Exploring the mechanism of electron transfer-mediated peroxymonosulfate activation over Cu-based catalyst for the selective decomposition of bisphenol A

Abstract

Effective degradation of aquatic contaminants highly depends on the adsorption of peroxymonosulfate (PMS) on active sites of catalysts. However, the influence of PMS adsorption state on PMS activation remains unclear. In this study, we investigated the catalytic performance of a Cu-NC catalyst, composed of dispersed Cu atoms on a nitrogen-doped carbon skeleton, for the activation of PMS in decomposing bisphenol A (BPA). The Cu-NC-4 catalyst exhibited remarkable selectivity and efficiency, achieving a kinetic rate of 0.997 min−1 with over 99.9% BPA removal in just 3 min. Through various experiments and characterizations, we determined that the degradation process was primarily facilitated by electron transfer from BPA to Cu-NC. Furthermore, the dosing sequence of PMS and pollutants was found to be crucial in the system. Density functional theory (DFT) simulation revealed that PMS with bridging adsorption on the Cu site exhibited more favorable adsorption energy, leading to enhanced electron transfer and more efficient and selective destruction of electron donors. Based on these findings, we propose a mechanism in which the electron donor plays a crucial role in PMS activation, while the nearby Cu sites optimize the adsorption configuration of PMS, thereby boosting electron transfer. These two factors synergistically contribute to the efficient removal of pollutants.