Two-dimensional molybdenum carbide 2D-Mo(2)C as a superior catalyst for CO(2) hydrogenation

Early transitional metal carbides are promising catalysts for hydrogenation of CO(2). Here, a two-dimensional (2D) multilayered 2D-Mo(2)C material is prepared from Mo(2)CT(x) of the MXene family. Surface termination groups T(x) (O, OH, and F) are reductively de-functionalized in Mo(2)CT(x) (500 °C, pure H(2)) avoiding the formation of a 3D carbide structure. CO(2) hydrogenation studies show that the activity and product selectivity (CO, CH(4), C(2)–C(5) alkanes, methanol, and dimethyl ether) of Mo(2)CT(x) and 2D-Mo(2)C are controlled by the surface coverage of T(x) groups that are tunable by the H(2) pretreatment conditions. 2D-Mo(2)C contains no T(x) groups and outperforms Mo(2)CT(x), β-Mo(2)C, or the industrial Cu-ZnO-Al(2)O(3) catalyst in CO(2) hydrogenation (evaluated by CO weight time yield at 430 °C and 1 bar). We show that the lack of surface termination groups drives the selectivity and activity of Mo-terminated carbidic surfaces in CO(2) hydrogenation.