Engineering Dual‐Defective 0D/2D V<sub>N</sub>‐CNQDs/V<sub>Bi</sub>‐Bi<sub>4</sub>O<sub>5</sub>Br<sub>2</sub> S‐Scheme Heterostructure for Boosting CO<sub>2</sub> Photoreduction in Air
Manning Zha, Lili Ai, Rui Sheng, Chuan Seng Tan, Yuchun Li, Nannan Guo, Mengjiao Xu, Dianzeng Jia, Luxiang Wang
Abstract
Abstract The direct photocatalytic reduction of CO 2 in air is the future trend of photocatalyst application. Herein, the 0D carbon nitride quantum dots with nitrogen vacancies (V N ‐CNQDs) and 2D bismuth‐deficient Bi 4 O 5 Br 2 (V Bi ‐Bi 4 O 5 Br 2 ) are integrated by hydrothermal method. The S‐scheme heterostructure of V N ‐CNQDs/V Bi ‐Bi 4 O 5 Br 2 composite promotes the separation rate of photogenerated carriers and enhances the redox capacity. The dual defects provide a large number of adsorption and catalytic sites that enhance the ability to capture and reduce CO 2 . The synergistic effect of S‐scheme heterostructure and defect engineering enables the efficiency of CO 2 photoreduction to CO with V N ‐CNQDs/V Bi ‐Bi 4 O 5 Br 2 to reach 16.89 µmol g −1 h −1 in air and 55.69 µmol g −1 h −1 in V CO2 : V Air = 3:1 condition, which is 17 and 21 times higher than that of Bi 4 O 5 Br 2 , respectively. The dual‐defective V N ‐CNQDs/V Bi ‐Bi 4 O 5 Br 2 exhibits more lower energy barrier for forming * CO 2 , * COOH, and * CO and is easier to release CO gas. And it exhibits excellent cycling stability for photocatalytic CO 2 reduction to CO. The photocatalytic reduction mechanism of CO 2 to CO in the V N ‐CNQDs/V Bi ‐Bi 4 O 5 Br 2 S‐scheme heterostructure is further analyzed. This work provides new perspectives for the design of the photocatalysts with defect engineering for efficient photoconversion at low CO 2 concentrations.