| Summary: | Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO<sub>2</sub> hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu<sup>0</sup> as a crystal core. These effects are advantageous to H<sub>2</sub> dissociative adsorption and CO<sub>2</sub> activation, giving a high CO<sub>2</sub> conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H<sub>2</sub> dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C<sub>2</sub><sup>+</sup> hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO<sub>2</sub> conversion and C<sub>2</sub><sup>+</sup> selectivity of 52.87 mol% and 89.70 mol%, respectively.
|
|---|