Method for synthesizing bimetal catalyst particles made of platinum and of another metal and use thereof in an electrochemical hydrogen production method

Abstract

A process for the synthesis of particles of bimetal catalyst based on platinum and on at least one second metal comprises the chemical reduction of a first platinum-based salt or complex and of at least one second salt or complex based on the second metal, the chemical reduction comprising the following stages: the preparation of a mixture comprising the first platinum-based salt or complex and the second salt or complex based on the second metal, in the presence of a pure reducing agent in the liquid form under ambient temperature and pressure conditions, the conditions being respectively defined as equal to 25° C. and 100 kPa; bringing the mixture to a temperature between approximately the freezing temperature of water and the freezing temperature of the reducing agent.

1 . A process for the synthesis of particles of bimetal catalyst based on platinum and on at least one second metal, comprising chemical reduction of a first platinum-based salt or complex and of at least one second salt or complex based on said second metal, said chemical reduction comprising the following stages:
 preparing a mixture comprising said first platinum-based salt or complex and said second salt or complex based on said second metal, in the presence of a pure reducing agent in the liquid form under ambient temperature and pressure conditions, said conditions being respectively defined as equal to 25° C. and 100 kPa; and   bringing said mixture to a temperature between approximately the freezing temperature of water and the freezing temperature of the reducing agent.   
     
     
         2 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , wherein the reducing agent is formic acid, the bringing to a temperature being carried out between approximately 0° C. and 8° C. 
     
     
         3 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , wherein the reducing agent is hydrazine (N 2 H 4 ), the bringing to a temperature being carried out between approximately 0° C. and 2° C. 
     
     
         4 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , further comprising the mixing of platinum salt or complex and of salt or complex of said second metal, in the presence of particles of carbon black or of metal oxide or of metal nitride or of metal carbide. 
     
     
         5 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , wherein the amount of reducing agent is greater than or equal to the amount necessary to carry out the chemical reduction of all of the platinum salts or complexes and of the salts or complexes of the second metal. 
     
     
         6 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , wherein the reaction is carried out in the presence of an additional energy source which makes it possible to accelerate the chemical reduction operation without promoting the growth of nanoparticles. 
     
     
         7 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 6 , wherein the additional energy source is an ultraviolet radiation source. 
     
     
         8 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 7 , wherein the ultraviolet radiation source emits in a wavelength range of between approximately 200 nm and 300 nm. 
     
     
         9 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , wherein the second metal is tin or ruthenium or molybdenum or cobalt. 
     
     
         10 . The process for the synthesis of particles of bimetal catalyst as claimed in  claim 9 , wherein the size distribution of said particles exhibits a median size of 4 nm and a standard deviation of 1.1. 
     
     
         11 . The use of the process for the synthesis of particles of bimetal catalyst as claimed in  claim 1 , in a method for the electrochemical production of hydrogen comprising a catalytic reforming reaction in the presence of said catalyst particles and of a gas mixture comprising hydrocarbon compounds. 
     
     
         12 . The use of the process for the synthesis of particles of bimetal catalyst as claimed in  claim 11 , wherein the gas mixture comprises carbon monoxide, carbon dioxide and methane.