Ag3PO4 Deposited on CuBi2O4 to Construct Z-Scheme Photocatalyst with Excellent Visible-Light Catalytic Performance Toward the Degradation of Diclofenac Sodium

Highly efficient degradation of ofloxacin and diclofenac by composite photocatalyst aloe-emodin/PMMA

Photocatalysis is one of the most effective methods to remove pollutants from water. Photocatalyst is the core of photocatalysis. The composite photocatalyst combines the photosensitizer with the support and uses the photosensitivity of the photosensitizer and the stability and adsorption of the support to achieve efficient and rapid degradation of pharmaceuticals in water. In this study, natural aloe-emodin with π-conjugated structure was used as photosensitizer to react with macroporous resin polymethylmethacrylate (PMMA) under mild conditions to prepare composite photocatalysts AE/PMMAs. The photocatalyst underwent photogenerated electron migration under visible light to form ^•O₂^- and holes with high oxidation activity, which could realize efficient photocatalytic degradation of ofloxacin and diclofenac sodium and showed excellent stability, recyclability and industrial feasibility. This research has developed an efficient method of composite photocatalyst and realized the application of a natural photosensitizer in pharmaceutical degradations.

Novel visible-light-driven SrCoO3/Ag3PO4 heterojunction with enhanced photocatalytic performance for tetracycline degradation

The semiconductor photocatalytic technology has been considerably studied due to its excellent catalytic performance in water pollution control. Herein, in this study, novel SrCoO₃/Ag₃PO₄ composite materials with different SrCoO₃ content were synthesized via a simple hydrothermal synthesis method. The characteristics of the as-prepared samples were detected through SEM/HRTEM, XRD, UV-vis DRS, PL, ESR, FT-IR, and XPS techniques, and then, the photocatalytic performance of SrCoO₃/Ag₃PO₄ toward the degradation of tetracycline was investigated. When the mass ratio of SrCoO₃ and Ag₃PO₄ in the composite was 1:1.5, the degradation rate constant of tetracycline in SrCoO₃/Ag₃PO₄ (1:1.5) system is 0.0102 min^-1, which is 1.7 times that of the Ag₃PO₄, and 3.78 times that of the SrCoO₃. In addition, reactive species were also analyzed through the free radical trapping experiment and DMPO spin-trapping ESR spectra analysis, showing that OH^•, h⁺, and O₂^•-participated in the catalytic degradation process of tetracycline to varying degrees. Finally, the photocatalytic mechanism of SrCoO₃/Ag₃PO₄ was also proposed.

A ternary CdS/AgBr/Ag3PO4 nanocomposite: characterization and the kinetics of its photocatalytic activity

A ternary CdS/AgBr/Ag₃PO₄ coupled system was prepared, characterized by different techniques, and used for the photodegradation of methylene blue (MB). The hexagonal (wurtzite) CdS, the cubic AgBr, and the Ag₃PO₄ body-centered cubic crystallite phases were detected by XRD patterns. The Scherer equation showed the crystallite sizes of 3, 26.3, 28, and 27.9 nm for CdS, Ag₃PO₄, AgBr NPs, and the ternary CdS/AgBr/Ag₃PO₄ sample, while the Williamson-Hall model got the values of 1.8, 46.2, 62.12, and 92.44 nm, respectively. The diffuse reflectance spectra (DRS) showed that the ternary catalyst could absorb the whole range of visible light photons. The photoluminescence (PL) spectra significantly depended on the solvent nature, and the sharp scattering peaks appeared in the water, while these were absent in acetone as solvent. The ternary catalyst also showed a lower PL intensity and a higher photocatalytic activity concerning the individual NPs. When the moles of CdS were three times greater than the other components, the resulted ternary catalyst showed the lowest PL intensity and the highest degradation activity. The MB mineralization was also studied by the COD technique and compared with MB photodegradation kinetically. The MB photodegradation rate constant of about 0.0276 min^-1 (correspond to t_1/2 25.1 min) was 1.75 times greater than the MB mineralization rate constant (about 0.0158 min^-1 correspond to t_1/2 value of 43.9 min).

The application of FTO-Cu2O/Ag3PO4 heterojunction in the photoelectrochemical degradation of emerging pharmaceutical pollutant under visible light irradiation

We report the photoelectrochemical application of a visible light active FTO-Cu₂O/Ag₃PO₄ photoanode for the abatement of sulfamethoxazole in water. The as-synthesised photoanodes were characterised using XRD, field emission SEM, EDX, diffuse reflectance UV-vis, impedance spectroscopy and chronoamperometry. The results obtained confirmed a successful formation of p-n heterojunction at the Cu₂O/Ag₃PO₄ interface. The highest photocurrent response of 0.62 mAcm^-2 was obtained for the composite photoanode which was four times higher than pure Cu₂O and about three times higher than pristine Ag₃PO₄. The photoanode gave 67% removal efficiency within 2 h upon its photoelectrochemical application in the degradation of sulfamethoxazole with 1.5 V bias potential at pH 6.2. The FTO-Cu₂O/Ag₃PO₄ electrode was also applied in the treatment of a cocktail of synthetic organics containing sulfamethoxazole and orange II dye. The photogenerated holes was found to be the major oxidant and the photoanodes was stable and reusable.

Selective oxidation of alcohols by using CoFe2O4/Ag2MoO4 as a visible-light-driven heterogeneous photocatalyst

Using a CoFe₂O₄/Ag₂MoO₄ heterostructure as a novel, stable, inexpensive, and reusable photocatalyst with high-performance for the oxidation of alcohols.

Short-Time Hydrothermal Synthesis of CuBi2O4 Nanocolumn Arrays for Efficient Visible-Light Photocatalysis

In this article, a short-time hydrothermal method is developed to prepare CuBi₂O₄ nanocolumn arrays. By using Bi(NO₃)₃·5H₂O in acetic acid and Cu(NO₃)₂·3H₂O in ethanol as precursor solutions, tetragonal CuBi₂O₄ with good visible light absorption can be fabricated within 0.5 h at 120 °C. Tetragonal structured CuBi₂O₄ can be formed after 15 min hydrothermal treatment, however it possesses poor visible light absorption and low photocatalytic activity. Extending the hydrothermal treatment duration to 0.5 h results in a significant improvement invisible light absorption of the tetragonal CuBi₂O₄. The CuBi₂O₄ obtained through 0.5 h hydrothermal synthesis shows a band gap of 1.75 eV and exhibits the highest photocatalytic performance among the CuBi₂O₄ prepared with various hydrothermal time. The removal rate of methylene blue by the 0.5 h CuBi₂O₄ reaches 91% under visible light irradiation for 0.5 h. This study proposes a novel strategy to prepare photoactive CuBi₂O₄ nanocolumn arrays within 0.5 h at a moderate temperature of 120 °C. The hydrothermal method provides a facile strategy for the fast synthesis of metal-oxide-based photocatalysts at mild reaction conditions.