Titanium Oxide Nanosheet Modified PtRu/C Electrocatalyst for Direct Methanol Fuel Cell Anodes

Abstract

Composite catalysts consisting of conventional PtRu/C electrocatalysts and TiO2 nanosheets (TiO2ns−PtRu/C) were prepared to explore the effect of nanostructured titanium dioxides as additives toward the electrooxidation of methanol and preadsorbed CO. An increase in the electrochemically active PtRu surface area and methanol oxidation activity was observed for a composite catalyst with a low TiO2ns content, whereas composites with a high content tended to have a lower catalytic activity compared with pristine PtRu/C. After conducting accelerated degradation tests by potential cycling between 50 and 800 mV versus RHE at 60 °C, almost all of the activity of the unmodified PtRu/C catalyst was lost. In contrast, methanol oxidation was still observed after potential cycling for the composite catalysts, with the best catalyst exhibiting an almost 10-fold higher activity compared with PtRu/C. The enhanced durability of the catalyst is discussed based on the ability of the TiO2 nanosheet to suppress the Ru loss from the catalyst.