CO2Activation on Cu/TiO2Nanostructures: Importance of Dual Binding Site

Abstract

AbstractCO2adsorption and activation on Cu single atom catalysts and Cu nanoclusters supported on the (110) surface of rutile and on the (101) surface of anatase TiO2have been investigated by means of first principles electronic structure calculations. The role of oxide reduction associated to the presence of oxygen vacancies has been considered. Five main messages emerge from this study. (1) CO2activation on Cu/TiO2nanostructures is surface sensitive, as the rutile and anatase surfaces can exhibit different behaviors; (2) the surface morphology is essential since CO2is activated only when the molecule can simultaneously bind to at least two active sites, such as a Cu atom on one side and an oxide ion on the other site; (3) Cu atoms on TiO2are in the +I oxidation state and can bind and activate CO2via charge transfer from the oxide; (4) on supported Cu clusters CO2activation occurs mostly at the metal/oxide interface; (5) the presence of O vacancy sites facilitates the spontaneous dissociation of CO2to CO, or increases the electron density of the metal catalyst, two effects that can influence the mechanism of CO2reduction to methanol or other chemicals.