The synergy of sulfur vacancies and heterostructure on CoS@FeS nanosheets for boosting the peroxymonosulfate activation

The incorporation of heterostructure and vacancies will bring new strategies to improve the intrinsic activity of catalysts. Herein, the CoS@FeS heterostructure catalyst with sulfur vacancies (SVs) was fabricated by a simple hydrothermal strategy, which can synergistically trigger peroxymonosulfate (PMS) activation toward the efficient degradation of sulfamethoxazole (SMX) ( k obs , 0.3334 min −1 ) through a non-radical/radical oxidized pathway. SO 4 • – , •OH and 1 O 2 were regarded as the main reactive oxygen species (ROSs). Mechanism studies revealed that the synergy of SVs and heterostructure played an electron density adjusting role for the PMS activation into SO 4 • – and •OH, as well as the continuous generation of •O 2 − from O 2 , thereby in favor of 1 O 2 . The SVs availed the adsorption of PMS and dissolved oxygen (DO) on the surface, the continuous electron transmission would be consolidated through the charge transfer efficiency (CTE) of heterostructure. Meanwhile, the integration of SVs with heterostructure reduced the adsorption energy of PMS (-3.82 eV) on the interface of the catalyst according to the density functional theory (DFT) calculations, which overcame the repulsion effect between negatively charged HSO 5 – and CoS@FeS, and enhanced the charge transfer efficiency to accelerate the PMS activation for generating SO 4 • – and •OH. This work will propose a new approach for synergistically stimulating the intrinsic activity of catalysts to improve environmental remediation.