BiOCl/α-Fe2O3 composite for enhanced photocatalytic degradation of gaseous styrene

Efficiency and mechanism on photocatalytic degradation of fluoranthene in soil by Z-scheme g-C3N4/α-Fe2O3 photocatalyst under simulated sunlight

Polycyclic aromatic hydrocarbons (PAHs) in soil have potential harm on human health. However, remediation of PAH-contaminated soils through photocatalytic technology remains a challenge. Therefore, the photocatalyst g-C₃N₄/α-Fe₂O₃ was synthesized and applied to photocatalytic degradation of fluoranthene in soil. The physicochemical properties of g-C₃N₄/α-Fe₂O₃ and various degradation parameters, such as catalyst dosage, the ratio of water/soil, and initial pH, were investigated in detail. In soil slurry reaction system (water/soil=10:1, w/w), the optimal degradation efficiency on fluoranthene was 88.7% after simulated sunlight irradiation for 12 h (contaminated soil=2 g, initial fluoranthene concentration=36 mg/kg, catalyst dosage=5%, and pH=6.8), and the photocatalytic degradation followed pseudo-first-order kinetics. The degradation efficiency of g-C₃N₄/α-Fe₂O₃ was higher compared with P25. Degradation mechanism analysis showed that •O₂^- and h⁺ are the main active species in photocatalytic degradation process of fluoranthene by g-C₃N₄/α-Fe₂O₃. Coupling g-C₃N₄ and α-Fe₂O₃ enhances the interfacial charge transport capacity via Z-scheme charge transfer route and inhibits the recombination of photogenerated electrons and holes of g-C₃N₄ and α-Fe₂O₃, then significantly improves the production of active species and photocatalytic activity. Results showed that photocatalytic treatment of soil by g-C₃N₄/α-Fe₂O₃ is an effective strategy for remediation of soils contaminated by PAHs.

Construction of SrTiO3-BiOCl composite catalyst via facial microwave hydrothermal for highly efficient photocatalytic activity towards organic compounds degradation

This work mainly focuses on the preparation and performance study of SrTiO₃-BiOCl composite photocatalysis. The SrTiO₃-BiOCl photocatalysts are prepared via the facial microwave hydrothermal method. XRD, UV-vis DRS, SEM, TEM, XPS, N₂ adsorption and desorption isothermal experiment, FT-IR, and PL are applied to characterize the prepared samples. The spherical particles of SrTiO₃ grow on the flaky BiOCl, and the crystal size is uniform and evenly disperses on the BiOCl. The catalytic performance of the samples was evaluated over the degradation rates of methylene blue(MB). Typically, the clearance rates of MB reached to 99.65% over SrTiO₃-BiOCl-50% under visible light, which was much higher than that of SrTiO₃ and BiOCl (55.86%, 79.79%, respectively). The active species capturing experiments and ESR showed that the holes (h⁺) and ·OH are playing the main roles in the degradation process.