Superb photocatalytic H2 production/tetracycline pollutant degradation by synthesizing novel and recyclable ternary g-C3N4-based photocatalyst: Characterization/optimization/mechanism/toxicity assessment

Solar-driven photocatalysis depicts an effective efficiency for producing hydrogen via water splitting, as well as for CO2 reduction and the degradation of hazardous pollutants in aqueous environment, playing a vital role in addressing the challenges associated with the environmental and energy crises. This study presents a synthesis of a Strontium Titanate/Zinc Oxide/Graphitic Carbon Nitride photocatalyst via an integrated sonochemical and wet impregnation method. The photocatalytic efficiency of various content (10 %, 20 %, 30 %, and 40 % wt%) of 40 wt% Titanate/Zinc Oxide loaded on Graphitic Carbon were investigated, with the 30 % loading demonstrating optimal performance. A complete identification of the synthesized materials was carried out using XPS, XRD, BET, TEM, DRS, SEM, EIS, Photocurrent, ESR, PL, and Mott–Schottky analyses. The BET scrutiny indicated a type IV isotherm with H2 hysteresis, representing a mesoporous construction. The improved photocatalytic activity of optimized composite was due to its structural features facilitating efficient electron-hole separation and charge transfer. RSM optimization identified the key parameters for achieving high Cefixime (CFX) degradation efficiency (96 %) at 29.91 mg/L CFX concentration, pH 4.55, 78 min of reaction time, and 0.65 g/L catalyst dosage. LC-MS analysis unveiled two proposed pathways for CFX photodegradation, and trapping experiments and ESR analysis highlighted superoxide and hydroxyl radicals as significant contributors. The synthesized photocatalyst exhibited excellent stability and reusability over five cycles. Hydrogen production showed an initial increase with Strontium Titanate/Zinc Oxide loading, peaking at 645.62 μmol g−1 h−1 at 30 wt%, before declining due to potential electron trapping effects. Notably, the SrZg-30 photocatalyst demonstrated a significantly higher CO production rate (0.97 μmol g−1 h−1) compared to SrTiO3/ZnO and g-C3N4 components. This work offers a viable approach to developing eco-friendly photocatalysts to tackle pressing environmental and energy crises. [Display omitted] •A novel and versatile ternery SrTiO₃/ZnO/gC₃N₄ photocatalyst was synthesized.•Optimizing the influence of effective factors on CFX photodegradation by RSM-CCD.•SrTiO₃/ZnO/gC₃N₄ had excellent photocatalytic in H2 production/CO2 reduction.•Efficient separation of photogenerated carriers boosted the activity of SrZg-30.•Various contents of STZ on the gC₃N₄ were investigated for the first time.