Construction of charge transfer chain in Bi12TiO20-Bi4Ti3O12/α-Bi2O3 composites to accelerate photogenerated charge separation
Jincheng Yin, Xuebing Chen, Guanna Li, Dongxu Liu, Chun Li, Rengui Li, Bingxing Xie, Johannes H. Bitter, Jing Zhang
Abstract
Photogenerated charge separation and transfer is one of the bottleneck steps in photocatalysis, and efficient charge separation strategies are strongly desired. Here, mimicking the electron transport chain in natural photosynthesis, we report the design and fabrication of a charge transfer chain using bismuth-based semiconductor as a proof-of-concept. In view of the thermodynamic energy band positions and structural similarity based on the density functional theory (DFT) analysis, heterostructured combination of α-Bi 2 O 3 , perovskite-like Bi 4 Ti 3 O 12 , and sillenite Bi 12 TiO 20 was designed for fabrication of charge transfer chain. By tuning the molar ratio of Bi and Ti precursors, the Bi 4 Ti 3 O 12 and Bi 12 TiO 20 particles were formed on the surface of α-Bi 2 O 3 by an in-situ transformation process, giving rise to Bi 12 TiO 20 -Bi 4 Ti 3 O 12 /α-Bi 2 O 3 composites with charge transfer chain. We propose that the effective charge transfer is accomplished among α-Bi 2 O 3 , Bi 12 TiO 20 , and Bi 4 Ti 3 O 12 , which significantly improves the photogenerated charge separation and transfer, as indicated by photoluminescene, time-resolved photoluminescene, and electrochemical impedance spectra results. As expected, the Bi 12 TiO 20 -Bi 4 Ti 3 O 12 /α-Bi 2 O 3 shows the superior photocatalytic activity for the degradation of environmental pollutants with high concentration. Even for the refractory pollutants like 4-chlorophenol, the optimal Bi 12 TiO 20 -Bi 4 Ti 3 O 12 /α-Bi 2 O 3 composite shows 28 times higher than that of α-Bi 2 O 3 for photocatalytic degradation, verifying the superiority of photogenerated charge transfer chain in photocatalysis. This work demonstrates the feasibility of the charge transfer chain strategy to boost the photogenerated charge separation, which is of great significance for designing energy and environmental-related materials in heterogonous photocatalysis.