Intermetallic Pt2Si: magnetron-sputtering preparation and electrocatalysis toward ethanol oxidation

Although most transition metals have been tested as the promoter to Pt for electrocatalysis toward fuel cell reactions, semi-conductor elements, such as Si, have hitherto not been examined. Here we report a simple synthesis of intermetallic (PtSi)-Si-2 electrode using magnetron sputtering and the electrocatalysis toward ethanol oxidation reaction (EOR). In comparison to Pt, the intermetallic Pt2Si surface turns out to be much more active in catalyzing the EOR: the onset potential shifts negatively by 150 mV, and the current density at 0.6 V increases by a magnitude of one order. Such an enormous enhancement in EOR catalysis is ascribed to the promotion effects of Si, which can not only provide active surface oxygenated species to accelerate the removal of COads, but also strongly alter the electronic property of Pt, as clearly indicated by the core-level shift in XPS spectrum.