Synergistic Effect of Copper and Indium Species for\nHighly Selective CO<sub>2</sub> Hydrogenation to Methanol

CO<sub>2</sub> hydrogenation to methanol over Cu-based catalysts\nfaces challenges such as low methanol selectivity and poor stability.\nHere, we report a series of CuIn bimetallic catalysts with different\nCu/In ratios prepared by the coprecipitation method. Among them, the\nmethanol selectivity of Cu<sub>25</sub>In<sub>75</sub> reaches as\nhigh as 92.5% at 200 °C and 64.5% at 260 °C, which is 1.3\ntimes and 1.9 times higher than that of the commercial catalyst at\n200 and 260 °C, respectively. Moreover, Cu<sub>25</sub>In<sub>75</sub> exhibits high stability for 200 h time-on-stream at 260\n°C. The high selectivity originates from a strong interaction\nbetween Cu species and In<sub>2</sub>O<sub>3–<i>x</i></sub> with oxygen vacancies. On the interface between Cu and In<sub>2</sub>O<sub>3–<i>x</i></sub>, dispersed Cu is the\nmain contributor to the activation and dissociation of H<sub>2</sub>, while the oxygen vacancies in In<sub>2</sub>O<sub>3</sub> adsorb\nand activate CO<sub>2</sub>. During the reaction, the abundance of\nhydrogen facilitates the reduction of the In<sub>2</sub>O<sub>3</sub> surface, promoting the generation of surface oxygen vacancies and\nproviding the necessary hydrogen for the hydrogenation reaction. Our\nresearch unveils a promising synergistic strategy for the rational\ndesign and application of Cu-based catalysts in CO<sub>2</sub> hydrogenation,\noffering avenues for further exploration and advancement in this field.