Ox/Red-controllable combustion synthesis of foam-like PrFeO3 nanopowders for effective photo-Fenton degradation of methyl violet

Boosting the catalytic activity of nanostructured ZnFe2O4 spinels incorporating with Cu2+ for photo-Fenton degradation under visible light

Methylene blue (MB) is hazardous in natural water because this dye causes serious diseases that endangers public health and ecosystems. Photocatalytic degradation is a prominent technique for achieving the effective elimination of dye pollutants from wastewater and contribute vitally to ecology and environmental safety. Herein, Cu2+-substituted ZnFe2O4 nanomaterials (CuxZn1-xFe2O4; x = 0, 0.1, 0.2, 0.3, 0.4, 0.6) were synthesized, characterized, and applied for the photocatalytic degradation of MB dye beneath visible light with the assistance of hydrogen peroxide (H2O2). The feature of the photo-catalysts was determined by XRD, EDX, FTIR, DRS, BET, SEM, and TEM techniques. Incorporation of Cu2+ ions changed the crystalline phase, particle size, morphology, and surface area. The photocatalysis condition was optimized with the following major factors, the amout of doping Cu2+ ions, H2O2 concentration, adsorbent dosage, and MB concentration. As a result, the photocatalytic MB degradation efficiency by Cu0.6Zn0.4Fe2O4 catalyst was 99.83% within 90 min under LED light (λ ≥ 420 nm), which was around 4 folds higher than that of pure ZnFe2O4. The photo-Fenton kinetics were in accordance with the pseudo-first-order kinetic model (R2 = 0.981), giving the highes rate constant of 0.034 min-1. It can be, therefore, concluded that Cu2+ substitution considerably boosted the photocatalytic activity of CuxZn1-xFe2O4 ZnFe2O4, suggesting a bright prospect of Cu0.6Zn0.4Fe2O4 as a photo-catalyst in the dyes wastewater treatment.

Cyclic Voltammetry Study and Solar Light Assisted Photocatalytic Activity of the CeFeO3/CeO2/Fe2O3 Composite

The semiconducting nature of CeFeO3/CeO2/Fe2O3 nanocomposite has permitted the degradation of the organic toxic dye methylene blue under the irradiation of ultraviolet and visible light portions of solar radiation. Fullprof-assisted Rietveld refinement analysis, performed using the Match software, has revealed the orthorhombic nature of CeFeO3. In addition, in the synthesized material, the cubic phase byproduct CeO2 was found due to the highly oxidizing nature of the cerium element. This occurred due to 6 min microwave irradiation because the microwave-assisted technique offered random distribution of heating during the supply of 800-W power for 30 s, followed by 12 cycles. Additionally, the presence of Fe2O3 was also confirmed through Match software-assisted Rietveld refinement analysis through phase matching. During the synthesis, a certain portion of the synthesized CeFeO3 experienced overheating, leading to phase transformation from CeFeO3 into Fe2O3 and CeO2. The unit cell compositions of CeFeO3, CeO2, and Fe2O3 were found in the sample material with 35.54%, 52.43%, and 12.03%, respectively. The appearance of a fingerprint absorption region in the FTIR spectrum around 577.36 and 535.38 cm-1 further confirmed the similarity of these values (577.36 and 535.38 cm-1) to those obtained from the calculated values obtained by substituting Rietveld refined bond length parameters. The fourth step process in the thermal analysis curve (TGA) revealed the oxidation process, which led to the destruction of the CeFeO3 phase, causing the transformation of CeFeO3 into two byproducts (CeO2 and Fe2O3). This oxidation process permitted in an observable weight gain, which is observed in the thermal analysis curve (TGA). A cyclic voltammetry study (the experimentally measured current-voltage characteristic curve) revealed slightly distorted semirectangular CV curves, confirming the pseudo-capacitive behavior of the synthesized composite.

Novel g-C3N4/PrFeO3 nanocomposites with Z-scheme structure and superior photocatalytic activity toward visible-light-driven removal of tetracycline antibiotics

In the presented work, heterostructured nanocomposites based on g-C3N4 and PrFeO3 with different mass content of PrFeO3 (0-10 wt%) were prepared by ultrasonic processing to study their photocatalytic activity in the process of antibiotic degradation under visible light. The study of phase composition, structural, morphological and textural characteristics carried out by powder X-ray diffraction, scanning electron microscopy and adsorption-structural analysis confirmed the presence of two phases - graphite-like C3N4 and orthorhombic PrFeO3 with average crystallite sizes of 5 and 21 nm and mesoporous structure with specific surface area of 57.2-68.6 m2/g and average pore size of 20 nm. The measured values of the forbidden bandwidth for the obtained nanocomposites were ∼3 eV, indicating potential activity under visible light irradiation. The efficiency of antibiotic removal under visible light was evaluated in the degradation of TCHCl. It was found that 5 % PrFeO3 content was optimal and increased the TOF by 5 times compared to pure g-C3N4. The results of photocatalytic test with absorbers showed that photocatalysis occurs by Z-scheme mechanism. The results obtained allow us to consider this nanocomposite as an effective and stable photocatalyst for pharmaceutical wastewater treatment.