Study On The Preparation And Performance Of Functional PEMFC Catalyst

Fuel cell is a device that can convert the chemical energy of fuel into electrical energy through electrochemical reaction.As a key component of fuel cell,the membrane electrode consists of catalytic layer,gas diffusion layer and a proton exchange membrane.Among them,the corrosion of Pt/C catalyst on C-support at high potential seriously affects the stability and durability of the fuel cell.At the same time,the oxygen-containing free radicals produced in the reaction process have a serious impact on the dissolution of Nafion membrane and the performance of membrane electrode.In recent years,the research of fuel cell catalysts focuses on finding a high activity and long-lasting ORR catalyst.Metal oxides have great advantages in resisting high potential corrosion and anti-oxygen-containing free radicals.Meanwhile,the strong interaction between metal oxides and Pt is beneficial to improve the stability of the catalyst.In this paper,the high potential corrosion of PEMFC commercial catalyst and the generation of free radicals in the reaction process were studied.The scheme of preparing Pt/CeO2 Pt/SiO2 catalyst with oxide(CeO2?SiO2)as support by LBL method was proposed.The structure and morphology of the catalyst were characterized by XRD and TEM.The electrochemical properties and durability of the catalyst were studied,and some results were obtained.The main conclusions are as follows:(1)Pt/CeO2 catalyst was prepared by LBL method.The particle size of Pt on the sample surface is 2-4 nm.The temperature of heat treatment has a great influence on the particle size of Pt.The particle size will grow up obviously after heat treatment at 300? or above and in N2 atmosphere for 2 h.(2)Pt/CeO2-60-300 catalyst prepared with CTAB as surfactant and heat-treated in N2 for 2h showed good electrochemical performance.The mass specific activity of 0.9 V was 41.8 mA·mgPt-1,and the ECSA was 12.2 m2·gPt-1,but it was lower than 237 mA·mgPt-1 and 37.9 m2·gPt-1 of Johnson Matthey Pt/C catalyst.The high resistance of CeO2 is the key to hinder the further improvement of catalyst performance.(3)The catalyst prepared with CeO2 as support has good stability in high potential circulation,and almost no change in 10000 cycles durability test 1.0-1.5 V.The strong interaction between Pt and CeO2 is an important factor to improve the stability of the catalyst.