Controlling CO2 hydrogenation selectivity by metal-support electron transfer under reaction conditions.

Tuning CO 2 hydrogenation selectivity to obtain targeted value-added chemicals and fuels has attracted great yet ever-increasing attention. However, a fundamental understanding of the nature to control the selectivity is still lacking, posing a challenge in catalyst design and development. Here, we report our new discovery in ambient pressure CO 2 hydrogenation reaction where selectivity can be completely reversed by simply changing the crystal phases of TiO 2 support (anatase - or rutile-TiO 2 ) or changing metal loadings on anatase-TiO 2 . Operando spectroscopy and NAP-XPS studies reveal the determining factor is electron transfer from metal to support under reaction conditions most probably caused by hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO 2 hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design.