Catalytic reduction of SO₂ by CO over Pt_lAu _m(CO)_n: A first-principles investigation

The catalytic activities, to the reduction of SO₂ by CO, of clusters Pt_lAu_m (l + m = 2) with or without preadsorbing CO molecules are investigated using first-principles density functional theory. We find that the PtAu(CO)_n (n = 1-3) clusters show more excellent catalytic properties than either pure metallic catalysts. Preadsorption of CO to the catalysts could effectively avoid platinum-based catalyst sulfur poisoning; as more CO molecules preadsorbed to the catalysts, the energy barriers for the carbonyl sulfide (COS) molecules desorption from the catalyst are remarkably decreased. We propose an ideal catalytic cycle to simultaneously get rid of SO₂ and CO over the catalysts PtAu(CO)₃.