Effects of coverage and solvent on H2S adsorption on the Cu(100) surface: A DFT study

Abstract

Density functional theory is used to investigate the effects of coverage and solvent on the adsorption of H2S on the Cu(100) surface. In this work, the adsorption energies, structural parameters and Mulliken charges of the adsorbed H2S are calculated. The results show that when the coverage of H2S is high (1 ML), H2S molecule cannot adsorb on the Cu(100) surface spontaneously, and the decomposition of H2S preferentially occurs at the bridge site. When the coverage decreases to 1/4 ML coverage, H2S molecule does not exhibit the decomposition, but bonds to the top Cu atom with the tilted adsorption. Furthermore, when the coverage is 1/9, 1/16 and 1/25 ML, H2S adsorption remains stable. In addition, the stability of H2S adsorption on the Cu(100) surface improves rapidly when the solvent dielectric constant (ε) increases from 1 to 12.3 corresponding to the vacuum and pyridine, respectively. For the higher ε (≥24.3), the effect of the solvent on the H2S adsorption was greatly reduced. In this work, both coverage and solvent are shown to have an important effect on the H2S adsorption on the Cu(100) surface, which might be useful to improve the future similar simulations. Copyright © 2015 John Wiley & Sons, Ltd.