Synergistic mediation of dual donor levels in CNS/BOCB-OV heterojunctions for enhanced photocatalytic CO 2 reduction

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-02, Vol.12 (6), p.3398-3410
• Main Authors: Fang, Ruiming, Yang, Zhongqing, Sun, Jiajun, Zhu, Chenxuan, Chen, Yanglin, Wang, Ziqi, Xue, Can
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA07006A

We have successfully grown BiOCl x Br 1− x nanosheets with oxygen vacancies (BOCB-OV) on the surface of ultrathin g-C 3 N 4 (CNS) to form heterostructures through a solvothermal approach that creates N-vacancies on CNS. The heterojunction formation promotes CO 2 adsorption with activation and broadens light-harvesting capabilities. Moreover, the intimate contact between CNS and BOCB-OV creates an interfacial electric field directed from CNS to BOCB-OV, facilitating separation and transfer of photogenerated charge carriers. Importantly, introduction of nitrogen/oxygen vacancies in CNS/BOCB-OV leads to new donor energy levels in the bandgap, which boosts the light absorption capacity and provides a stable pathway for charge transfer across heterojunctions. Consequently, the CNS/BOCB-OV heterostructures exhibited greatly enhanced photocatalytic activities for CO 2 reduction. Further, by combining DFT calculation and in situ FTIR characterization, the photocatalytic reaction mechanism and possible CO 2 reduction pathways are elucidated. The combination of heterostructure construction and defect engineering provides a promising strategy for developing efficient two-dimensional heterostructure photocatalysts.