Dual-site activation of H2 over Cu/ZnAl2O4 boosting CO2 hydrogenation to methanol

Methanol synthesis derived from CO2 hydrogenation has attracted great attention in terms of CO2 recycling while suffering from the low activity and sintering of copper species. Herein, we unveil the remarkable activity (11.3%) and methanol STY (242 gCH3OH kgcat−1 h−1) of 8 wt% Cu/ZnAl2O4 at 220 °C and 3 MPa, far surpassing that of conventional 8 wt% Cu/ZnO/Al2O3 composite oxides (6.8% for CO2 conversion and 144 gCH3OH kgcat−1 h−1 for methanol STY). The brilliant capability of H2 dissociation over Cu/ZnAl2O4 promotes methanol production due to the strong metal-support interaction. In-depth characterization points that the interstitial H atoms in ZnAl2O4 support contribute to the generation of the formate species, whose hydrogenation to methanol is participated by the H atoms dissociated from Cu nanoparticles. Dual-site activation of H2 allows an acceleration of methanol synthesis. This work offers a new avenue to modify catalyst structure for effectual CO2 hydrogenation under moderate conditions.