Sunlight induced photo-thermal synergistic catalytic CO2 conversion via localized surface plasmon resonance of MoO3−xElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ta10922b

Photocatalytic conversion of CO 2 to solar fuels is considered an alternative approach for simultaneously mitigating the greenhouse effect and solving energy shortage. The efficient light harvesting and the thermochemical conversion have been demanding quests in photocatalysis due to the relatively low solar energy utilization efficiency. In this work, oxygen vacancies are induced in MoO 3 for improving photo-thermal CO 2 reduction efficiency by capturing near-infrared (NIR) photons. The localized surface plasmon resonance (LSPR) of MoO 3− x triggered by oxygen vacancies enables the efficient capture of NIR photons. Additionally, oxygen vacancies can promote the carrier separation, improve CO 2 adsorption on the defective surface and lower the barrier of CO 2 hydrogenation during the conversion process. As a result, MoO 3− x displayed dramatically enhanced photo-thermal synergistic CO 2 reduction under simulated sunlight (UV-Vis-IR) irradiation than MoO 3 . The amount of CO produced by MoO 3− x can reach 10.3 μmol g −1 h −1 , which is 20 times higher than that of MoO 3 (0.52 μmol g −1 h −1 ). And the CH 4 production of MoO 3− x can reach 2.08 μmol g −1 h −1 , which is 52 times higher than that of MoO 3 (0.04 μmol g −1 h −1 ). In situ FT-IR and theoretical calculations also proved the enhanced activity of MoO 3− x . This work highlights the significance of defect engineering for improving the photo-thermal catalytic conversion of CO 2 . MoO 3− x displayed dramatically enhanced photo-thermal synergistic CO 2 reduction under simulate sunlight irradiation compared to MoO 3 due to the LSPR of MoO 3− x triggered by oxygen vacancies.