Au/LaVO₄ Nanocomposite: Preparation, Characterization, and Catalytic Activity for CO Oxidation

The size of the gold particles is a very important parameter to get active catalysts. This paper reports a novel colloidal deposition method to prepare Au/LaVO₄ nanocomposite catalyst with monodispersed Au colloids and uniform LaVO₄ nanoplates in nonpolar solvent. Monodispersed Au colloids with tunable size (such as 2, 5, 7, 11, 13, and 16 nm) and LaVO₄ nanocrystals with well-defined shapes were pre-synthesized assisted with oleic acid/amine. During the following immobilization process, the particle size and shape of Au and LaVO₄ were nearly preserved. As-prepared Au/LaVO₄ nanocomposite showed high catalytic activity for CO oxidation at room temperature. Since sizes of gold particles were well-defined before the immobilization process, size effect of gold particles was easy to be investigated and the results show that 5-nm Au/LaVO₄ nanocomposite has the highest activity for CO oxidation. This synthetic method can be extended further for the preparation of other composite nanomaterials.