Improved photocatalytic oxidation of ciprofloxacin by NiS-coupled WO3 nanorods synthesized by solvothermal method under visible light

Abstract

Photocatalytic oxidation of antibiotics over semiconducting nanostructured photocatalysts is stared as a capable procedure for preventing possible antimicrobial resistance. Accordingly, plenteous research suggestions for photocatalyst design and trials are investigated to realize this approach. Moreover, photostability and reusability are important factors for sustainable utilization. Herein, tungsten trioxide (WO3) nanorods were grown by a solvothermal route in the presence of double soft templates, followed by incorporating nickel sulfide (NiS) nanoparticles on their surface to have NiS/WO3 nanocomposite photocatalysts. These formed heterojunctions were analyzed via several tools. The NiS incorporation has widened the visible-light harvesting owing to the bandgap reduction from 2.82 eV for pure WO3 to 2.40 eV at 9 wt% of NiS. The mesoporous surface has not been meaningfully impacted by incorporating NiS with a value of the surface area between 163 and 189 m2 g-1. The photooxidation of ciprofloxacin (CiP) over the formed photocatalysts were done under visible-light irradiation. The 2.0 g L-1 of 9% NiS/WO3 has completely oxidized 30.2 μmol CiP at a 1.38 μmol min−1. This progressive NiS/WO3 p-n heterojunction has also implied reusability for five repetitive cycles. This excellent photoactivity is ascribed to the charge transfer by the S-scheme mechanism and the synergistic upshot of a particular NiS expanse.