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.