Abstract: Metal-based catalysts are prevalent in the CO₂ hydrogenation to methanol owing to their remarkable catalytic activity. Herein, Ru/In₂O₃ catalysts with different morphologies obtained by doping Ru into In₂O₃ with irregular, rod-like, and flower-like morphologies are used for catalytic CO₂ hydrogenation to methanol. Results indicate that the flower-like Ru/In₂O₃ (Ru/In₂O₃-F) exhibits higher catalytic performance than Ru/In₂O₃ with other morphologies, achieving a 12.9 % CO₂ conversion, 74.02 % methanol selectivity, and 671.36 mg_MeOH h^-1 g_cat^-1 methanol spatiotemporal yield. Furthermore, Ru/In₂O₃-F maintains its catalytic stability over 200 h at 5 MPa and 290 °C. The promotional effect mainly stems from the fact that electronic structure of Ru can be effectively adjusted by modulating the morphology of In₂O₃. The strong interaction between atomically dispersed Ru and In₂O₃-F enhances the structural stability of Ru, inhibiting the agglomeration of the catalyst during the reaction process. Furthermore, density-functional theory calculations reveal that highly dispersed Ru atoms not only perform efficient and rapid electronic gain and loss processes, facilitating the catalytic activation of H₂ into H intermediates. It also enables the generated reactive H to rapidly overflow to the surrounding In sites to participate in CO₂ reduction. These findings provide a theoretical basis for the development of high-performance catalysts for CO₂ hydrogenation.

Key words: CO2 hydrogenation, Methanol, Morphology, Atomic dispersion, Ruthenium