Modulation of reactive species in peroxymonosulfate activation by photothermal effect: A case of MOF-derived ZnFe2O4/C

Abstract

Tuning reactive oxygen species in peroxymonosulfate (PMS) activation by the structure of catalysts has been extensively studied. But in photocatalysis, the photothermal effect is lack of attention on the alteration of reactive species produced by PMS activation. In this work, ZnFe2O4/C photocatalyst with oxygen vacancy (ZFOv/C) was synthesized via the calcination of bimetallic Zn/Fe-metal–organic framework. The photocatalytic performance of the catalyst had been studied under several conditions, and the experimental results demonstrated that the photocatalytic reaction rate constant of ZFOv/C photocatalyst without temperature control was 21.3 % higher than that under temperature control. Reactive species quenching experiments and electron paramagnetic resonance indicated that 1O2 and h+ are the primary reactive species without temperature control, while only 1O2 are the dominant reactive species under temperature control conditions. The possible activation site was speculated by in-situ Raman spectroscopy, XPS spectra and cycling experiment. This paper analyzes the reasons for photocatalysis to improve the degradation rate of pollutant from the perspective of the change of reactive species generated by photothermal effect on PMS activation, which may open up opportunities to explore the maximum utilization of sunlight in PMS activation.