In₂O₃-CNT catalysts enable >500-hour stable CO₂-to-methanol hydrogenation via vacancy stabilization

Indium oxide (In₂O₃) is a promising catalyst for carbon dioxide (CO₂) hydrogenation to methanol but suffers from rapid deactivation due to localized over-reduction of surface In³⁺ species into inactive metallic In⁰ near hydrogen (H₂) activation sites. Here, we exploit a proton-electron dual-transfer mechanism through a physically integrated In₂O₃-carbon nanotube (In₂O₃-CNT) system, achieving simultaneous enhancement of catalytic performance and durability. The optimal In₂O₃-CNT system gives the highest methanol production rate of 1250.6 grams kilograms_In2O3^-1 hour^-1 at 320°C. Particularly, the hybrid system maintains catalytic stability for >500 hours, representing the highest durability among reported In₂O₃ catalysts. Mechanistic studies and multiple characterization techniques reveal that the conductive CNT network regulates surface redox dynamics by facilitating electron transfer and redistribution. This process promotes the formation of oxygen vacancies for CO₂ activation while preventing localized electron accumulation and In⁰ segregation. The CNT-mediated redox modulation stabilizes a dynamic InO_x surface phase by balancing H₂-induced reduction and CO₂-driven oxidation, thereby sustaining catalytic activity over extended operation.