Oxygen vacancy triggering the broad-spectrum photocatalysis of bismuth oxyhalide solid solution for ciprofloxacin removal Mengxia Ji a , Yifan Shao b , Emmanuel Nkudede a , Zihan Liu a , Xing Sun a , Junze Zhao a , Ziran Chen c , Sheng Yin a,⇑ , Huaming Li a,⇑ , Jiexiang Xia a,⇑ a Institute for Energy Research, School of Chemistry and Chemical Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, PR China b Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Provincial Key Laboratory of Resources Chemistry of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 81008, PR China c Department of Architecture and Environment Engineering, Sichuan Vocational and Technical College, Suining 629000, PR China graphical abstract The oxygen vacancy-rich mediated BiOCl 0.5 I 0.5 solid solution was synthesized via ionic liquid assisted solvothermal method. The realized broad-spectrum photocatalytic activity towards antibiotic ciprofloxacin (k > 580 nm) of BiOCl 0.5 I 0.5 materials mainly attributed to the modulated the electronic state and energy band position by tailoring the surface oxygen vacancy concentration. article info Article history: Received 1 April 2022 Revised 9 June 2022 Accepted 18 June 2022 Available online 20 June 2022 Keywords: Oxygen vacancy Broad-spectrum Solid solution abstract The construction of a broad-spectrum photocatalytic system is of great significance for maximizing the utilization of solar energy. Herein, a surface oxygen vacancy triggering high-efficient broad-spectrum BiOCl 0.5 I 0.5 solid solution photocatalyst was successfully fabricated via a one-pot solvothermal process. The UV–vis diffuse reflectance spectra revealed that the introduced oxygen vacancy appears to extend the absorption region of BiOCl 0.5 I 0.5 to a wider wavelength range. Under k > 580 nm light irradiation for 5 h, nearly 85.6% ciprofloxacin was degraded by BiOCl 0.5 I 0.5 with rich oxygen vacancy, the ciproflox- acin removal efficiency was 3.4 times higher than that with less oxygen vacancy. Moreover, the density functional theory calculations and photoelectrochemical characterizations indicated the excited elec- trons would preferentially transfer to the new defect level induced by oxygen vacancy, thus greatly https://doi.org/10.1016/j.jcis.2022.06.076 0021-9797/Ó 2022 Elsevier Inc. All rights reserved. ⇑ Corresponding authors. E-mail addresses: yinsheng@ujs.edu.cn (S. Yin), lhm@ujs.edu.cn (H. Li), xjx@ujs.edu.cn (J. Xia). Journal of Colloid and Interface Science 626 (2022) 221–230 Contents lists available at ScienceDirect Journal of Colloid and Interface Science journal homepage: www.elsevier.com/locate/jcis