In situDRIFTS examining the impact of indium doping on activity of CuIn/ZrO2 catalyst for CO2 hydrogenation to methanol

Abstract

AbstractWe describe the synthesis of CuIn/ZrO2 catalysts via a facile mechanochemical synthesis method. In doping was demonstrated to promote the formation of strong Cu–In2O3 interactions and increase the number of Cu+ sites. The CuIn0.05/ZrO2 catalyst shows relatively high selectivity and space–time yield of methanol (~50% and ~1.25 , respectively) at 300°C and 5 MPa, outperforming those of the Cu/ZrO2 catalyst (~25% and ~1.12 , respectively). Time‐resolved in situ DRIFTS results acquired under various reaction conditions (typically H2/D2 isotope exchange) demonstrate that the surface Cu+–bound formate was the most reactive intermediate and the subsequent hydrogenation process should be the rate‐limiting step, which was positively promoted by the inclusion of In. The strong Cu–In2O3 interaction promotes a decrease in Cu0 sites, leading to a weak interaction of the Cu0‐bound CO intermediates, thus facilitating further hydrogenation of these species rather than releasing CO product.