Effective solar light-driven isothiazolinone degradation by morphology- and oxygen vacancy-modified Gd-doped BiOCl

Antibacterial isothiazolinones are refractory organic pollutants towards biodegradation, existing in reverse osmosis concentrated water and other relevant industrial wastewater, which need to be decomposed before getting discharged into a water body. Herein, we synthesized Gd-doped flower-like hierarchical BiOCl (PGE-BiOCl) with promoted visible light response using a facile solvothermal method. The pseudo-first-order rate constant of 1,2-benzisothiazolinone-3-one (BIT) degradation was enhanced 6.49-fold by PGE-BiOCl (k = 0.610 h⁻¹) compared to BiOCl (k = 0.094 h⁻¹) under simulated visible light. It is mainly due to the synergistic effect of abundant Ovs, highly exposed (110) dominant crystal planes, and Gd doping of PGE-BiOCl. The scavenger experiments and EPR characterizations indicated that O₂˙⁻ was the dominant radical in the degradation system. The DFT calculation further confirmed the existence of O 2p orbitals near the Fermi level, which may narrow the band gap of BiOCl and improve the charge carrier separation efficiency. This work offered a promising approach for the preparation of an effective solar light-driven photocatalyst for the degradation of refractory organic pollutants in water.