Real-Time Tracking the Electrochemical Synthesis of Au@Metal Core-Shell Nanoparticles toward Photo Enhanced Methanol Oxidation

Single particle plasmon scattering can provide real-time imaging information on the synthesis of nanomaterials. Here, an electrochemical deposition strategy is reported to synthesize plasmonic Au@Metal core-shell nanoparticles (Au@M NPs), which exhibit localized surface plasmon resonance (LSPR) properties. Because of the excellent catalytic activity of the methanol oxidation reaction (MOR), Pt, Pd, and Rh were reduced on the surface of Au NPs to form monometallic and bimetallic shells. Under dark field microscopy (DFM), the scattering changes could be utilized to track the surface nucleation and bulk deposition process. The synthesized Au@M NPs, which combined the plasmonic and electrocatalytic features, showed greatly enhanced activity for MOR. Under LSPR excitation, the electroxidation process toward MOR was accelerated and increased approximately linearly with increased illumination intensity, which could be mostly attributed to the generation of energetic charge carriers. This strategy of real-time plasmonic tracking electrochemical deposition at the single particle level is facile and universal, which could be extended to the precise synthesis of other plasmonic core-shell nanomaterials and the investigation of the pathway of plasmon accelerated chemical conversion.