Photothermal CO2 hydrogenation to methanol over a CoO/Co/TiO2 catalyst in aqueous media under atmospheric pressure

Catalytic conversion of CO2 into methanol is of particular interest as it does not only provide valuable methanol, but also utilize the waste CO2. In the present work, a CoO/Co/TiO2 catalyst was developed and utilized in catalyzing CO2 to methanol under photothermal conditions. From the results of characterization, the supported Co nanoparticles (NPs) were composed of Co0 in the bulk, CoO film formed from air oxidation on the surface, and Co0 at Co NPs-TiO2 interfaces. This structure provided the possibility for a Z scheme photothermal catalytic system, which revealed a high activity for methanol formation in aqueous media under atmosphere pressure. It was proposed that the light excited electrons from the valence band (VB) of TiO2, and the excited electrons could enhance the Co0 catalytic activity under thermal conditions. The present approach will offer a new strategy to design Co based Z scheme catalysts and further improve the conversion efficiency from CO2 to fuels.