One-step synthesis of a novel Z-scheme m-Bi2O4/Bi2O4−x heterojunction for enhanced degradation of organic dyes and phenol under visible light

Abstract

A novel Z-scheme heterojunction photocatalyst m-Bi2O4/Bi2O4−x was fabricated through one-step hydrothermal method. It demonstrates that the load rate of Bi2O4−x in heterojunction could be easily controlled by adjusting the amount of reactant. In comparison with the pure m-Bi2O4, m-Bi2O4/Bi2O4−x heterojunction photocatalyst exhibited enhanced photocatalytic activity for rhodamine B (RhB), phenol and methyl orange degradation. Rate constants (k) for these processes catalyzed by m-Bi2O4/Bi2O4−x could reach to 0.10171, 0.26657 and 0.44218 min−1 under visible light, respectively, which were about 3.1, 1.7 and 1.3 times for the pure m-Bi2O4. This enhanced performance could be attributed to the formation of Z-scheme heterojunction between m-Bi2O4 and Bi2O4−x, which effectively promoted the charge separation and transfer efficiency. Furthermore, the charge-carrier separation mechanism of RhB degradation by m-Bi2O4/Bi2O4−x was proposed based on the Z-scheme heterojunction. This study provides a relative convenient strategy to construct Bi2O4-based heterojunctions. Considering the excellent photocatalytic activity for various organic pollutants under visible light, this work provides a possible guide to the design of Bi-based photocatalyst with enhanced activity.