In 2 O 3 -CNT catalysts enable >500-hour stable CO 2 -to-methanol hydrogenation via vacancy stabilization
2026-03-20
Indium oxide (In 2 O 3 ) is a promising catalyst for carbon dioxide (CO 2 ) hydrogenation to methanol but suffers from rapid deactivation due to localized over-reduction of surface In 3+ species into inactive metallic In 0 near hydrogen (H 2 ) activation sites. Here, we exploit a proton-electron dual-transfer mechanism through a physically integrated In 2 O 3 -carbon nanotube (In 2 O 3 -CNT) system, achieving simultaneous enhancement of catalytic performance and durability. The optimal In 2 O 3 -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 In 2 O 3 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 CO 2 activation while preventing localized electron accumulation and In 0 segregation. The CNT-mediated redox modulation stabilizes a dynamic InO x surface phase by balancing H 2 -induced reduction and CO 2 -driven oxidation, thereby sustaining catalytic activity over extended operation.