Chinese Journal of Catalysis ›› 2025, Vol. 75: 164-179.DOI: 10.1016/S1872-2067(25)64756-5

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Facet-induced reduction directed AgBr/Ag0/TiO2{100} Z-scheme heterojunction for tetracycline removal

Xiong Qia,1, Shi Quanquana,*,1(), Wang Binlic, Baiker Alfonsd, Li Gaob,*()   

  1. aCollege of Science, Inner Mongolia Agricultural University, Hohhot 010018, Inner Mongolia, China
    bDalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
    cShenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
    dInstitute for Chemical and Bioengineering, ETH Zurich, Hönggerberg, HCI, CH-8093 Zurich, Switzerland
  • Received:2025-03-14 Accepted:2025-05-26 Online:2025-08-18 Published:2025-07-22
  • Contact: *E-mail: qqshi@imau.edu.cn (Q. Shi), gaoli@dicp.ac.cn (G. Li).
  • About author:1Contributed equally to this work.
  • Supported by:
    central guidance for local scientific and technological development funds(2022ZY0081);Natural Science Foundation of China(22065029)

Abstract:

Given their unique structure-dependent properties, strategically designing semiconductor-based photocatalysts, which expose highly reactive crystalline facets, is widely used to tune their performance. Herein, AgBr/Ag/TiO2{100} nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction. Transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations reveal that the selective exposure of TiO2{100} facets with abundant oxygen vacancies (OV) promotes the formation of metallic silver on the interfaces between AgBr and TiO2{100}. Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO2{100} and the valence band of AgBr. As a result, a Z-scheme heterojunction is formed in AgBr/Ag/TiO2{100}. The AgBr/Ag/TiO2{100} exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr, TiO2{101}, TiO2{100} and AgBr/TiO2{101} p-n heterojunctions. This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers, which is confirmed by femtosecond transient absorption spectroscopy. The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates. Overall, this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO2.

Key words: Facet-induced reduction, AgBr/Ag0/TiO2{100}, Z-scheme heterostructure, Oxygen vacancy, Photocatalysis, Tetracycline degradation