DFT study on H2 and H adsorption and the electronic properties of single atom Cu modified Fe (1 1 1) surface

Abstract

Density functional theory was used to study the adsorption of H2 and H and electronic properties of single atom Cu modified Fe (1 1 1) including the Cu adsorption and substitution models. The adsorption ability of H2 and H on Cu modified Fe (1 1 1) could be weakened by the weak adsorption sites provided by Cu atom, Cu occupying the strong adsorption sites of Fe (1 1 1), and weak adsorption of H2 on Fe adjacent Cu, respectively. The analysis of electronic properties and crystal orbital Hamilton population of FeH bonds indicates that when Cu acts on Fe (1 1 1), the partial electrons of Fe can transfer to adjacent Cu, which weakens the bonding interaction between Fe and the adsorbed H2 and H and then weakens adsorption of Fe (1 1 1) as following: (1) the more electrons Cu atom obtains, the weaker it adsorbs H2 and H, (2) the more electrons Fe atom loses, the weaker it adsorbs H while there is an optimum charge point for H2. Therefore, the adsorption, dissociation of H2 and the catalytic activity of hydrogen-related reactions on Fe catalysts can be regulated by Cu modification, providing important information to further explore catalytic mechanism of syngas conversion reaction on Cu modified Fe catalysts.