V2o5-mwnt Nanocomposite as a Promising Support for Platinium in Methanol Electro - Oxidation

Introduction Direct methanol fuel cells are very important as a clean, low cost and portable power source because of several environmental problems in traditional energy producing systems. Compared to the hydrogen fueled PEMFCs, direct methanol PEMFCs are more compact and can be used in power portable electric devices. Platinum is the most active electro-catalyst for the electro-oxidation of methanol. However, pure platinum is a poor anode catalyst for methanol electro-oxidation at lower temperatures. This is because CO and various other carbonaceous intermediates are generated and block the active sites of the platinum catalyst during methanol electro-oxidation [1,2]. Making alloys with a second or a third metal is a convenient way to modify the electrocatalytic properties of platinum. Pt-Ru alloy is considered to be the best available anodic material for DMFCs [3]. Apart from Pt–Ru catalyst, materials like Pt–WO3, Pt–MoO3 and Pt– Ru–MOx (M =W, Mo and V) have been used as the electrode material for methanol oxidation [4-8]. One of the reasons for choosing these transition metal oxides is that these oxides form tungsten bronzes during dehydrogenation of methanol by effectively removing the hydrogen from the Pt surface. This helps to perform the dehydrogenation over Pt at lower over potentials. Also the oxophilic nature of the oxide helps in removing the strongly adsorbed reaction intermediates from the reaction site. In this study we proposed vanadium oxide / multi-wall carbon nanotube nanocomposite as a promising material for using as the support for Pt nanoparticles in methanol electro-oxidation.