Capping agent free synthesis of PtSn bimetallic nanoparticles with enhanced electrocatalytic activity and lifetime over methanol oxidation

PtSn bimetallic nanoparticles have been prepared by a hydrothermal method. [PtCl2(SnCl3)2]2− complex is used as precursor and no capping agent is used. XRD and TEM show the formation of PtSn nanocrystals with average sizes of 2 nm. The PtSn bimetallic nanoparticles show enhanced electrocatalytic activity and lifetime for the electrooxidation of methanol compared with that at Pt nanoclusters. The peak potential for the oxidation of methanol is 0.69 V (vs. SCE) for PtSn nanparticles, which is 20 mV more negative than that of Pt nanoclusters (0.71 V vs. SCE). Peak current density of PtSn nanoparticles is 2.75 mA/cm2, which is 28% higher than that of Pt nanoclusters (2.14 mA/cm2). The catalytic lifetime of PtSn nanoparticles is 4 times that of Pt nanoclusters.