Novel MIL-53(Fe)/SnS2 Z-scheme heterojunction as photoactivator of peroxymonosulfate for efficient degradation of RhB

The construction of heterojunction photocatalysts with high efficiency for activating peroxymonosulfate (PMS) to degrade organic pollutants has aroused wide concern. Herein, a novel MIL-53(Fe)/SnS 2 Z-scheme heterojunction photocatalyst was successfully prepared by solvothermal method , which was used for the degradation of rhodamine B (RhB) in the catalyst/PMS system under visible light irradiation. The results showed that the MIL-53(Fe)/SnS 2 -3 % (3 % is the mass ratio of SnS 2 to MIL-53(Fe)) displayed the highest activity reaching a RhB (10 mg/L, 100 mL) removal rate of 85.6 % within 60 min with catalyst and PMS dosage of 0.1 and 0.1 g/L, respectively. The corresponding reaction rate constant exceeded that of MIL-53(Fe) and SnS 2 by a factor of 1.39 and 6.39 times, respectively. The enhanced performance of MIL-53(Fe)/SnS 2 /PMS system can be attributed to the Z-scheme heterojunction formed between MIL-53(Fe) and SnS 2 , which inhibits the recombination of photogenerated electron-hole pairs. The PMS activation mechanism by MIL-53(Fe)/SnS 2 was proposed based on the detailed catalyst characterization, degradation efficiency tests, electron paramagnetic resonance and radical quenching experiments. Furthermore, the MIL-53(Fe)/SnS 2 exhibited good stability and suitability for different environmental conditions. This work provides a valuable guide for the development of Fe-based metal-organic frameworks (MOF) composites for photoactivation of PMS to remove organic dyes in aquatic environment. The Z-scheme heterojunction was responsible for the effective separation of photogenerated charges and the enhanced photocatalytic activity, and ·SO 4 − , ·OH and ·O 2 − are the main reactive radicals engaging in the degradation of RhB. • The MIL-53(Fe)/SnS 2 composite was successfully constructed via a solvothermal method. • The MIL-53(Fe)/SnS 2 can be used as an effective activator for PMS in RhB degradation under visible light irradiation . • The MIL-53(Fe)/SnS 2 was almost impervious to common inorganic anions and remained highly effective across a wide pH range. • The degradation pathway of RhB and photocatalytic mechanism of the MIL-53(Fe)/SnS 2 /PMS system were proposed.