CO2 hydrogenation on Cu-catalysts generated from ZnII single-sites: Enhanced CH3OH selectivity compared to Cu/ZnO/Al2O3

The hydrogenation of CO2 to CH3OH is mostly performed by a catalyst consisting mainly copper and zinc (Cu/ZnO/Al2O3). Here, Cu-Zn based catalysts are generated using surface organometallic chemistry (SOMC) starting from material isolated ZnII sites dispersed on SiO2 – ZnII@SiO2. Grafting [Cu(OtBu)]4 the silanols available ZnII@SiO2 followed reduction at 500 °C under H2 generates CuZnx alloy nanoparticles with remaining according X-ray absorption spectroscopy (XAS). This Cu-Zn/SiO2 displays high catalytic activity methanol selectivity, in particular higher conversion compared benchmark Cu/ZnO/Al2O3 most other catalysts. In situ XAS shows that partially converted into Cu(0) Zn(II) reaction conditions, while ex solid state nuclear magnetic resonance infrared spectroscopic studies only indicate presence methoxy species no formate intermediates detected, contrast Cu-based absence consistent selectivity as recently found for related Cu-Ga/SiO2.