Insights into SO2 and H2O co-adsorption on Cu (100) surface with calculations of density functional theory

The co-adsorption behaviors of SO2 and H2O on face-centered cubic Cu (100) ideal surface were studied using the GGA-rPBE method of density functional theory (DFT) with slab models. The optimized structures of single H2O and SO2 on Cu (100) surface were calculated at the coverage of 0.25 ML (molecular layer) and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu (100) surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states (PDOS) of co-adsorbed structures of H2O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML.