Crumpled sheet like graphene based WO3-Fe2O3 nanocomposites for enhanced charge transfer and solar photocatalysts for environmental remediation

The combination of two or more metal oxides onto graphene sheets with even distribution is projected to enhanced charge transfer properties in photocatalytic applications. We report, tungsten oxide (WO3) with iron oxide (Fe2O3) nanoparticles grown on graphene sheets via a facile economical one pot hydrothermal method and consequently characterized by standard analytical techniques. Synthesized Fe2O3 with WO3 nanoparticles were well ornamented on surface of the graphene sheets which have a significant charge transfer properties. The resulting hybrid WO3-Fe2O3-rGO (WFG) nanocomposites showed enhanced photocatalytic, heavy metal removal and antibacterial activities. The superior photocatalytic removal efficiencies were observed for the removal of rhodamine B (∼94%) and methylene blue dyes (∼98%) under solar light irradiation. The antibacterial activity of WFG nanocomposites were performed against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) as models for Gram-negative and Gram-positive bacteria. The outcome of the results have an intellectual effect on the use of WFG nanocomposites to address the upcoming energy and environment issues

Green synthesis of CeO2–TiO2 compound using Cleome chelidonii leaf extract for excellent photocatalytic activity

A facile novel green synthesis of cerium oxide doped titanium dioxide (CeO2–TiO2) nanocompound was prepared using Cleome chelidonii leaf extract as the reducing agent and was investigated for the photodegradation of dyes under UV light irradiation. The synthesized compounds are characterized by X-Ray Diffraction, Raman spectroscopy, UV and FL spectroscopy, XPS, FESEM and TEM. The results signify that the prepared materials show superior results compared to bare TiO2 and CeO2 particles due to alternation in the bandgap, surface area adsorption and enhanced photo-responsive were played a vital role in performing the degradation activity. Incorporation of CeO2 into TiO2 controls the higher recombination of electron–hole and acting as electron supporter for creating more cation/anion and additionally, the higher amount of oxygen content in CeO2 leads an advantage in degradation of dyes which shields the valency bands which reduce the recombination

Phyto-fabrication of AgNPs using leaf extract of Vitex trifolia: potential to antibacterial, antioxidant, dye degradation, and their evaluation of non-toxicity to Chlorella vulgaris

The study assessed the bactericidal effects of green rapid biogenic synthesis of Vitex trifolia leaves AgNPs on MDR bacteria. The synthesis of AgNPs is indicated by a color change from yellow to dark brown. The ultra-visible spectrophotometer displays AgNPs at 430 nm max. This demonstrates that ions (Ag+) were converted to silver (Ag), indicating the formation of silver nanoparticles. The synthesized nanoparticles were confirmed by their crystalline nature, shape, size, and functional groups via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X- ray spectroscopy (EDAX), and transmission electron microscopy (TEM). Biomolecules contain aqueous Vitex extract for capping and reducing the AgNPs. The nanoparticles have a face-centered cubic structure (FCC) crystallized. The antibacterial activity against Staphylococcus aureus, Vibrio cholerae, and Klebsiella pneumoniae exhibited a maximum zone of growth inhibition at 75 µg/mL. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against the clinically isolated pathogen S. aureus were 3.12 µg/mL and 4.5 µg/mL. Furthermore, time-dependent killing kinetic experiments showed that a 6 h AgNPs treatment was sufficient to fully inhibit all bacterial growth. AgNPs at a concentration of 250 µg/mL demonstrated antioxidant activity as measured by the FRAP and DPPH tests (85% and 90%, respectively). AgNPs demonstrated efficient photocatalytic activity in the degradation of methylene blue (MB) and achieved their highest photocatalytic activity (95%) after 2.30 h. Besides, the synthesis of AgNPs was targeted towards C. vulgaris algae, and exhibited deleterious effects even at larger concentrations. The chosen AgNPs concentration reduced chlorophyll, impeded algal development, and damaged the whole membrane system, as evidenced by the increased electrolyte leakage and malondialdehyde (MDA) and glutathione s-transferase (GSH) content after AgNPs exposure. Our report demonstrates that AgNPs V. trifolia have promising antibacterial, antioxidant, and potential dye degradation activities and can be employed in biomedical applications.</p