Catalytic activity of V2CO2 MXene supported transition metal single atoms for oxygen reduction and hydrogen oxidation reactions: A density functional theory calculation study

Two-dimensional (2D) MXene and single-atom (SA) catalysts are two frontier research fields in catalysis. 2D materials with unique geometric and electronic structures can modulate the catalytic performance of supported SAs, which, in turn, affect the intrinsic activity of 2D materials. Density functional theory calculations were used to systematically explore the potential of O-terminated V2C MXene (V2CO2)-supported transition metal (TM) SAs, including a series of 3d, 4d, and 5d metals, as oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) catalysts. The combination of TM SAs and V2CO2 changes their electronic structure and enriches the active sites, and consequently regulates the intermediate adsorption energy and catalytic activity for ORR and HOR. Among the investigated TM-V2CO2 models, Sc-, Mn-, Rh-, and Pt-V2CO2 showed high ORR activity, while Sc-, Ti-, V-, Cr-, and Mn-V2CO2 exhibited high HOR activity. Specifically, Mn- and Sc-V2CO2 are expected to serve as highly efficient and cost-effective bifunctional catalysts for fuel cells because of their high catalytic activity and stability. This work provides theoretical guidance for the rational design of efficient ORR and HOR bifunctional catalysts. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.