CeO₂-modified α-MoO₃ nanorods as a synergistic support for Pt nanoparticles with enhanced CO_ads tolerance during methanol oxidation

A new type of Ce-doped α-MoO₃ (Ce_0.2Mo_0.8O_3-δ) nanorod support was synthesized using a two-step hydrothermal method. The mixed oxide solid solution was employed as a novel non-carbon support for Pt catalysts used for the methanol electrooxidation in acidic media. The ratio of Ce to Mo in the solid-solution was systematically optimized in terms of the performance as a support for methanol oxidation. Pt nanoparticles with an average diameter of 2 nm were evenly deposited on Ce_0.2Mo_0.8O_3-δ nanorods. Compared to the Pt/MoO₃ and commercial Pt/C catalysts, the optimal Pt/Ce_0.2Mo_0.8O_3-δ catalyst exhibited significantly enhanced CO_ads tolerance during the methanol oxidation, thereby yielding the highest electrocatalytic activity and stability. The improved electrochemical performance can be ascribed to strengthened metal-support interactions derived from the high number of oxygen vacancies on Ce_0.2Mo_0.8O_3-δ along with its unique one-dimensional nanorod structure. In addition, these findings suggest that the doping-induced structural and size transition of MoO₃ could provide a new pathway to develop doped oxides capable of providing sufficient electrical conductivity and possible synergistic effects with other active components for electrocatalysis applications.