Unlocking enhanced photo-Fenton, night-Fenton, and photocatalytic activities of dual Z-scheme MoS₂/WO_3–x/Ag₂S core-shell structure via defect engineering

Memory catalysis and conventional Fenton reactions are intended to counteract prevailing energy and environmental crises; however, poor performance and the need for UV irradiation question their sustainability. Herein, we demonstrate defect-engineered, dual Z-scheme MoS₂/WO_3–x/Ag₂S exhibiting enhanced photo-Fenton (PFR), night-Fenton (NFR), and photocatalytic activities (PR) against tetracycline (TC) and Rhodamine B (RhB). Defects enable the catalyst to store ample electrons just like metals, which play a vital role by exciting H₂O₂ during Fenton reactions. It removed 91.54 %, 76.43 %, and 83.39 % TC (40 mg L^–1) in 100 min and registered degradation rate constants of 0.05379, 0.02858, and 0.04133 min^–1 against RhB (20 mg L^–1) during PFR, NFR, and PR respectively. The total organic carbon (TOC) removal rates reached 58.56 % and 60.88 % during TC and RhB degradations in PFR, respectively. Solid and Liquid EPR analysis shows it can excite H₂O₂ to carry Fenton reactions with and without light. It demonstrates wide pH adaptability and tremendous potential to simultaneously counter energy and environmental crises.