Efficient molecular oxygen utilization of micelle-based BiOCl for enhanced in situ H2O2 production induced photocatalytic removal of antibiotics

Abstract

Photocatalytic self-Fenton technology is regarded as a promising strategy for the removal of pollutants in wastewater, and the in situ H₂O₂ production rate is one of the main factors affecting contaminant degradation performance. However, insufficient utilization of molecular oxygen results in poor activity in photocatalytic H₂O₂ production. Herein, we propose a single-layer BiOCl nanoflower induced by biosurfactant with surface micelles to increase the oxygen adsorption and reduction rate. The DFT results demonstrated that hydrophobic groups (–CH₂–) on the surface of micelles increased the O₂ adsorption sites and then expanded the O₂ adsorption capacity of BiOCl samples, which was also confirmed by the enhancement of the O 1s peak intensity in the XPS spectra. The charge concentrated on the micelle surface can accelerate the reduction of molecular oxygen to reactive oxygen species, thus enhancing H₂O₂ production to reach 108.6 μM within 60 min in pure water. Simultaneously, single-layer BiOCl increased the utilization rate of H₂O₂ by decreasing the decomposition of H₂O₂ itself, resulting in a 16.8-fold increase in sulfamethoxazole degradation efficiency. These results can inspire further developments in the photocatalytic degradation of antibiotics based on in situ H₂O₂ production.