Optimizing the Carbon Dioxide Reduction Pathway through Surface Modification by Halogenation
Zailun Liu, Wenjun Jiang, Zhe Liu, Yuhong Wang, Dan Wang, Derek Hao, Wei Yao, Fei Teng
Abstract
Abstract Facilitating the charge separation of semiconductor photocatalysts to increase the photocatalytic CO 2 reduction activity has become a great challenge for sustainable energy conversion. Herein, the surface halogen‐modified defect‐rich Bi 2 WO 6 nanosheets have been successfully prepared to address the aforementioned challenge. Importantly, the modification of surface with halogen atoms is beneficial for the adsorption and activation for CO 2 molecules and charge separation. These properties have been analyzed by experimental and theoretical methods. DFT calculations revealed that the modification of the Bi 2 WO 6 surface with Br atoms can decrease the formation energy of the *COOH intermediate, which accelerates CO 2 conversion. All halogen‐modified defect‐rich Bi 2 WO 6 nanosheets showed an enhanced photocatalytic CO 2 reduction activity. Specifically, Br−Bi 2 WO 6 exhibited the best CO generation rate of 13.8 μmol g −1 h −1 , which is roughly 7.3 times as high as the unmodified defect‐rich Bi 2 WO 6 (1.9 μmol g −1 h −1 ). Moreover, in the presence of a cocatalyst (cobalt phthalocyanine) and a sacrificial agent (triethanolamine), Br−Bi 2 WO 6 exhibited an even further improved CO generation rate of 187 μmol g −1 h −1 . This finding provides a new approach to optimize the CO 2 reduction pathway of semiconductor photocatalysts, which is beneficial to develop highly efficient CO 2 reduction photocatalysts.