Designing Oxygen Vacancy Mediated Bi2moo6/C3n5 S-Scheme Heterojunctions for Boosted Photocatalytic Removal of Tetracycline Antibiotic and Cr(Vi) : Intermediate Toxicity and Mechanism Insight

Polymeric carbon nitride of C3N5 is being utilized as a new visible-light-driven catalyst due to its narrower bandgap (~ 2.0 eV). Building step-scheme (S-scheme) heterojunction by coupling with other semiconductors especially those own oxygen vacancies (OVs) can further upgrade the photocatalytic performance of C3N5-based photocatalysts. Herein, a novel S-scheme heterojunction of OVs mediated Bi2MoO6/C3N5 was fabricated by in-situ growing Bi2MoO6 nanoparticles with OVs on C3N5 nanosheets. Benefiting from the efficient separation and transfer of high energetic charge carriers by S-scheme charge migration, enriched structural defects, as well as the close contact by the in-situ growth, the heterojunction exhibited superior visible-light photocatalytic performance toward the removal of tetracycline (TC) and Cr(VI) than C3N5, Bi2MoO6, and their mechanical mixture. The TC degradation routes based on the degradation intermediates identified by HPLC–MS and the toxicity evolution of TC evaluated by using the QSAR method were explored. Moreover, the photocatalytic mechanism for TC decomposition and Cr(VI) reduction over Bi2MoO6/C3N5 with OVs was elucidated. This work presents a newfangled vision for designing promising C3N5-based S-scheme heterojunction photocatalysts for pollution control