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

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.