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• BiOI is an excellent connector between ZnFe 2 O 4 and AgI to form a double Z-type heterojunction structure ZnFe 2 O 4 /BiOI/AgI composite through precise electronic regulation. • The existence of a double Z-heterojunction structure and Ag0 makes the electrons on the interface transfer and separate effectively. • Rich oxygen vacancies also provide more active sites for photocatalysis and photo-Fenton process. As a bridge, BiOI nanosheets connect ZnFe 2 O 4 nanoparticles and AgI clusters (∼300 nm) via hydrothermal-coprecipitation. A ternary composite with a double Z-type heterojunction structure is obtained through precise electronic regulation. Compared with ZnFe 2 O 4 and ZnFe 2 O 4 /BiOI, the photo-Fenton degradation RhB of ZnFe 2 O 4 /BiOI-AgI-3 samples is obviously improved under simulated sunlight. Rich oxygen vacancies also provide more active sites for photocatalysis and photo-Fenton process. The main active specie in photo-Fenton degradation is ·OH. The existence of a double Z-heterojunction structure and Ag0 makes the electrons on the interface transfer and separate effectively. Notably, the intensity of PL luminescence ZnFe 2 O 4 /BiOI/AgI is lower than that of ZnFe 2 O 4 and ZnFe 2 O 4 /BiOI because of reducing the recombination rate of photogenerated carriers. ZnFe 2 O 4 /BiOI/AgI composites have excellent stability of photo-Fenton degradation. Furthermore, the formation of a built-in electric field inhibits the recombination of electron-hole pairs, enhances visible light absorption, results in improving the efficiency of ternary composite materials to degrade pollutants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Magnetically separable MnFe 2 O 4 nanoparticles are synthesized onto SnS 2 microflowers to fabricate a Z-scheme MnFe 2 O 4 @SnS 2 heterojunction. • The MnFe 2 O 4 @SnS 2 -2 composite photocatalyzes 92.08 % degradation of MB at 120 min under pH = 9 and 1.5 mL H 2 O 2. • MnFe 2 O 4 @SnS 2 heterojunction possesses the widened band gap and weakened luminescence. • OH is the main active specie in photo-Fenton degradation. The magnetically separable MnFe 2 O 4 nanoparticles (15–50 nm) are synthesized onto SnS 2 microflowers (diameter 1–1.5 μm, thickness 50 nm), fabricating a direct Z-scheme MnFe 2 O 4 @SnS 2 heterojunction nanocomposite via two-step hydrothermal. The MnFe 2 O 4 @SnS 2 composites with an appropriate SnS 2 content exhibit enhanced photo-Fenton degradation performances to make efficient separation of photoexcited electron/hole pairs. In the photo-Fenton degradation tests, MnFe 2 O 4 @SnS 2 -2 shows excellent performance that 92.08 % of methylene blue (MB) could be photocatalyzed within120 min with pH = 9 and 1.5 mL H 2 O 2 , which is about 2.43 times than that of bare MnFe 2 O 4 nanoparticles. In general, the Mn2+ and Fe2+ in-situ regenerated through accepting electrons from the cathode as the result of the Z-scheme electron transfer. Moreover, over 88 % of MB is still removed in the 5th run is attributed that SnS 2 driven also extend the longevity of the MnFe 2 O 4 catalyst. Different capture agents IPA, BQ and TEOA investigation displays that ·OH is the main active specie. [ABSTRACT FROM AUTHOR]