Solid-state interactions, adsorption sites and functionality of Cu-ZnO/ZrO2 catalysts in the CO2 hydrogenation to CH3OH

Abstract Structure, adsorption properties and surface reactivity of Cu-ZnO/ZrO 2 catalysts (ZrO 2 loading, 43 wt%; Zn/Cu (at/at), 0.0–2.8) have been probed by BET, XRD, TPR, N 2 O-titration, FTIR and TPD measurements of H 2 , CO and CO 2 . Characterization data indicate that ZnO promotes the dispersion and reactivity of metal copper to oxygen, while both ZnO and ZrO 2 support markedly enhance the surface CO 2 adsorption. A synergism of metal Cu hydrogenation and oxide basic sites discloses the primary role of the metal/oxide interface on the functionality of Cu-ZnO/ZrO 2 catalysts in the CO 2 to CH 3 OH hydrogenation reaction. The extent of the oxide/metal interface, probed both by Cu δ + /Cu 0 and oxide-to-metal surface area (OSA/MSA) ratios, provides a normalization of the Cu site specific activity (TOF) in a wide range (3–60%) of metal dispersion proving the dual-site nature and, then, the formal structure-insensitive character of the title reaction.