Investigating the Plasmon-Mediated Catalytic Activity of AgAu Nanoparticles as a Function of Composition: Are Two Metals Better than One?

The surface plasmon resonance (SPR) excitation by visible light in plasmonic nanostructures can be put to work to mediate catalytic processes. However, the role of composition in bimetallic nanoparticles over the SPR-mediated catalytic activity remains unclear. We investigated herein the SPR-mediated catalytic activity of AgAu nanoparticles as a function of composition toward the oxidation of p-aminothiophenol to p,p′-dimercaptoazobenzene. Our results showed that a "volcano-type" relationship between composition and product conversion was observed, with a maximum activity observed for Ag0.19Au0.81 nanoparticles. The variations in catalytic activity could be explained by the balance between the matching of the excitation wavelength with SPR position and the plasmonic damping due to interband transitions above 500 nm. These data suggest that the precise control over composition allows the fine-tuning of catalytic activity in SPR-mediated catalytic processes.