Density Functional Theory Calculation of Electronic Structure of Fe-N-C, Fe-O-C, Fe-P-C, Fe-S-C Single-atom Catalysts Systems

Abstract

Single atom catalysts (SACs) have emerged as a novel class of heterogeneous catalysts which exhibit superior catalytic performance in various reaction, CO oxidation, CO2 conversion, oxygen reduction reaction (ORR), etc. It is challenging to explore electronic structure and catalytic mechanics of SACs when the single metal atom is bonding with different dopants via experimental methods, which influence the catalytic efficiency directly. In this paper, Density Functional Theory (DFT) calculations, an ab initio simulation methods, have been carried out to investigate the properties of Fe-N-C, Fe-O-C, Fe-P-C, and Fe-S-C with oxo or hydroxyl group, four common SACs models. Geometry structure of Fe-N-C, Fe-O-C, Fe-P-C, Fe-S-C, and after each has bonded with oxo or hydroxyl group are studied. Formation energy of the Single Atom Catalyst (SAC), oxygen formation energy, and hydrogen atom transfer energy of the four SACs models are also calculated. In order to investigate the electronic structure of the four SACs, we examined the HOMO LUMO gap values for each system. In addition, we plotted the corresponding HOMO and LUMO orbitals of each SACs models and with oxo or hydroxyl group. Through analyzing the data, I anticipated that Fe-N-C model is the easiest to synthesis and the most stable among the four models. Our work discloses the microscopic property of SACs and provides valuable suggestions to experimental scientists.