Effect of alloying degree in PtSn catalyst on the catalytic behavior for ethanol electro-oxidation

Carbon-supported binary PtSn catalysts with varied alloying degree were synthesized in different Processes and denoted as PtSn/C-B, PtSn/C-EG and PtSnO2/C, respectively. X-ray diffraction (XRD) characterizations showed that PtSn/C-B catalyst displayed the highest alloying degree, while PtSnO2/C Catalyst had the lowest one among these samples. X-ray photoelectron spectroscopy (XPS) results revealed that the non-alloyed Sn existed in an oxidized state on the surfaces of these catalysts. By evaluating the electrocatalytic activity and analyzing the final products of ethanol oxidation reaction (EOR) on these catalysts, it was found that PtSnO2/C catalyst enhanced the products yield of acetic acid products and PtSn/C-B catalyst promoted the entire activity for EOR. It was proposed that non-alloyed SnO2 species enhanced the bi-functional mechanism, whereas PtSn alloy phase strengthened the electronic effect of PtSn/C catalyst. (C) 2008 Elsevier Ltd. All rights reserved.