Facile in situ fabrication of a direct Z-scheme BiOCl/bismuth niobate heterojunction and its effective photodegradation of RhB

Abstract

Bismuth-based photocatalytic technology has been a promising way to degrade contaminants in the aqueous system. In this work, a direct Z-scheme BiOCl/Bi₃NbO₇ heterojunction with a different molar ratio of Bi and Nb elements was fabricated through a facile in situ growth method. The structural and photoelectric characteristics of these as-prepared samples were investigated by SEM, XPS, TEM, XRD, BET, UV-vis DRS, PL, EIS and TPC. The photocatalytic activity was evaluated by the degradation of RhB, and its mechanism was analyzed by the active species trapping experiments and DFT calculation. The results showed that compared with other as-prepared samples, BN-4 had the highest activity for RhB degradation with the value of the rate constant (k) being 0.01664 min⁻¹. The reason that might be those different molar ratios of Bi and Nb elements in BiOCl/Bi₃NbO₇ heterojunction would impact the interface structure. And an appropriate molar ratio of that could bring a lower interface resistance that enhances the photocatalytic activity. The •OH and •O²⁻ were the main active substances during the RhB photocatalytic process, and a reasonable degradation pathway was proposed.

Graphical Abstract

Keywords:

• Bismuth oxychloride
• bismuth niobate
• heterojunction
• RhB
• photocatalysis

Acknowledgments

We thank the “Hongliu Excellent Young” talents support program of Lanzhou University of Technology

Additional information

Funding

This work was financially supported by China Postdoctoral Science Foundation (2019M653796), Natural Science Foundation of Gansu Province (20JR10RA197, 20JR5RA476) and Science and Technology Innovation Fund of Gansu Academy of Sciences (2019QN-08).