Production of methanol from anthropogenic carbon dioxide (CO2) is a promising chemical process that can alleviate both the environmental burden and the dependence on fossil fuels. In catalytic CO2 hydrogenation...

Hydrogenation of carbon dioxide (CO 2 ) using CO 2 -free hydrogen (H 2 ) to produce methanol (CH 3 OH) is a promising reaction that can alleviate both carbon emissions and the dependence on fossil fuels. Nonstoichiometric molybdenum suboxide coupled with Pt nanoparticles (NPs) acts as a promising catalyst for this reaction, in which surface oxygen vacancies (V O ) and the redox ability of Mo in molybdenum suboxide are the keys to transforming CO 2 into the CO intermediate and further to afford CH 3 OH. In this study, a series of molybdenum oxides with different morphologies, including bulk, nanosheet, nanobelt, and rod morphologies, are used as catalysts, and the effects of particle morphologies on the catalytic performance toward CO 2 hydrogenation are examined. A Pt-loaded molybdenum suboxide nanosheet (Pt/ H x MoO 3−y (Sheet)) with a high specific surface area affords 1.35 times greater CO 2 conversion and CH 3 OH yield in liquid-phase CO 2 hydrogenation compared with the corresponding bulk analog under relatively mild reaction conditions (total 4.0 MPa, 200 °C). Experiments and comprehensive analyses, including X-ray diffraction and in situ X-ray absorption fine structure studies, reveal that the enhanced activity of Pt/H x MoO 3−y (Sheet) is attributable to a high concentration of surface-exposed V O sites, which are introduced in the (010) plane during the H 2 reduction due to the high surface-to-volume ratio of the nanosheet-structured MoO 3 . In addition, the nanosheet-structured catalyst exhibits better reusability because of its antiaggregation behavior for Pt NPs compared with the conventional bulk analog.