbon pores.

S3, weighing 1 g of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 10 ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain an absolute ethyl alcohol solution of the niobium pentachloride. Adding the niobium pentachloride ethanol solution into carbon powder, and uniformly stirring. The resulting mixture was sheared at high speed in a glove box for 2 hours, the vial was sealed with a balloon and a tie, and removed from the glove box. And (3) placing the sealed ground bottle into a vacuum drying oven, vacuumizing for 10 minutes, and then introducing air into the vacuum drying oven, and repeatedly vacuumizing and ventilating for 4 times to enable the transition metal salt solution to enter into the pore channels of the carbon carrier more.

Example 11

The specific preparation steps of the platinum catalyst supported by the niobium oxide carbon composite carrier provided in this embodiment are the same as those in embodiment 4, except that in step S4, the solid-liquid separation modes are different.

S4, after removing the ethanol solvent by rotary evaporation, transferring to a vacuum drying oven, and drying at 75 ℃ for 2 hours to further remove the solvent. The resulting carbon material was placed in an oven and dried overnight at 200 degrees to allow the niobium chloride to be oxidatively cured to niobium oxide, then thoroughly washed with deionized water to remove chloride ions, and then dried overnight under 150 degrees vacuum.

Comparative example 1

In this comparative example 1, a method for producing a niobium oxide pore-filled carbon support, and a fuel cell catalyst produced using the support, are provided.

Specifically, the preparation process of the niobium oxide pore-filled carbon carrier is basically the same as that of example 4, except that step S1 is different: s1, directly using carbon black without oxidation treatment; the untreated carbon black is then used directly as support material.

Comparative example 2

In this example 2, a method for producing a niobium oxide pore-filled carbon support, and a fuel cell catalyst produced using the support are provided. Specifically, the preparation process of the niobium oxide pore-filled carbon carrier is basically the same as that of example 4, except that step S3 is different:

S3, weighing 1 gram of niobium pentachloride in a glove box, placing the niobium pentachloride in a test tube, and adding 10ml of absolute ethyl alcohol to completely dissolve the niobium pentachloride to obtain absolute ethyl alcohol solution of the niobium pentachloride. And (3) removing the prepared absolute ethanol solution of the niobium pentachloride from the glove box, directly adding the absolute ethanol solution of the niobium pentachloride into carbon powder in an aerobic and water environment, and uniformly stirring. Sealing the grinding bottle with a balloon and a binding belt, ultrasonically dispersing the obtained mixture for 30min, placing into a vacuum drying oven, vacuumizing for 10min, introducing air into the vacuum drying oven, taking out, ultrasonically dispersing for 30min, vacuumizing again, introducing air again, and repeating for 4 times.

Comparative example 3

This comparative example 3 provides a carbon support material using ammonium niobate oxalate hydrate as a niobium oxide precursor and ultrapure water as a solvent.

The preparation method of comparative example 3 is substantially the same as in example 4, except that step S3 is different:

1.2 g of ammonium niobate oxalate hydrate was weighed, placed in a test tube, and 10ml of ultrapure water was added to completely dissolve the ammonium niobate oxalate hydrate, to obtain an aqueous solution of the ammonium niobate oxalate hydrate. Adding ammonium niobate oxalate aqueous solution into carbon powder, and stirring uniformly. Sealing the grinding bottle by using a balloon and a binding belt, performing ultrasonic dispersion on the obtained mixture for 30 minutes, putting the mixture into a vacuum drying oven, vacuumizing for 10 minutes, introducing air into the vacuum drying oven, taking out, performing ultrasonic dispersion for 30 minutes, vacuumizing again, introducing air again, and repeating the steps for 4 times.

The carbon support materials of comparative examples 1-3 were subjected to performance testing and are summarized in Table 1.

Table 1 is a summary table of test data for carbon supports

As shown in table 1, in the performance data of the carbon support materials of example 4 and comparative example 1, when the carbon support was not subjected to the oxidation pretreatment to remove impurities, the metal oxide content filled in the carbon pores was decreased, and the corresponding specific surface area and Kong Rongxia were decreased in width. Therefore, on one hand, impurities in the carbon holes can be removed by oxidation treatment, and carbon hole expansion is performed; on the other hand, the oxidation treatment can lead the carbon carrier to have a plurality of oxygen-containing functional groups, and the interaction force of the solvent, the metal precursor and the metal oxide and the oxygen-containing functional groups can be utilized to facilitate the metal oxide to enter into the carbon holes.

The difference between comparative example 2 and example 4 is that the experiment was performed in an aerobic and water environment. In an aerobic and water environment, niobium chloride is extremely easy to hydrolyze and oxidize, so that solid precipitation is generated, and cannot enter into micropore channels and is deposited on the outer surface of a carrier. Therefore, the pore volume and specific surface area of the composite support obtained in comparative example 1 were not greatly reduced, and the metal oxide at the outer surface area significantly increased the resistivity of the catalyst.

Comparative example 3 experiments were performed directly in a water-aerobic environment using ammonium niobate oxalate hydrate as a precursor and water as a solvent. On the one hand, the dispersion of the carbon support in the aqueous solution is poor due to the hydrophobicity of the carbon support; in addition, because of the poor wettability of the carbon support by water, the resistance to entry into the support pores is high, and therefore the metal oxide is ultimately mostly on the support surface and does not enter the support pores. Accordingly, the specific surface area and pore volume of the sample are not greatly reduced, and the resistivity is increased.

Comparative example 4

Comparative example 4 provides a method of preparing a carbon support, and a fuel cell catalyst prepared using the support.

The preparation procedure is the same as in example 4, except that the heat treatment temperature for the support in step S5 is different.

S5, placing the dried carbon material in a tube furnace, introducing argon-hydrogen mixed gas (the hydrogen content is 3%), heating to 400 ℃ at a heating rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, blowing the argon-hydrogen mixed gas clean by nitrogen, and taking out a sample to obtain the carbon carrier filled with niobium oxide holes.

Comparative example 5

This comparative example 5 provides a method for preparing a carbon support, and a fuel cell catalyst prepared using the support. The preparation procedure is the same as in example 4, except that S5 is not heat treated (no heat treatment is performed on the carbon support after pore filling), and S6 is not heat treated on the synthesized catalyst during the preparation of the catalyst.

Specifically, the preparation method of the carbon support is substantially the same as that of example 4, except that step S5 is absent in this comparative example 4, i.e., the carbon support after pore-filling is not subjected to high-temperature heat treatment.

The synthesized catalyst is not subjected to heat treatment during the preparation of the catalyst. Namely:

in the preparation of the catalyst in S6, the synthesized catalyst is not subjected to heat treatment either. Namely: the carbon support obtained by drying S4 was directly used to prepare a fuel cell catalyst having a platinum content of 50 wt%: 0.2 g of the prepared niobium oxide pore-filling carbon carrier material is weighed and placed in an oven for drying at 150 ℃ for 2 hours. Platinum nanoparticles were supported on the surface of niobium oxide pore-filled carbon supports as described in patent (CN 1226086C).

Comparative example 6

This comparative example provides a method for preparing a catalyst, specifically, using the same carbon support material as in example 4. The difference is that the modified carbon carrier is not subjected to high temperature treatment, but the synthetic platinum carbon catalyst is subjected to high temperature treatment.

Specifically, the preparation method of the catalyst specifically comprises the following steps:

the carbon support obtained by drying S4 was directly used to prepare a fuel cell catalyst having a platinum content of 50 wt%: 0.2 g of the prepared niobium oxide pore-filling carbon carrier material is weighed and placed in an oven for drying at 150 ℃ for 2 hours. Platinum nanoparticles were supported on the surface of niobium oxide pore-filled carbon supports as described in patent (CN 1226086C). Placing the obtained sample in a tube furnace, introducing argon-hydrogen mixed gas (hydrogen content is 5%), heating to 600 ℃ at a rate of 5 ℃ per minute, keeping the temperature for 2 hours, naturally cooling, purging the argon-hydrogen mixed gas with nitrogen, and taking out the sample to obtain the platinum catalyst loaded by the niobium oxide carbon composite carrier.

Comparative example 7

The catalyst was synthesized using carbon black which had not been subjected to any treatment and had not been filled with carbon pores as a carbon support, and the procedure for the synthesis of the catalyst was the same as that for the preparation of the catalyst in example 4.

The specific test criteria for the half-cell activity test, half-cell durability test, and single cell activity test are as follows:

half cell activity test standard: the catalyst was activated by cyclic voltammetry scanning for 30 cycles with a nitrogen saturated perchloric acid solution at a concentration of 0.1 mol/liter as electrolyte, voltage window 0-1.2 volts (vs. rhe), scanning rate 50 millivolts per second. After the cyclic voltammogram is stabilized, the cyclic voltammogram is continuously recorded for 3 circles in a perchloric acid solution with the concentration of 0.1 mol/L saturated by nitrogen at the scanning speed of 50 millivolts/second, and the potential scanning range is 0.05V-1.2V. (vs. RHE)

Half cell endurance test standard: the voltage window is 0.6-0.95V, the scanning speed is 100 mV/s to measure the low potential durability, the aging atmosphere is nitrogen, and the activation and activity test is referred to the activity test standard.

Single cell activity test standard:

(1) Catalyst slurry preparation: mixing a catalyst sample to be detected with a membrane solution, deionized water and isopropanol according to a certain proportion, wherein the ratio (I/C) of proton conducting resin in the membrane solution to carbon carriers in the catalyst is 0.8, and the volume ratio of water to isopropanol is 3:7; ultrasonic processing is carried out for more than 30 minutes by using ultrasonic with the power not lower than 200 watts, so that the slurry is uniformly mixed to form cathode and anode catalyst slurry respectively;

(2) Catalyst Coated Membrane (CCM) preparation: according to the anode Pt load of 0.1mg/cm < 2 >, the cathode Pt load of 0.4mg/cm < 2 > and the effective area of more than or equal to 25cm < 2 >, respectively spraying anode and cathode catalyst slurry to two sides of a proton exchange membrane by utilizing an ultrasonic spraying machine to prepare an anode catalytic layer and a cathode catalytic layer, and drying to obtain the CCM.

Single cell activity test: the anode was supplied with 0.2 liters per minute of high purity H2 (99.999%), the cathode potential was maintained at 0.05 volts (vs. rhe) at 100% humidity, a CO/N2 (CO, 5 vol.%) mixture was introduced to the cathode, purged for 5 minutes at a flow rate of 0.2 liters per minute, then the cathode gas was switched to N2 at a flow rate of 0.2 liters per minute, and the purging was continued for 45 minutes maintaining the same gas humidity. After the purging, 3 CV scans were performed in a potential interval of 0.05-1.0 volts (vs. RHE), and the scan rate was set at 50 mV/s.

In the schemes of comparative examples 4 to 6, XRD patterns shown in FIG. 1 were obtained by changing the heat treatment conditions or not of the carbon support after the carbon pores and XRD testing the carbon support material in the above scheme; FIG. 1 is an XRD pattern of the pore-filled carbon carrier obtained in example 4 and comparative examples 4, 5 and 6; as can be seen from FIG. 1, niobium chloride has been substantially converted to niobium oxide after drying overnight at 200℃with or without heat treatment having less effect on the specific surface area, pore volume and resistivity of the composite support produced.

As shown in FIG. 1, when the carbon support after pore filling was not subjected to a high-temperature heat treatment (comparative examples 5 to 6) and a heat treatment temperature (400 ℃) heat treatment (comparative example 4), the metal or the metal oxide obtained was amorphous. And after heat treatment of the carbon support after pore filling at 600 ℃ (example 4), the obtained metal oxide has stable crystal structure.

The XRD pattern of the carbon carrier loaded with platinum nanoparticles after filling is shown in figure 2.

As shown in fig. 2, examples 4, comparative example 2, comparative example 3, comparative examples 5 and 6, and comparative example 7; the particle diameters of the obtained pore-filling carbon carrier loaded platinum nano particles are shown in the following table:

TABLE 2

	Example 4	Comparative example 2	Comparative example 3	Comparative example 5	Comparative example 6	Comparative example 7
							Particle size (nm)	2.13	2.45	3.51	2.09	2.59	2.93

The carbon support-supported platinum after pore filling of the metal oxide has a smaller platinum particle diameter than the conventional platinum carbon catalyst (comparative example 7), and the platinum dispersion is improved due to the strong interaction between the metal oxide and the platinum particles. As can be seen from comparative examples 5 and 6, after the platinum catalyst supported on the pore-filled carbon carrier was subjected to a high-temperature heat treatment at 600℃for 2 hours, the platinum particle diameter was increased from 2.09nm to 2.59nm only by 24%, which fully proves that the platinum particles supported on the carbon carrier after the pore filling had a good anti-sintering effect.

Comparative example 2 a pore-filling experiment of carbon support was carried out in an aerobic environment with water, and since niobium chloride was easily hydrolyzed to form precipitate, and was not smoothly introduced into pores of carbon support to be deposited on the outer surface of carbon support, the specific surface area and Kong Rongxia drop width were smaller than those of example 4. In addition, the metal oxide at the surface also contributes to the dispersion of the platinum particles due to the strong interaction of the metal oxide with the platinum particles, and the resulting platinum particle size (2.45 nm) is smaller than conventional (2.93 nm). However, the metal oxide supported on the outer surface of the carbon material has a remarkable effect on the resistivity of the carbon support and the catalyst produced, and it is difficult to prevent the platinum-based nanoparticles from entering into the micropores.

Comparative example 3 in which ultrapure water was used as a solvent, the metal precursor aqueous solution was hardly introduced into the pores of the support, so that most of the niobium oxide was carried on the outer surface of the carbon material, and finally only a small portion of the metal oxide was on the surface and inside of the support, the pore-filling effect was not ideal, and the specific resistance of the support was significantly affected. The platinum carbon catalyst supported by the carrier has a larger platinum particle diameter (3.51 nm).

Half cell performance tests were performed on the catalysts of example 4 and comparative examples 5-6, and comparative examples 2, 3, and 7, as shown in fig. 3, CV curves and ECSA results after loading with platinum nanoparticles;

Table 3 is a summary of electrochemically active areas

The catalyst without any transition metal oxide (comparative example 7) had a platinum particle diameter of 2.93nm, a resistivity of 0.06775. OMEGA.m, and a corresponding electrochemically active area of 80.05m ² /g。

Comparative example 2 compared with comparative example 7, after niobium oxide was introduced, a part of the metal oxide was on the surface of the support, and although the interaction force between the metal oxide and platinum improved the dispersion of platinum (platinum particle diameter was 2.45 nm), the electrochemical active area of the sample was reduced to 60.22m due to the increased resistivity of the support (0.0597 → 0.1645 Ω m) of the surface metal oxide, which affected the electron transport ² And/g. The pore-filling effect of the oxide in comparative example 3 was not ideal, and the metal oxide on the surface of the support resulted in an increase in the resistivity of the support, and the particle size of the supported platinum particles was also large, resulting in a significant decrease in the corresponding electrochemically active area (57.29 m ² /g)。

In example 4, most of niobium oxide is successfully filled in the pore canal of the carbon carrier, the metal oxide in the pore canal does not increase the resistivity of the carrier, the pore volume of the carbon carrier after pore filling is reduced by more than 50%, the probability that platinum nano particles enter micropores of the carbon carrier is reduced, most of platinum nano particles are carried on the outer surface of the carrier, meanwhile, the platinum carbon catalyst prepared by the carrier has better dispersion, and the platinum particle size is only 2.13nm. The catalyst prepared in example 4 had a significantly improved electrochemical specific surface area (107.27 m ² And/g), it is described that filling the carbon pores with a transition metal oxide helps to increase the utilization of platinum.

The electrochemical active areas of comparative example 5 and comparative example 6 are also significantly improved compared with those of comparative example 7.

Half cell durability tests were performed on the catalysts of example 4 and comparative examples 5, 6, and 7, and the results are shown in fig. 4:

table 4 shows electrochemical specific surface areas ECSA before and after the half cell low potential endurance cycle of the comparative example and example

Filling the carbon pores with metal oxide can raise the utilization of platinum particle in the catalyst and increase the electrochemical active area of the catalyst (figure 3). In addition, due to the strong interaction between the metal oxide and the platinum particles, the dissolution, the shedding and the agglomeration of the platinum particles can be prevented, so that the stability of the catalyst is also obviously improved. As shown in table 4 and fig. 4, the platinum catalyst supported on the carbon carrier after pore filling in example 4 and comparative example 6 was subjected to a high temperature heat treatment, so that a strong interaction between the platinum particles and the carrier occurred, and the stability thereof was significantly improved compared with the conventional catalyst (comparative example 7). In comparative example 5, although the utilization of platinum is improved, the interaction between platinum particles and the carrier is weaker than in the example without high temperature heat treatment, and thus the stability is somewhat inferior, but still superior to that of the unmodified, pristine carbon-supported platinum-carbon catalyst.

The activity test was performed on the single cells of comparative example 3, comparative example 4 and example 4, in which the carbon carriers were loaded with platinum nanoparticles, and the carbon monoxide adsorption and desorption curves of the single cells are shown in fig. 5.

Table 5 shows the results of the electrochemically active areas

Catalyst	Comparative example 3	Comparative example 4	Example 4
				Electrochemically active area m ² /g	54.45	58.60	79.17

In comparative example 3, since the metal oxide has a certain influence on the conductivity of the catalyst and further affects the electron conduction rate in the presence of oxygen and water on the surface of the carbon support, the active area thereof is relatively low compared with that of the unmodified catalyst. In example 4, since the transition metal oxide is inside the pores of the carbon support, the conductivity of the support is not affected, and most of the platinum particles are on the outer surface of the support, the utilization ratio of platinum is high, so that the active area of the catalyst is increased, which means that the utilization ratio of platinum is significantly improved.

Table 6 is a summary table of test data for modified carbon supports

As shown in table 6, examples 5 and 7 are different from example 4 in the addition amount of the metal precursor niobium chloride. As the amount of metal precursor increases, the metal oxide content of the sample increases first and then reaches a plateau. Accordingly, the specific surface and pore volume of the sample, which are related to the content of metal oxides, will also reach a certain saturation value.

Example 6 on the basis of example 5, the precursor liquid was added in portions. In the case where the precursor solution concentration and the precursor volume are the same, the precursor solution is added (example 6) in two portions, and more metal oxide is filled in the cells than in one portion (example 5). The addition of the metal precursor liquid in multiple times is beneficial to improving the utilization rate of the metal precursor liquid and the metal content in the carbon carrier.

Example 4, example 8 example 9 the ethanol solvent used to dissolve the niobium pentachloride precursor was 10 ml, 5 ml and 15 ml, respectively. When the amount of solvent used to dissolve the metal precursor is small, the entire carbon support cannot be infiltrated, so that the metal oxide is unevenly filled, a part of the metal oxide is supersaturated, a part of the metal oxide is unfilled, and the final metal content is low. When the solvent is used in an excessive amount, the metal precursor solution is diluted and filled into the solution in the carbon pores, and the metal content is small, thus also resulting in a low niobium oxide content.

As can be seen from examples 4, 10 and 11, the dispersion mode and the solid-liquid separation mode of the metal precursor and the carbon support have less influence on the metal oxide content filled in the carbon pores and the specific surface area and pore volume of the carbon support.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims

1. A method for preparing a carbon support material, comprising the steps of:

step 2, drying the carbon carrier material;

step 3, adding a carbon carrier material into a solution containing a filler precursor material under the anhydrous and anaerobic condition to form a mixed solution, uniformly dispersing and mixing, and adsorbing the filler precursor solution into micropores of the carbon carrier material through reduced pressure adsorption, wherein the filler precursor material is a transition metal salt;

step 4, carrying out solid-liquid separation and drying treatment on the mixed solution obtained in the step 3, so that the filler precursor material is fixed in micropores of the carbon carrier material, and sample powder is obtained;

2. A process for preparing a carbon support material as claimed in claim 1, wherein,

in the step 1, the oxidizing solution comprises one or more of nitric acid, concentrated sulfuric acid, hydrogen peroxide, perchloric acid and potassium permanganate aqueous solution;

in step 1, the specific process of the pretreatment is as follows: mixing the carbon carrier material with the oxidizing solution, stirring, heating and refluxing at 50-150 ℃ for 0.5-24h at a stirring speed of 200-1000 rpm, and performing solid-liquid separation, washing and drying after the reaction to obtain the oxidized carbon carrier material.

3. The method for producing a carbon support material according to claim 1, wherein in step 2, the drying treatment temperature is 100 to 300 ℃, the drying time is 2 to 24 hours, and the water content in the carbon support material after the drying treatment is not more than 0.5%.

4. The method of preparing a carbon support material according to claim 3, wherein in step 3, the solvent selected for preparing the filler precursor solution is required to be capable of sufficiently dissolving the selected filler precursor without damaging the chemical structure and composition thereof, and the solvent includes any one or a combination of any several of methanol, ethanol, propanol, acetone, and chloroform;

The fully mixing mode of the filler precursor solution and the carbon carrier material comprises one or a combination of a plurality of mechanical stirring, ultrasonic dispersion, high-speed shearing and ball milling; the mixing time is 0.5-24 hours.

5. The method for preparing a carbon carrier material according to claim 1, wherein in step 4, the solid-liquid separation means comprises any one or a combination of several of rotary evaporation, suction filtration, freeze drying, and high-speed centrifugal separation; the drying treatment mode is vacuum drying, the vacuum drying temperature is 70-300 ℃, and the vacuum drying time is 2-36 h.

6. The method for producing a carbon support material according to claim 1, wherein in step 5, the high-temperature treatment is performed under a specific atmosphere including an oxidizing atmosphere, an inert atmosphere, or a reducing atmosphere, the oxygen content in the oxidizing atmosphere being 0.1 to 5%; the reducing gas in the reducing atmosphere comprises at least one of hydrogen or ammonia; the content of the reducing gas is 1-10%; the remaining gas is an inert gas.

7. The method of producing a carbon support material according to claim 5, wherein in step 5, the high temperature treatment program includes at least one temperature raising section and at least one constant temperature section, and the temperature raising rate of the temperature raising section ranges from 1 to 10 degrees per minute; the temperature range of the constant temperature section is 300-950 ℃; the constant temperature time is 1-12 hours.

8. The carbon support material obtained by the production method according to any one of claims 1 to 7, wherein the carbon support material comprises a carbon material and a filler filled in the carbon material, the filler is a transition metal filler, and the transition metal filler is a metal simple substance and/or a metal oxide; the metal simple substance comprises one or a combination of a plurality of metal simple substances of titanium, cerium, niobium, tungsten, tantalum, molybdenum and zirconium, and the metal oxide comprises one or a combination of a plurality of titanium, cerium, niobium, tungsten, tantalum, molybdenum and zirconium; the mass content of the transition metal filler is 2 to 50%, preferably 10 to 25%.

9. A supported noble metal-based catalyst, comprising the carbon support material of claim 8, and further comprising an active component supported on the carbon support material, wherein the active component comprises a noble metal, or a combination of a noble metal and a transition metal, and the noble metal comprises one or a combination of several of gold, silver, ruthenium, rhodium, palladium, osmium, iridium and platinum, and the mass content of the noble metal in the noble metal-based catalyst is 5-70%.

10. The use of an electrocatalyst for an electrochemical energy conversion device comprising any one of a fuel cell, an electrolysis cell, a metal air cell.