Refining the band structure of BiOBr nanosheets through the synergetic effect of VO ions replacement and oxygen vacancies for promoted visible-light-driven photocatalysis

• Published in: CrystEngComm 2021-05, Vol.23 (2), p.3731-3743
• Main Authors: Wang, Lulu, Zhao, Changming, Xiang, Zhengrong, Zhang, Yi, Ma, Nan, Shen, Jie, Peng, Xiahui, Zhang, Shiying, Li, Zhongfu, Wu, Zhaohui
• Format: Article
• ISSN: 1466-8033
• DOI: 10.1039/d1ce00468a

Normally, the band structure of a photocatalyst can be tuned by surface oxygen vacancies or element doping, however, employing the synergetic effects of surface oxygen vacancies and oxyacid group replacements to regulate the band structure of the photocatalyst is challenging. Here, the band structure of BiOBr nanosheets was regulated by surface oxygen vacancies and VO 3 − ions replacement through a hydrothermal VO 3 − ions exchange route, in which the VO 3 − transform into VO 4 3− for BiVO 4 and BiV 1.025 O 4+ x . The crystal phase of the products evolved from BiOBr, BiOBr/BiVO 4 , BiOBr/BiVO 4 /BiV 1.025 O 4+ x , and BiVO 4 /BiV 1.025 O 4+ x accordingly, when gradually increasing the concentration of VO 3 − (NH 4 VO 3 ) from 0.05 to 3.0 mmol. In particular, the BiOBr nanosheets with surface oxygen vacancies and VO 4 3− ion replacement (by adding 0.05 mmol of VO 3 − ) possessing defective states and more negative conduction band potential could promote visible-light-driven photocatalytic performances of organic contaminants due to the effective separation of charge carriers. This work provides new insight into refining the band structure of photocatalysts and evidential proof of a phase transition through oxyacid exchange. The band structure of BiOBr nanosheets is regulated by the oxygen vacancies and VO 4 3− ions replacement. The BiOBr nanosheets possess defective states and a more negative conduction band potential, promoting visible-light photocatalytic activity.