Tuning the selectivity and activity of Au catalysts for carbon dioxide electroreduction via grain boundary engineering: a DFT study

Abstract

Au catalysts possess a high activity to yield gaseous carbon monoxide (CO) at moderate overpotentials for the carbon dioxide CO₂ electrochemical reduction reaction (CO₂RR). However, tuning selectivity remains a massive challenge towards the production of hydrocarbon species at relatively low potentials. In this study, by means of first principles calculations we propose a promising strategy to tune the selectivity and activity of Au catalysts via grain boundary (GB) engineering. The GB sites on the Au(110) surface are identified to strongly bind *CO so as to compensate for the unsaturated coordination of GB atoms, leading to a high selectivity toward CH₃OH; its catalytic performance is comparable to Cu for generating CH₄. In addition, GBs on the Au(100) surface are also investigated for comparison, which can greatly promote CO production. Our findings suggest that GB engineering is an effective means to improve the CO₂RR performance of a given catalyst, which will motivate reasonable design and synthesis of novel electrocatalysts for CO₂ reduction to produce hydrocarbon species.