Engineered In2O3 nanorods with abundant O vacancies significantly boost highly efficient photothermal CO2 hydrogenation into CO

Abstract

Rising global demand for clean energy and carbon reduction challenges traditional CO₂ conversion. Photothermal catalytic CO₂ hydrogenation, powered by the combined force of light and heat, offers enhanced energy efficiency, lower reaction temperatures, and better product selectivity. Herein, a nanorod-shaped In₂O₃ catalyst rich in oxygen vacancies (Vos-In₂O₃) was synthesized. Compared to bulk In₂O₃, the rod-like structure effectively increases the catalyst's specific surface area, exposing more surface active sites. To facilitate reactant activation, oxygen defect engineering was implemented on the nanorod surface. The Vos-In₂O₃ exhibits a remarkable enhancement in the yield of photothermal CO₂ catalytic reduction to CO, CH₄, CH₃OH, and CH₃CH₂OH at lower heating temperatures and atmospheric pressure. Notably, the CO production rate at an initial C/H ratio of 3 in the filling gas mixture was close to 421.90 μmol g⁻¹ h⁻¹, which was 24.3 and 30.9 times higher than that of In₂O₃ and bulk In₂O₃, respectively. The product selectivity of CO for Vos-In₂O₃ reached an outstanding 98.96%. Introducing O vacancies accelerates reaction kinetics and thermodynamics, and strongly promotes the efficient progress of the photothermal CO₂ hydrogenation reaction.