Enhanced CH3OH Selectivity in CO2Hydrogenation using Cu-based Catalysts Generated via SOMC from GaIIISingle-Sites

Small and narrowly distributed nanoparticles of copper alloyed with gallium supported on silica containing residual GaIIIsites can be obtained via surface organometallic chemistry in a two-step process: i) formation of isolated GaIIIsurface sites on SiO2and ii) subsequent grafting of a CuIprecursor, [Cu(OtBu)]4, followed by a treatment under H2to generate CuGaxalloys. This material is highly active and selective for CO2hydrogenation to CH3OH. In situ X-ray absorption spectroscopy shows that gallium is oxidized under reaction conditions while copper remains as Cu0. This CuGa material only stabilizes methoxy surface species while no formate is detected according to ex situ IR and solid-state NMR spectroscopy