Boosting visible-light-promoted photodegradation of norfloxacin by S-doped g-C3N4 grafted by NiS as robust photocatalytic heterojunctions

As a result of industrial expansion and ill-considered exploitation of resources, serious environmental issues have recently emerged that have led to damage to the ecosystem. In particular, antibiotics, such as norfloxacin (NOR) have emerged as highly hazardous contaminants resulting from the increased use of these drugs worldwide. Photocatalysis-based degradation using heterojunctions has become almost the only way to permanently and eco-friendly degrade these pollutants. Herein, noble metal-free nanohybrids composed of S-doped g-C3N4 grafted by NiS (denoted as NiS/SCN) have been fabricated via hydrothermal and one-step polymerization (at 550 °C) procedures. The photocatalytic activity of 3%NiS/SCN photocatalyst was almost 6- and 20-times as high as SCN and NiS, respectively, achieving 96.2% NOR degradation within 90 min. The recommended photocarriers transfer pathway was suggested and supported experimentally. Considerably, loading a small amount of NiS cocatalyst over S-doped g-C3N4 boosted performance in addition to efficient reusability. This increased photocatalytic activity can be attributed to the fact that doping g-C3N4 with sulfur can reduce the bandgap and thus broaden the response range to visible-light, and the effective effect of Schottky junction can significantly improve the separation rate of electron-hole pairs. Accordingly, the constructed NiS/SCN nanocomposites are potential candidates for photocatalysis processes, particularly visible-light-induced degradation of organic pollutants.