Enhanced CO2 Photoreduction Performance of WO3−x

Converting CO2 greenhouse gases into high-value-added fuels via semiconductor photocatalysts is an ideal solution to address current environmental and energy issues. Due to its unique physicochemical traits and flexible structure, WO3 is widely employed in photocatalysis. Nevertheless, it commonly faces problems such as limited light absorption and low reaction selectivity. Here, we effectively tackle the existing issue by introducing an oxygen defect strategy to synthesize two-dimensional WO3−x nanosheets with rich oxygen vacancies. Due to localized surface plasmon resonance (LSPR), these nanosheets may exhibit broad light absorption and efficient CO2 adsorption and activation. In the photocatalytic reduction of carbon dioxide (CO2) to carbon monoxide (CO), WO3−x nanosheets exhibited 100% selectivity and 16.1 μmol g−1 h−1 yield, 6.2 times higher than WO3. Oxygen vacancies improve WO3’s band structure and increase its capacity to absorb visible light. Based on electrochemical tests and fluorescence spectroscopy analysis, the outstanding functionality of WO3−x nanosheets is related to the improved separation and transport of photocurrents and the restricted radiative recombination of the resulting electron pairs and holes.