Enhanced visible light photocatalytic activity of g-C3N4 decorated ZrO2-x nanotubes heterostructure for degradation of tetracycline hydrochloride

[Display omitted] •The g-C3N4 decorated ZrO2-x nanotubues heterostructure was successfully constructed.•The separation rate of photo-generated carriers greatly enhanced by the heterojunction.•The charge migration mechanism was studied by in-situ XPS.•The heterojunction exhibited excellent visible light photocatalytic activity. Photocatalytic degradation is considered as a promising strategy to address the environmental threat caused by antibiotics abuse. Visible light driven g-C3N4 decorated ZrO2-x nanotubes heterostructure photocatalysts for antibiotic degradation were successfully synthesized by anodic oxidation and following a thermal vapor deposition method. Compared with pure g-C3N4 or ZrO2-x nanotubes, the composite photocatalysts exhibited more extended visible light response and higher separation rate of photo-generated electron-holes pairs. The optimized heteroctructure with 7.1 wt.% g-C3N4 exhibited 90.6% degradation of tetracycline hydrochloride (TC-H) under 1 h visible light irradiation. The mainly active species of TC-H degradation were photo-generated h+ and O2-. The pathway of charge migration in the g-C3N4/ZrO2-x NTs system was also studied and a possible photocatalytic mechanism was proposed for TC-H degradation. Constructing the g-C3N4/ZrO2-x nanotubes heterostructure is anticipated to be an effective strategy for photocatalytic degradation of antibiotics.