Theoretical study of the local environment of Co-NxCy structure for selective oxidation of benzene to phenol

Abstract

Adjusting the local environment of single-atom catalysts (SACs) is a promising approach to enhance the catalytic performance in benzene oxidation reaction (BOR). Herein, a range of Co-based SACs with N2/3/4-coordination numbers on graphene were constructed to investigate the effect of the electronic structure of SACs on BOR via density function theory (DFT). Expectedly, the electron density and charge amount of the Co active sites in the overall reaction path on the CoNxCy catalyst can be regulated by coordination environment. In particular, the as-formed *O=CoN4=O* intermediate displays the strongest electron interaction between Co atom and O*, thus O* has the largest electron density and the most negative charge number, resulting in a lower energy barrier of 0.69 eV for the rate-determining step of CO bond formation. The methodology in this work provides a certain theory supporting and guidance for developing highly efficient SACs with controllable coordination structures to enhance hydrocarbon oxidation reactions.