Microenvironment modulation of MoS2-based single-atom catalyst for accelerating electron-transfer process to activate PMS and degrade pollutant

Abstract

The application of peroxymonosulfate (PMS)-based advanced oxidation processes, facilitated by the incorporation of metal-deposited MoS2 catalyst, has attracted considerable interest in recent years within the scientific community. Nevertheless, investigating the structure-performance relationship between MoS2 and deposited metal still presents a formidable challenge, yet a highly desirable pursuit. In this study, a Cu-MoS2 single-atom catalyst (SAC) was successfully synthesized by a photo-deposition method, wherein Cu ions were deposited on the MoS2 surface. The Cu-MoS2/PMS system exhibits exceptional degradation performance for tetracycline (TC), with a removal efficiency reaching 96% at 60 min. Furthermore, the density functional theory (DFT) is applied to investigate the coordination microenvironment of the catalyst by depositing of Cu. Experimental and theoretical calculations results exhibit that, on one hand, the introduction of Cu decreases the adsorption energy barrier and enhances the adsorption capacity of the catalyst for PMS. On the other hand, the abundant presence of Cu on the surface of the MoS2 facilitates an accelerated transfer of electron, availing the formation of reactive oxygen species (ROS) via the distinct pathway: MoS2 → transition metal → PMS. Concurrently, the synergistic interaction between Mo and Cu expedites rapid valence evolution of Mo4+/Mo5+/Mo6+ and Cu+/Cu2+, thereby further enhancing the PMS activation. Hence, adjusting the coordination microenvironment of the catalyst represents a promising strategy for enhancing the catalytic activity.