Preparation Improvement And Electrocatalytic Activity Of Pt/WC@TiO₂ Composites

Direct methanol fuel cells(DMFCs)are promising power sources for various applications.At present,platinum(Pt)is still the most commonly and effectively used anode material.Unfortunately,Pt is a rare and noble metal.Tungsten carbide(WC)is a new non-noble metal catalyst material and has been considered as a promising catalyst due to its high resistance to CO and H2S,excellent acid and alkali resistance and lower price.However,the catalytic property of WC is less than that of platinum metal.In order to improve the catalytic property,we prepare a kind of core-shell Pt/WC@Ti02 catalyst.After careful observation,we think that special core-shell structure can improve the catalytic property efficiently.In this work,Pt/Ti02,Pt/WC/TiO2 and Pt/WC@TiO2 composite catalysts were prepared firstly.Then the composites were characterized by XRD,SEM and TEM methods.Subsequently,the electrocatalytical activities of three composites for oxidation of methanol were investigated by cyclic voltammetry.It was found that the Pt/WC@TiO2 catalyst had the best electrocatalytic activity and stability.Based on this,we optimize the preparing condition,including different kinds of TiO2,different carbonization condition of WC and different ratio of Ti02 andWC.Furthermore,since the electrical conductivity of Pt/WC@Ti02 is not good enough,we prepared 3D structure Pt/WC/BCs catalyst and the catalyst was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).In the further electrochemical investigation,it was found that Pt/WC/BCs catalyst had a higher methanol oxidation performance and better CO-tolerance compared with Pt/WC/CNTs and commercial Pt/C.