Establishing photocatalysis-self-Fenton system over a S-scheme Fe/Fe2O3@CuBi2O4 for enhancing TC removal via in-situ generating H2O2 and Fe/Cu dual-metal electron cycle: Radical and non-radical pathways

A S-scheme Fe/Fe 2 O 3 @CBO photocatalyst was synthesized via a grinding calcination method, proficiently degrading tetracycline via radicals and non-radical. The reaction rate of Fe/Fe 2 O 3 @CBO-20 was recovered to 0.0255 min −1 that is 4.3 and 7.3 times as many as pristine Fe/Fe 2 O 3 and CBO after introducing visible light at the degradation process. The characterization outcomes also bear out that the S-scheme heterojunction is formed by passivation layer Fe 2 O 3 and CBO, which enhances the visible light responsiveness of catalyst and promotes the separation and transfer of photogenerated electrons to generate h + and O 2 − . Meanwhile, the molecular oxygen is more easily activated to form H 2 O 2 due to the strong reduction potential of the CB (−1.21 eV), further to facilitate the transformation of O 2 − to 1 O 2 . And the carriers excited in CBO activate Cu + , forming a Cu/Fe dual-metal electron cycle. The generated Fe 2+ reacts with H 2 O 2 to establish photocatalysis-self-Fenton system to generate ·OH. Additionally, the high TC removal in simulated aquatic environment exhibit that the catalytic performance is slightly affected by practical wastewater and the cyclic experiment show the stability and practicality. In conclusion, innovatively employing Fe/Fe 2 O 3 for pollutant degradation via photocatalytic technology, this research paves a promising and efficacious pathway for the application of Fe/Fe 2 O 3 .