The Mars–van Krevelen cycle and fine-customized d-band centers promoting S-scheme heterojunction charge transfer on wide solar-spectrum photocatalytic water purification

This study constructed an S-scheme MIL( Fe )DCA (et al., 2023b (6)) /MoS 2 heterojunction for enhanced performance in degrading pollutants under a wide spectrum, benefiting from the customized d-band centers (by the built-in electric field) and the Mars–Van Krevelen cycle. Results reveal the tetracycline degradation rate of MIL( Fe )DCA (et al., 2023b (6)) /MoS₂ (~95 %) increases 1.38-fold and 11.8-fold compared to pristine MIL-Fe-DCA and MoS 2 , respectively, with better repeatability.Also, satisfactory reduction of Cr(VI) ions (75 %) and removal of coumarin (81.3 %) and ciprofloxacin hydrochloride (83 %) are observed. The catalyst exhibits rich defects, wide-spectrum solar light harvesting, efficient separation of h +  ~ e − pairs and a robust redox process. It is found that the charge transfer in the S-scheme interfacial electric field elevates the d-band center towards the Fermi level, which can effectively lower water activation energy to more easily produce •OH, enhancing intermediate adsorption on the catalyst's surface, thus facilitating charge transfer and accelerating reaction kinetics. Another major emphasis is the oxygen defects induced Mars–Van Krevelen cycle, wherein adsorbed reactants, lattice oxygen, h + , •O 2 − , Fe 2+ and Fe 3+ participate in the reaction processes, which contributes to the photo-thermal conversion, achieving the synergy between photocatalysis and photothermal catalysis. This work offers a synergetic strategy involving the interfacial electric field, d-band center, and photo-thermal effect for photocatalytic water purification.