Towards the Development of a Z-Scheme FeOx/g-C3N4 Thin Film and Perspectives for Ciprofloxacin Visible Light-Driven Photocatalytic Degradation

Thermally synthesized graphitic carbon nitride (g-C3N4) over pulsed laser deposition (PLD) produced urchin-like iron oxide (FeOx) thin films were fabricated via in situ and ex situ processes. Materials characterisation revealed the formation of the graphitic allotrope of C3N4 and a bandgap E-g for the combined FeOx/g-C3N4 of 1.87 and 1.95 eV for each of the different fabrication strategies. The in situ method permitted to develop a novel petal-like morphology, whereas for the ex situ method, a morphological mixture between FeOx bulk and g-C3N4 was observed. Given the improved optical and morphological properties of the in situ film, it was employed as a proof of concept for the direct photocatalysis and photo-Fenton removal of ciprofloxacin antibiotic (CIP) under visible light irradiation. Improved photocatalytic activity (rate constant k = 8.28 x 10(-4) min(-1)) was observed, with further enhancement under photo-Fenton conditions (k = 2.6 x 10(-3) min(-1)), in comparison with FeOx + H2O2 (k = 1.6 x 10(-3) min(-1)) and H2O2 only (k = 1.3 x 10(-4) min(-1)). These effects demonstrate the in situ methodology as a viable route to obtain working heterojunctions for solar photocatalysis in thin-film materials, rather than the more common powder materials.

Automated summary

Thermally synthesized graphitic carbon nitride combined with pulsed laser deposition led to the fabrication of urchin-like iron oxide thin films, showing improved photocatalytic activity under visible light irradiation for the removal of ciprofloxacin antibiotic. The in situ methodology demonstrated the potential to obtain working heterojunctions for solar photocatalysis in thin-film materials, showcasing a novel petal-like morphology.