Fabrication of Black In2O3 with Dense Oxygen Vacancy through Dual Functional Carbon Doping for Enhancing Photothermal CO2 Hydrogenation

Abstract Photothermocatalytic CO 2 reduction as the channel of the energy and environmental issues resolution has captured persistent attention in recent years. In 2 O 3 has been prompted to be a potential photothermal catalyst in this sector on account of its unique physicochemical properties. However, different from the metal‐based photothermal catalyst with the nature of efficient light‐to‐thermal conversion and H 2 dissociation, the wide‐bandgap semiconductor needs to be modified to possess wide‐wavelength‐range absorption and the active surface. It remains a challenge to achieve the two aims simultaneously via a single material modulation approach. In this study, one strategy of carbon doping can empower In 2 O 3 with two advantageous modifications. Carbon doping can reduce the formation energy of oxygen vacancy, which induces the generation of oxygen‐vacancy‐riched material. The introduction of oxygen defect levels and carbon doping levels in the bandgap of In 2 O 3 significantly reduces this bandgap, which endows it full‐spectral and intensive solar light absorption. Therefore, the carbon doped In 2 O 3 achieves effective light‐to‐thermal conversion and delivers a 123.6 mmol g –1 h –1 of CO generation rate with near‐unity selectivity, as well as prominent stability in photothermocatalytic CO 2 reduction.