In situ construction of MoS2@CoS2 spherical hydrangea-shaped clusters for enhanced visible-light photocatalytic degradation of sulfamethoxazole

Abstract

This article explores the rich element cobalt, found in the earth's crust, to replace noble metals as co-catalysts that serve as electron traps to enhance the efficiency of electron transfer from molybdenum disulfide (MoS₂) to cobalt sulfide (CoS₂). The MoS₂@CoS₂ composite photocatalyst successfully loaded nano-CoS₂ onto the spherical hydrangea-shaped MoS₂ through a simple hydrothermal synthesis. The MoS₂@CoS₂ composite can facilitate efficient electron–hole separation and active center exposure rate. MoS₂@CoS₂ exhibits an outstanding photodegradation (>95% in 180 min) of sulfamethoxazole (SMX) under visible light. Moreover, the composite can prolong the lifetime decay and improve the interfacial charge transfer between MoS₂ and CoS₂. An in-depth investigation of the charge carrier separation mechanism toward MoS₂@CoS₂ composites under visible light was proposed, which was further confirmed by capture experiments, electron spin resonance (ESR) technology, and density functional theory (DFT) calculations. Furthermore, the corresponding intermediates of the MoS₂@CoS₂ composite for the degradation of SMX were analyzed by liquid chromatography-mass spectrometry (LC-MS), and the possible degradation pathways were proposed.