DRIFTS-SSITKA-MS investigations on the mechanism of plasmon preferentially enhanced CO2 hydrogenation over Au/γ-Al2O3

Abstract

The localized plasmon resonance (LSPR) is recognized as an effective way to convert incident light energy and significantly boost the catalytic reaction. However, a comprehensive understanding of the plasmon-thermo coupling mechanism is still lacking. To address this knowledge gap, we investigate reaction pathway and plasmonic enhancement mechanism of the photo-thermo coupled catalytic reverse water gas shift (RWGS) reactions over Au/γ-Al2O3. The results indicate that both formate and carboxyl pathways contribute to the overall reaction. The m-formate pathway is suggested as the main reaction mechanism at low reaction temperature over small Au NPs. Spectro-kinetics and theoretical calculation analyses indicate that the plasmonic energy preferentially transfers to HCOO* via a combination of hot electron and resonance energy transfer mechanisms. The plasmonic energy facilitates the dehydration of HCOO* to CO, which is the rate-determining step (RDS) of the overall RWGS reaction.