Construction of a novel ZnWO4/MIL-53(Fe) heterojunction photocatalyst for the boosted tetracycline degradation under visible-light irradiation

Advanced photocatalytic technology plays a vital role in addressing organic pollutant degradation, and developing highly efficient heterojunction photocatalysts is one of the research hotspots in the field of photocatalysis. Herein, we integrated the merits of ZnWO 4 nanoparticles and spindle-shaped MIL-53(Fe) to construct a novel ZnWO 4 /MIL-53(Fe) heterojunction. The fabricated ZnWO 4 /MIL-53(Fe) underwent a variety of characterization. An evaluation was conducted on the photocatalytic activity and stability of ZnWO 4 /MIL-53(Fe) toward tetracycline (TC) degradation. Based on the band alignment and the production of active species, the photocatalytic mechanism and interfacial charge transfer mode were proposed. The prepared ZnWO 4 /MIL-53(Fe) composites exhibit high photocatalytic activity under visible light. The optimum composites ZnM-20 achieves the highest degradation efficiency of TC, significantly outperforming the individual components ZnWO 4 and MIL-53(Fe). The photocatalytic degradation rate constant for TC was determined as 0.01221 min −1 , which is 28.5 and 58.8 times that of MIL-53(Fe) and ZnWO 4 , respectively. The improvement in the catalytic activity of ZnM-20 is attributed to the high visible-light absorption ability, significantly enlarged specific surface area, and the greatly accelerated charge separation and migration due to the formation of the heterostructure between ZnWO 4 and MIL-53(Fe) and the cyclic redox reactions of Fe(III)/Fe(II) in MIL-53(Fe). ZnWO 4 /MIL-53(Fe) presents good stability and reusability. The light-excited charge carriers migrate in the heterojunction interface complies with Type-II transfer mechanism. This work provides a meaningful strategy for developing efficient photocatalysts for environmental remediation. • A novel heterojunction composite photocatalyst ZnWO 4 /MIL-53(Fe) is first reported. • ZnWO 4 /MIL-53(Fe) presents exceptional optical absorption in the visible region. • Heterostructure interface and cyclic redox of Fe(III)/Fe(II) improve the charge separation. • ZnWO 4 /MIL-53(Fe) exhibits excellent stability and activity with a TC removal rate of 84.4 %. • The photocatalytic mechanism and interfacial charge transfer mode were discussed.