Facile synthesis of intercalated Z-scheme Bi2O4/g-C3N4 composite photocatalysts for effective removal of 2-Mercaptobenzothiazole: Degradation pathways and mechanism

Designing and synthesizing visible-light-driven photocatalysts with superior photocatalytic performance for purifying polluted water is deemed to be a preferred tactics in settling environmental pollution. Herein, an original intercalated Z-scheme Bi2O4/g-C3N4 (BC) composite photocatalyst is successfully synthesized via calcination-hydrothermal means. The optimized 5BC composite photocatalyst (0.03567 min(-1)) shows dramatically improved photocatalytic activity compared with pure Bi2O4 (0.02204 min(-1)) and g-C3N4 (0.00623 min(-1)) in degrading 2-Mercaptobenzothiazole (MBT), which could be ascribed to the synergistic effect of the intercalation structure and the Z-scheme heterojunction, thereby realizing spatial charge separation and visible light adsorption. Additionally, the 5BC heterojunction photocatalyst exhibits good stability in terms of catalytic activity and structure after 4 cycles of experiments. From the perspective of free radical trapping experiments and ESR, the degradation of MBT is mainly controlled by O-2(-) and h(+) and follows the Z-scheme degradation mechanism. We also certificate that H2O2 produced during MBT degradation plays a momentous function through POPHA fluorescence detection method. Therefore, this work provides an alternative to building high performance and low cost photocatalysts for controlling environmental pollution. (C) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.