Enhanced CH3OH selectivity in CO2 hydrogenation using Cu-based catalysts generated via SOMC from GaIII single-sites.

ABSTRACT

Small and narrowly distributed nanoparticles of copper alloyed with gallium supported on silica containing residual GaIII sites can be obtained via surface organometallic chemistry in a two-step process (i) formation of isolated GaIII surface sites on SiO2 and (ii) subsequent grafting of a CuI precursor, [Cu(O t Bu)]4, followed by a treatment under H2 to generate CuGa x alloys. This material is highly active and selective for CO2 hydrogenation 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 infrared and solid-state nuclear magnetic resonance spectroscopy.