Metal/metal-oxide interface catalysed thermal and electrochemical CO2 conversion: a perspective from DFT-based studies

Abstract

Converting CO₂ to valuable chemicals through a variety of thermal, photo-, and electro-catalytic reaction processes will reduce the net CO₂ emission and contribute positively to the "net-zero" goal. C₁ and C₂ products are important chemical feedstocks and can be produced from the effective catalytic conversion of CO₂. The key to developing effective CO₂ conversion catalysts is an understanding of CO₂ interaction and the elementary bond-breaking and formation steps on the active catalysts. Over the past two decades, density functional theory-based approaches have enabled both mechanistic understanding and catalyst design for CO₂ activation and conversion. In this article, we review our recent effort in understanding the mechanism of CO₂ activation and conversion, focusing on the unique role of the metal/metal oxide interfaces in both thermal and electrochemical catalytic CO₂ reduction. We showed that In₂O₃-based catalysts exhibited a uniquely high methanol selectivity while suppressing CO formation from the reverse water-gas shift reaction. We have also demonstrated that the metal/metal-oxide interfaces can be tuned by selecting an appropriate metal and metal oxide to optimize its activity and selectivity for both thermal- and electro-catalytic reduction of CO₂. The oxophilicity of the metal in the metal oxide can be used as a qualitative measure for determining the selectivity towards CH₃OH or CH₄ in the electro-catalytic reduction of CO₂. The studies demonstrated the impact of the density functional theory-based atomic-level approaches in unravelling the reaction mechanism and predicting highly efficient catalysts and catalytic systems.