Facile in-situ construction of highly dispersed nano zero-valent iron modified black TiO2 Z-scheme recyclable heterojunction with highly efficient visible-light-driven photocatalytic activity

This research provides a innovatively designed mechanism of activating the passivation layer on Fe-0 surface as semiconductor to construct a Z-scheme heterojunction in-situ for high-efficiency environmental remediation. Aggregation and passivation of Fe-0 and poor visible-light absorption of TiO2 were simultaneously improved by the facile synthesis of a recyclable Fe0@black-TiO2 Z-scheme heterojunction without high-temperature hydrogen atmosphere. The results showed that tetracycline (TC) degradation efficiency with Fe0@black-TiO2 was 1.23 and 2.63 times higher than that of pristine Fe-0 and black-TiO2, respectively. The superior degradation arose from strong reduction ability of highly dispersed Fe-0 and in-situ constructed Z-scheme heterojunctions. High dispersion of Fe-0, construction of the heterojunction, enhanced photodegradability of Fe-0@black-TiO(2 )were systematically elucidated by multiple characterization techniques. Furthermore, photodegradation pathways of TC based on the role of center dot O-2(-) and center dot OH were identified. Our results have provided the necessary inspiration and guidance for the development and application prospect of Fe0@black-TiO2 in environmental remediation.

Automated summary

This research presents an innovatively designed mechanism to activate the passivation layer on the surface of Fe-0 and construct an in-situ Z-scheme heterojunction for high-efficiency environmental remediation. By facile synthesis of a recyclable Fe0@black-TiO2 Z-scheme heterojunction, both the aggregation and passivation of Fe-0 and the low visible-light absorption of TiO2 were improved simultaneously. The results showed that the degradation efficiency of tetracycline (TC) with Fe0@black-TiO2 was significantly higher than that of pristine Fe-0 and black-TiO2, which can be attributed to the strong reduction ability of highly dispersed Fe-0 and the in-situ constructed Z-scheme heterojunction.