Intrinsic insight on localized surface plasmon resonance enhanced methanol electro-oxidation over a Au@AgPt hollow urchin-like nanostructure

Abstract

The plasmon effect on the catalytic performance of metal nanoparticles (NPs) has shown great potential for the design of novel catalytic reactions. However, the intrinsic mechanisms underlying the catalysis triggered by localized surface plasmon resonance (LSPR) are still ambiguous. In this work, we construct Au@AgPt hollow urchin-like structures (Au@AgPt HUSs) with an ultra-thin Pt shell for the electrocatalytic methanol oxidation reaction (MOR) in an alkaline solution under irradiation (200 mW cm_m⁻²). A superior MOR mass activity (3.26 A mg⁻¹ Pt) is achieved on Au@AgPt HUSs, which is 5.43 times that of commercial Pt black catalysts (0.6 A mg⁻¹ Pt) under irradiation. It is also reported that localized heating, which results from the photothermal effect under irradiation, can accelerate the reaction kinetics of MOR over Au@AgPt HUSs. Theoretical calculations demonstrate that the reduced lowest unoccupied molecular orbital (LUMO) energy level of CO induced by the localized electric field can accelerate the rate-determining step *CO to *COOH, and the energetic hot carriers provide energy to promote the transfer of *CO from the hollow Pt site to the top Pt site. Thus, the hollow Pt active sites poisoned by *CO can be reactivated due to the *CO transfer mechanism, leading to more available active sites for the MOR process. This work reveals the intrinsic effect of LSPR on catalysis and paves the way to boost conventional catalytic reactions by introducing solar energy flux.