Bi2O4 decorated with SnO2 nanoparticles as direct Z‐scheme heterojunction for enhanced degradation of tetracycline under visible light irradiation

Abstract BACKGROUND Bismuth tetraoxide (Bi 2 O 4 ) has attracted increasing interest as a novel visible‐light‐driven photocatalyst. It suffers from some drawbacks, such as quick recombination of photogenerated electrons and holes, small specific surface area and few active sites due to submicron rod structure. RESULTS A novel and efficient binary heterojunction photocatalyst, in which zero‐dimensional (0D) SnO 2 nanoparticles was anchored on the surface of one‐dimensional (1D) Bi 2 O 4 micrometer rods, was successfully synthesized. The as‐prepared samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The photocatalytic activity of the synthesized photocatalysts was evaluated by photodegradation of tetracycline (TC) under visible‐light irradiation. The prepared 30‐SB composite (30 wt% SnO 2 /Bi 2 O 4 ) exhibits the highest photocatalytic activity toward TC degradation. The removal efficiency of TC was up to 84.3% within 120 min. The rate constant k for the reaction of 30‐SB composite is 0.029017 min −1 , which is 13.4 and 1.8 times as high as that of SnO 2 and Bi 2 O 4 , respectively. CONCLUSION The significantly boosted photocatalytic activity is attributed to the formation of Z‐scheme heterojunctions between SnO 2 and Bi 2 O 4 . Z‐scheme charge transfer promoted the effective separation of photogenerated carriers and ensured that the holes with higher oxidative activity and electrons with stronger reducibility participate in the production of • OH and • O 2 − as well as direct degradation of TC. This work will provide a new modification strategy for the potentially excellent photocatalyst Bi 2 O 4 . © 2022 Society of Chemical Industry (SCI).