Interface-Controlled Pd Nanodot-Au Nanoparticle Colloids for Efficient Visible-Light-Induced Photocatalytic Suzuki-Miyaura Coupling Reaction

Abstract

Plasmonic nanostructures can be employed for performing photocatalytic reactions with visible-light illumination involving two different possible mechanisms, namely, the near-field enhancement and/or direct hot-electron transfer to the conduction band of an active catalyst. In this study, we demonstrate the significant contribution of a graphene interface layer present between plasmonic nanoparticles and active catalysts (Pd nanodots) in enhancing the photocatalytic efficiency of Pd nanodots through an accelerated electron transfer process. The well-defined Pd-nanodot-modified gold nanoparticles with or without a graphene interface layer were prepared using a wet-chemical synthetic method. The role of the graphene interface was investigated by performing wavelength-dependent reduction studies using potassium hexacyanoferrate (III) in the presence of Pd-nanodot-modified cysteamine-modified AuNPs (Pd-cys-AuNPs), Pd-nanodot-modified graphene oxide (GO)-coated AuNPs (Pd-GO-AuNPs), and Pd-nanodot-modified reduced GO (rGO)-coated AuNPs (Pd-rGO-AuNPs). The fastest rate for the reduction of Fe3+ to Fe2+ was obtained with Pd-rGO-AuNPs because of the fast electron transfer achieved in the presence of the reduced graphene oxide layer. The highest catalytic activity for the visible-light induced C-C coupling reaction was obtained with Pd-rGO-AuNPs, indicating the role of the graphene interface layer. These results indicate that the design and use of engineered interfaces are of importance to achieve enhanced catalytic activity with plasmonic hybrid nanomaterials.