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

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 (V_deposition) of Ag is much more sensitive to the temperature, compared to the surface diffusion rate (V_diffusion) which can be effectively reduced by the binding of poly(vinylpyrrolidone) (PVP) molecules. Then the magnitude of V_deposition/V_diffusion 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.