A general approach to noble metal-metal oxide dumbbell nanoparticles and their catalytic application for CO oxidation

Heterogeneous dumbbell-like nanoparticles represent an important type of composite nanomaterial that has attracted growing interest. Here we report a general approach to noble metal-metal oxide dumbbell nanoparticles based on seed-mediated growth. Metal oxides are grown over the presynthesized noble metal seeds by thermal decomposition of metal carbonyl followed by oxidation in air. The as-synthesized dumbbell nanoparticles have intrinsic epitaxial linkage between the metal and the oxide, providing enhanced heterojunction interactions. Moreover, the properties of one component are readily modified by the other in these nanoparticles, as demonstrated by the enhanced catalytic activity toward CO oxidation of such dumbbell nanoparticles in comparison with their counterparts prepared by conversional methods. The heterojunction effects provided in such nanostructures thus offer another degree of freedom for tailoring material properties. The developed synthetic strategy could also be generalized to other systems and thus represent a general approach to heterogeneous nanomaterials for various functional applications.