Screwdriver-like Pd-Ag heterostructures formed via selective deposition of Ag on Pd nanowires as efficient photocatalysts for solvent-free aerobic oxidation of toluene

Abstract

Heterostructured bimetal nanocrystals with a component having localized surface plasmon resonance (LSPR) property are promising photocatalysts for a series of reactions. In this work, kinetic products of Pd-Ag with a screwdriver-like heterostructure have been successfully fabricated via the selective epitaxial growth of Ag on Pd nanowires (NWs). It was confirmed that the deposition rate (Vdeposition) of Ag is much more sensitive to the temperature, compared to the surface diffusion rate (Vdiffusion) which can be effectively reduced by the binding of poly(vinylpyrrolidone) (PVP) molecules. Then the magnitude of Vdeposition/Vdiffusion has been well tailored for the formation of a kinetic growth environment. The interactions between the components of the as-prepared Pd-Ag heterostructures resulted in intensified LSPR effects. As a result, they gained better photocatalytic performance toward solvent free aerobic oxidation of toluene than Pd NWs, Ag NWs and the mixture of them. Additionally, the Pd-Ag heterostructured nanocrystals exhibited excellent catalytic stability for recycling. This work not only presents an idea for realizing kinetic growth but also supports that LSPR effect is a good tool for improving the photocatalytic activity.