Controlling CO₂ Hydrogenation Selectivity by Metal-Supported Electron Transfer

Tuning CO₂ hydrogenation selectivity to obtain targeted value-added chemicals and fuels has attracted increasing attention. However, a fundamental understanding of the way to control the selectivity is still lacking, posing a challenge in catalyst design and development. Herein, we report our new discovery in ambient pressure CO₂ hydrogenation reaction where selectivity can be completely reversed by simply changing the crystal phases of TiO₂ support (anatase- or rutile-TiO₂) or changing metal loadings on anatase-TiO₂. Operando spectroscopy and NAP-XPS studies reveal that the determining factor is a different electron transfer from metal to the support, most probably as a result of the different extents of hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO₂ hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design.