Origin of the enhancement of electrocatalytic activity and durability of PtRu alloy prepared from a hetero binuclear Pt-Ru complex for methanol oxidation reactions

大川 侑久*; 増田 卓也*; 上原 広充*; 松村 大樹; 田村 和久; 西畑 保雄; 魚崎 浩平*

RSC Advances (Internet), 3(35), p.15094 - 15101, 2013/09

https://doi.org/10.1039/c3ra42816h

PtRu alloy, prepared by pyrolysis of hetero bi-nuclear PtRu complexes, showed a higher electrocatalytic activity and durability in the methanol oxidation reaction than PtRu alloy prepared by pyrolysis. The origin of this activity enhancement was investigated by XPS and Ru K edge XAFS measurements. Although both alloys were composed of metallic Pt and Ru oxide, the Ru oxide in the PtRu alloy prepared from the PtRu complex had greater oxygen deficiency than that in the PtRu alloy. XAFS measurements showed that the RuO distance of the former was longer than that of the latter, suggesting the presence of the weakly coordinated oxygen species, water, in the PtRu alloy prepared from the PtRu complex. The water coordinated to Ru can become an active oxidant, surface RuOH, under electrochemical conditions and enhance MOR activity and durability.