Hybrid Electrocatalysts Composed of PtSn, Ru or PtRu Nanoparticles for Low-Temperature Oxidation of Dimethyl Ether Fuel

Abstract

Electrocatalytic activity of Vulcan-supported PtSn (PtSn/C) nanostructured alloys toward electrooxidation of dimethyl ether (DME), a potential small-organic-molecule fuel, has been significantly enhanced in acid medium (0.5 mol dm-3 H2SO4) by decorating PtSn/C with bimetallic PtRu nanoparticles modified with phosphododecatungstic acid (PtRu/PW12). The enhancement effect concerns both shifting the onset potential for the DME-oxidation toward less positive values and increase of the DME electrocatalytic current densities recorded under both cyclic voltammetric and chronoamperometric conditions. In that respect, the Ru-oxo species originating from PtRu additives seem to support activity of Sn co-catalytic sites interacting with Pt within the PtSn heterogenous alloy. The polytungstate adsorbates on nanoparticles facilitate their distribution at the electrocatalytic interface, as well as they interact competitively with the CO adsorbates at noble metal catalytic sites. The hybrid materials composed of PtSn/C decorated with PtRu nanoparticles modified with PW12 seem to act as multifunctional nanoreactors during electrooxidation of DME.