Two-dimensional molybdenum carbide 2D-Mo2C as a superior catalyst for CO2 hydrogenation

Early transitional metal carbides are promising catalysts for hydrogenation of CO2. Here, a two-dimensional (2D) multilayered 2D-Mo2C material is prepared from Mo2CTx of the MXene family. Surface termination groups T-x (O, OH, and F) are reductively de-functionalized in Mo2CTx (500 degrees C, pure H-2) avoiding the formation of a 3D carbide structure. CO2 hydrogenation studies show that the activity and product selectivity (CO, CH4, C-2-C-5 alkanes, methanol, and dimethyl ether) of Mo2CTx and 2D-Mo2C are controlled by the surface coverage of T-x groups that are tunable by the H-2 pretreatment conditions. 2D-Mo2C contains no T-x groups and outperforms Mo2CTx, beta-Mo2C, or the industrial Cu-ZnO-Al2O3 catalyst in CO2 hydrogenation (evaluated by CO weight time yield at 430 degrees C and 1 bar). We show that the lack of surface termination groups drives the selectivity and activity of Mo-terminated carbidic surfaces in CO2 hydrogenation. The development of robust and efficient catalysts for CO2 hydrogenation to value-added chemicals is an urgent task. Here the authors report two-dimensional carbide catalyst based on earth-abundant molybdenum that hydrogenates CO2 with high activity, stable performance and tunable selectivity.

Automated summary

Early transitional metal carbides, such as 2D-Mo2C, show promising catalytic activity for CO2 hydrogenation through surface group manipulation, resulting in tunable selectivity and activity for the reaction. This study highlights the importance of surface termination groups in controlling the performance of carbide catalysts for CO2 conversion to value-added chemicals.