Studies On The Synthesis Of Graphene-TiO₂ Composites Carrier And Its Catalytic Performance

Proton exchange membrane fuel cells have extensive commercial prospect in the future for its advantages of cleanliness,high efficiency,portability and low start-up temperature.Electrocatalysts,as key materials,whose activity and stability are crucial for the performance and lifetime of fuel cell.Microwave assisted method is beneficial to prepare catalysts with small size and high dispersion because of its advantages,such as quick reaction and heating process,energy saving and cleanliness.In this dissertation,the structure,electrocatalytic activity,and stability of Pt/graphene-TiO₂ catalyst were investigated by modern spectroscopic techniques and electrochemical methods.And the main results are as follows:（1）Graphene oxide was prepared by modified Hummer’s method,and was reduced by microwave assisted method.The surface area of graphene is 388.37 m2/g.（2）TiO₂ was acquired by microwave assisted method.The results showed that the cubic anatase TiO₂ is small particle size and high crystallinity.At low temperature,the crystallization of TiO₂ is not complete,but at high temperature,the crystal nucleus of TiO₂ gathers together to form irregular shape.（3）The composites were synthsised by mechanochemical method and microwave assisted method.The results demonstrate that the samples prepared with mechanochemical method exhibited better characteristics.（4）Pt/graphene-TiO₂ catalyst is prepared by microwave assisted method.The TiO₂ was uniformly dispersed on the lamellar structure of graphene.The Pt particles were dispersed uniformly on the composite carrier,and the particle size distribution was uniform,which was about 2.5 nm.The stability of the catalyst is higher than Pt/C catalyst.When the content of TiO₂ is 20 wt.%,the catalyst achieves the best comprehensive performance.