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.