Quantum-chemical study of CO2 adsorption and dissociation on the W3O x/Cu(111) inverse catalyst

Abstract

Density functional calculations with dispersion correction (DFT-D3) have been performed to study the CO₂ adsorption and dissociation on W₃O_x/Cu(111) inverse catalyst (x = 9 or 6). The W₃O₉ aggregate adsorbs in several different geometries through the formation of O—Cu bonds, in all cases taking electronic charge from the metal surface. The reduced W₃O₆ particle anchors very strongly to Cu(111) by means of W—Cu bonds; in this case, the charge transfer is opposite to W₃O₉/Cu(111), yielding the oxide particle positively charged. CO₂ is activated on W₃O₉/Cu(111) only in the form that is by far the least stable (the one possessing Cs symmetry). In contrast, CO₂ is activated on W₃O₆/Cu(111) at the oxide metal interface; its dissociation was found to be exothermic and kinetically favorable than on the pure counterparts, Cu(111) and WO₃(001) surfaces. Our results suggest that stoichiometry and symmetry of Cu-supported W₃O_x clusters play a crucial role in CO₂ activation and dissociation.