Effect of Composition and Surface Type on Activity of Transition Metal Oxides and Sulfides for CO2 Electrochemical Reduction

Abstract

Transition metal oxides (TMO) and transition metal sulfides (TMS) are proven to be promising electrocatalysts for CO2RR but there is no clear understanding on catalyst activity or product selectivity based on trends in binding free energies. Therefore, a broader array of TMO and TMS are studied as electrocatalysts for CO2RR thus addressing the gap in this field. This work shows how different types of surface facets with same catalyst composition can fine-tune the binding free energies of intermediate species by modifying the active binding site. Here, catalyst activity for CO2RR towards formation of 4 different products is computed and compared for different materials with (100), (110) and (111) crystal facets and based on this, product selectivity is determined. Optimal catalyst design strategies for this family of materials are developed using the binding free energies of 4 key intermediate species COOH*, CO*, HCO* and H*. In this study, among the materials studied, ZnO zincblende (100) is the material that showed highest catalyst activity towards CO2RR to CH3OH and CH4 while minimizing HER<br>