Ultrasound-assisted construction of a Z-scheme heterojunction with g-C3N4 nanosheets and flower-like Bi2WO6 microspheres and the photocatalytic activity in the coupling reaction between alcohols and amines under visible light irradiation

Development of Sulfur-Doped Graphitic Carbon Nitride for Hydrogen Evolution under Visible-Light Irradiation

Developing eco-friendly strategies to produce green fuel has attracted continuous and extensive attention. In this study, a novel gas-templating method was developed to prepare 2D porous S-doped g-C₃N₄ photocatalyst through simultaneous pyrolysis of urea (main g-C₃N₄ precursor) and ammonium sulfate (sulfur source and structure promoter). Different content of ammonium sulfate was examined to find the optimal synthesis conditions and to investigate the property-governed activity. The physicochemical properties of the obtained photocatalysts were analyzed by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), scanning transmission electron microscopy (STEM), specific surface area (BET) measurement, ultraviolet-visible light diffuse reflectance spectroscopy (UV/vis DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and reversed double-beam photo-acoustic spectroscopy (RDB-PAS). The as-prepared S-doped g-C₃N₄ photocatalysts were applied for photocatalytic H₂ evolution under vis irradiation. The condition-dependent activity was probed to achieve the best photocatalytic performance. It was demonstrated that ammonium sulfate played a crucial role to achieve concurrently 2D morphology, controlled nanostructure, and S-doping of g-C₃N₄ in a one-pot process. The 2D nanoporous S-doped g-C₃N₄ of crumpled lamellar-like structure with large specific surface area (73.8 m² g^-1) and improved electron-hole separation showed a remarkable H₂ generation rate, which was almost one order in magnitude higher than that of pristine g-C₃N₄. It has been found that though all properties are crucial for the overall photocatalytic performance, efficient doping is probably a key factor for high photocatalytic activity. Moreover, the photocatalysts exhibit significant stability during recycling. Accordingly, a significant potential of S-doped g-C₃N₄ has been revealed for practical use under natural solar radiation.

New and highly efficient Ultra-thin g-C3N4/FeOCl nanocomposites as photo-Fenton catalysts for pollutants degradation and antibacterial effect under visible light

The photo-Fenton reaction was widely used in the removal of pollutants in waste water, which makes it exhibit great potential in the field of environmental remediation. Hence, it is crucial to explore a new efficient and stable photo-Fenton catalyst driven by visible light. In this work, a simple two-step calcination method was used to synthesize sheet-like stacked Ultra-thin g-C₃N₄/FeOCl (CNF) materials. The morphology, composition, photo-Fenton performance, and antibacterial properties were systematically analyzed. Research results exhibited that the synthesized CNF catalysts showed enhanced visible light absorption capacity and excellent photo-Fenton performance. Compared with FeOCl alone, CNF displayed stronger degradation ability for rhodamine B (RhB) and could achieve 97% degradation within 9 min, which was about 10 times that of pure FeOCl. At the same time, the composite catalysts exhibited excellent antibacterial effects under photo-Fenton conditions. The antibacterial rate of CNF composite catalyst under photo-Fenton conditions can reach almost 99%, which was 3 times that of photocatalysis alone and 2 times that of Fenton alone. The heterojunction formed between Ultra-thin g-C₃N₄ and FeOCl promoted the separation of e^- and h⁺. Simultaneously, the presence of e^- promoted the cycle of Fe³⁺ and Fe²⁺ in FeOCl, thereby promoting the generation of hydroxyl radicals (OH) from H₂O₂ and improving the photo-Fenton activity to achieve the effect of degrading pollutants and antibacterial. The photo-Fenton catalysis and degradation mechanism were analyzed in detail. This work provided a theoretical basis for the application of CNF material in the removal of wastewater.