Adjustable photocatalytic ability of monolayer g-C3N4 utilizing single–metal atom: Density functional theory

Abstract

Single–atom catalysis is an effective method to improve the catalytic efficiency. With the aid of density functional theory calculations, we investigated the thermodynamic performances during water splitting besides the structural and electronic performances of monolayer g–C3N4 embedded with single Ni, Pd, Pt, Cu, Ag or Au atom. Based on the detailed analysis of the electronic redistributions and chemical bond relaxations, the ratio of ionic and covalent bonding parts of chemical bonds were adjusted by the single atoms, it changed the adsorption energy of intermediates, the free energy changes during reaction and then the overpotentials of oxidation evolution reaction (OER) and hydrogen evolution reaction (HER). Interestingly, the overpotentials of OER and HER reduce as the percentage of covalent bonding parts is close to a certain value, which are conductive to improve the OER and HER efficiency. In addition, the differences of redox potentials between catalysts and water oxidation/H+ reduction are larger than the corresponding overpotentials of OER and HER on Pd1/ and Pt1/g–C3N4, thus the OER and HER can happen on them.