Bubble induced piezoelectric activation of peroxymonosulfate on BiOCl for formaldehyde degradation during the absorption process: a density functional theory study

Abstract

Gas bubbling during solution absorption can induce strain on piezoelectric materials, which can be used to activate peroxymonosulfate (PMS). Persulfate-based advanced oxidation methods can improve the absorption efficiency of volatile organic compounds (VOCs) and achieve the continuous removal of VOCs. However, the coupling of piezoelectric catalytic and persulfate activation for VOC degradation has never been reported. In this study, density functional theory (DFT) was used to investigate PMS activation by BiOCl (001) with strains and the microscopic mechanism of typical VOC degradation. The results demonstrate that BiOCl (001) with −4% strain has the best performance on PMS activation. Formaldehyde (HCHO) was chosen as the model pollutant owing to its simple molecular structure among the various common pollutants (C₆H₆, CH₂Cl₂, and HCHO) considered. The barrier-free reaction pathway for HCHO degradation in the BiOCl/PMS system is determined without the formation of the harmful by-product CO. Therefore, the coupling of piezoelectric catalysis and PMS activation for HCHO degradation was realized on BiOCl (001). The piezoelectric effect can greatly improve the activation efficiency of PMS, thus greatly improving the degradation performance of HCHO. Furthermore, this work systematically studied the relationship among the electronic structure of BiOCl, the activation of PMS, and the degradation of HCHO, which provides a valuable idea for the further exploration of the novel VOC treatment system.