Steering charge transfer in CuInS2/BiOCl composites to enable sunlight-driven C–F bond cleavage of PFAS in water
Fuyu Liu, Honglei Li, Zixiang Gao, Qiang Song, Patrick J. Cullen, Ziying Nie, Ye Hong, Yuxuan Zhang, Shilin Yao, Cheng Gu, Fanran Meng, Zhihong Zuo, R Q Liu, Z. N. Chen, Dongling Ma, Yongguang Yin, Yong Cai, Xiaoguang Duan, Qingzhe Zhang
Abstract
Abstract Per- and polyfluoroalkyl substances (PFAS) resist most remediation technologies because of their exceptionally inert carbon–fluorine bonds. Here we report a visible-light Z-scheme photocatalyst composed of CuInS 2 quantum dots anchored on BiOCl nanoplates (CuInS 2 /BiOCl) that overcomes this barrier. Femtosecond transient absorption, steady-state spectroscopy and theoretical calculations show that an internal electric field steers photo-generated electrons (e − ) migrating to CuInS 2 and holes (h + ) to BiOCl, maximizing their redox potentials for simultaneous carbon–fluorine scission and carbon chain breakage, respectively. Computations revealed that benzene sulfonic acid and carbon fluoride groups on sodium p -perfluorous nonenoxybenzenesulfonate (OBS) are susceptible to electrophilic attack by h + and nucleophilic attack by e − , respectively. Under ultraviolet irradiation, the heterojunction achieves 75.8% defluorination and 76.8% total organic carbon removal of OBS within 8 h, with universal applicability for efficient degradation of 17 representative PFAS mixtures. Continuous-flow tests driven by natural sunlight achieve >96% OBS removal in 10 h, confirming system scalability. Toxicity assays indicate negligible hazardous effects of the residual. The work reports a sunlight-powered and flow-compatible photocatalytic platform for sustained PFAS decontamination, opening a sustainable route for ‘forever chemical’ abatement in water.