Performance of platinum nanoparticles supported on hollow mesoporous tungsten trioxide microsphere as an electrocatalyst for methanol oxidation

Hollow dendritic mesoporous tungsten trioxide (d-WO₃) was synthesized by combining the hydrothermal method with the template-sacrificing method; with d-WO₃ as a support, Pt/d-WO₃ catalyst was prepared through an improved liquid phase reduction method. The Pt/d-WO₃ catalyst was characterized by XRD, BET and TEM and its electrocatalytic activity and stability towards methanol electro-oxidation were investigated by cyclic voltammetry and chronoamperometry. The results indicated that d-WO₃ exhibits hollow microsphere dendritic structure with a length of 6 μm and a width of 2 μm; Pt nanoparticles with a size of 7.2 nm were highly dispersed on the surface of d-WO₃. The nitrogen physisorption on d-WO₃ displays type IV isotherms, which are typical for the mesoporous materials. Moreover, d-WO₃ shows a BET surface area of 24 m²/g, with a large number of pores around 20~120 nm. The as-prepared Pt/d-WO₃ catalyst exhibits higher electrocatalytic activity and better stability in methanol electro-oxidation in comparison with the Pt/WO₃ and Pt/C catalysts. The enhanced catalytic performance of Pt/d-WO₃ is attributed to its unique hollow mesoporous structure and the double function, which greatly accelerates the dehydrogenation of methanol on Pt.