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

Abstract

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 O2- 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.