Atomically Thin Bi/Bi4Ti3O12 Heterojunction Mediated Increasing Active Photogenerated Carriers for Boosting Photocatalytic Activity.

Two-dimensional (2D) semiconductors play an essential role in the field of photocatalytic repairing environment on account of their unique electronic structure and ultra-high specific surface area. Here, a 1-2-layer 2D ultrathin Bi/Bi4Ti3O12 (BTO-U-B2) heterojunction photocatalyst is constructed, and the delivery mechanism of electronic is proposed based on photoelectric performance and theoretical calculation results. The efficiency of separation, transfer and recombination of photogenerated carriers is considerably improved due to the enhanced internal electric field, shorter transfer distance and the introduction of electron traps, respectively. Moreover, bisphenol A (BPA) degradation rate of BTO-U-B2 heterojunction under xenon lamp is 9.06 and 2.57 times higher than that of Bi4Ti3O12 microplates and nanosheets, respectively. The enhanced photocatalytic activity benefits from the synergistic effect of 2D ultrathin structure and surface heterojunction. Additionally, the photocatalysis test are performed by replacing different environmental solutions and various organic pollutants, and results reveal that this heterojunction has a certain applicability. This work provides a deep insight into designing efficient 2D heterojunction photocatalysis.