Bifunctional Fe active sites on carbon nitride and titanium-based 2D nanomaterials for efficient visible light-driven ciprofloxacin degradation and overall water splitting

The soft magnetic FeS 2 /Fe 2 O 3 (FeS/FeO)-incorporated 2D C 3 N 4 and TiO 2-x nanomaterials were successfully synthesized and characterized by various physicochemical techniques, including XRD, FTIR, XPS, HRTEM, UV - Vis, VSM-magnetism and PL. The photocatalytic performance of the materials was applied to activate potassium persulfate (PPS) and H 2 O 2 for the antibiotic ciprofloxacin (CIP) degradation as well as for water splitting using the photoelectrochemical path. The results illustrated that the degradation efficiency of the best photocatalyst, FeS/FeO@10 %2DTiO 2-x , was 90 % in the presence of PPS and 100 % in the case of H 2 O 2 , with rate constants equal to 12.1 x 10 -3 min - 1 and 17.6 x 10 -3 , respectively, at an optimized reaction condition of 100 ml of 20 ppm CIP, H 2 O 2 = 1.7 x 10 -4 M, PPS = 1 x 10 -3 M, catalyst = 0.1 g, pH = 3.5, t = 180 min, and at r.t. The exceptional activity of FeS/FeO@10 %2DTiO 2-x compared to other nanocomposites may be attributed to the efficient exciton separation via the Z-scheme transferring pathway and the continuous Fe 2+ and Fe 3+ shuttles that support the photoFenton activity. Numerous examinations, including those on toxicity, zero -point charge, total organic carbon, temperature and the suggested mechanism, are well evaluated and discussed. The FeS/FeO@4%TiO 2 black-C 3 N 4 photoelectrocatalyst exhibited excellent HER capacities in neutral medium, with overpotentials of -0.546 V at 10 mA cm -2 whereas for OER it shows overpotentials of 1.09 V mV at 10 mA cm -2 . It showed 1.65 V of cell voltage at 10 mA cm -2 , while maintaining 80 % stability. Interestingly, the latter electrode ' s high efficiency can be attributed to a variety of factors, including variations in spectral light absorption, a longer lifespan for photogenerated electron-hole pairs, a better charge transfer efficiency, and the integration of Ti 3+ and O v generated from Ti -black with C 3 N 4 .