Research For Durable Catalyst Of The Proton Exchange Membrane Fuel Cell

Durability of the catalyst is one of the limiting factors for the commercialization of the proton exchange membrane fuel cell?PEMFC?.Pt agglomeration and particle growth,Pt elemental loss and the catalyst support degradation are the three main factors leading to the degradation of the catalyst.In order to improve the durability of the fuel cell catalyst,this paper will study the two aspects of the catalyst doped oxide and composite support to replace the carbon support,so as to improve the electrochemical durability of the catalyst.Firstly,the vanadium phosphate containing carbon was prepared by hydrothermal synthesis method.It was a carrier and chloroplatinic acid was precursor,which reduced by rethylene glycol for preparing vanadyl phosphate doped carbon carrier supported Pt catalyst?Pt/C-VO?H₂PO₄?₂?.CV test and transmission electron microscopy and other electrochemical and physical and chemical characterization tests show that the Pt of Pt/C-VO?H₂PO₄?₂catalyst has a good dispersion and good electrochemical performance.The best doping amount of vanadium phosphate of Pt/C-VO?H₂PO₄?₂ catalyst was 6%.By the eight hundred cycle life test,the ESA decreased from 88%to 48%,and the durability was improved obviously.Single cell test showed that the electrochemical performance of the catalyst was maintained after the doping of vanadium phosphate.Carbon supported would experience corrosion under the operating environment in the laboratory,high voltage is 1.2V?vs.SCE?.The VO₂⁺/VO²⁺ redox of preferential oxidation of the vanadium phosphate,so the preferential oxidation of vanadyl phosphate prevented the oxidation of the carbon support and slowed down corrosion of carbon carrier.Secondly,using the constant temperature magnetic stirring method,TiN-TiO₂ composite conductive catalyst support was prepared by using nano titanium nitride as precursor.BET specific surface area test results show that the temperature is the maximum,surface area value is 111 m2·g-1 under the conditions that temperature was 80 ?,reaction time was 2.5 h and the concentration of sodium hydroxide solution was 0.5 M.The TiN-TiO₂ composite carrier is shown as lamellar or needle structure under scanning and projection electron microscope.Compared with the carbon carrier,the CV curve of the composite carrier has smaller corrosion current and better carrier performance after the constant potential corrosion.Platinum dispersion of composite support is still uniform.After the eight hundred cycle life test,the ESA decay rate is reduced from 82%to 62%.The electrochemical durability of the catalyst prepared by the composite support is improved than that of the Pt/C catalyst.