Porous hollow structured CuIn bimetallic catalysts for CO2 hydrogenation to methanol

CO₂ hydrogenation to valuable chemicals such as methanol is an environmentally friendly and economically viable strategy, which is important for alleviating the energy crisis and achieving carbon neutrality goals. In₂O₃ catalysts are exciting due to their excellent methanol selectivity and catalytic stability. However, pure In₂O₃ or conventional structured In₂O₃ still has apparent defects such as low catalytic performance. Herein, porous hollow structured CuIn bimetallic catalysts were successfully synthesized by synchronous spray pyrolysis method and used for methanol formation through CO₂ hydrogenation. The impact of metal composition on the formation of CuIn bimetallic compounds, as well as the catalytic performance and other relevant characteristics were systematically studied. The results demonstrate that the bimetallic catalyst undergoes a notable physical phase change in response to alterations in the Cu:In molar ratio, resulting in the emergence of a Cu₁₁In₉ phase. Furthermore, the synergistic interaction between Cu₁₁In₉ and In₂O₃ has a considerable promotion on the catalytic activity. As the Cu: In molar ratio reaches 1:2, the obtained catalyst exhibits optimal synergistic interactions between Cu₁₁In₉ and In₂O₃, leading to the highest metal Cu dispersion, the largest active surface area, the greatest oxygen vacancy content, and the excellent CO₂ adsorption capacity. Therefore, the best catalytic activity is achieved on the Cu:In (1:2) catalyst, which owns great potential as a candidate for CO₂ hydrogenation to methanol.