Design of V2O5 Blocks Decorated with Garlic Peel Biochar Nanoparticles: A Sustainable Catalyst for the Degradation of Methyl Orange and Its Antioxidant Activity.

In this study, novel V2O5-decorated garlic peel biochar (VO/GPB) nanocomposites are prepared via the facile hydrothermal technique. As-synthesized VO/GPB is characterized by various spectroscopic and analytical techniques. The surface morphology of the as-prepared samples was predicted by SEM analysis, which shows that the block-like V2O5 was uniformly decorated on the stone-like GPB surface. The elemental mapping analysis confirms the VO/GPB composite is composed of the following elements: C, O, Na, Mg, Si, P, K, and V, without any other impurities. The photocatalytic activity of the VO/GPB nanocomposite was examined by the degradation of methyl orange (MO) under the irradiation of visible light; 84% degradation efficiency was achieved within 30 min. The reactive oxidative species (ROS) study reveals that hydroxyl and superoxide radicals play an essential role in MO degradation. Moreover, the antioxidant action of the VO/GPB nanocomposite was also investigated. From the results, the VO/GPB composite has higher antioxidant activity compared to ascorbic acid; the scavenging effect increased with increasing concentrations of VO/GPB composite until it reached 40 mg/L, where the scavenging effect was the highest at 93.86%. This study will afford innovative insights into other photocatalytic nanomaterials with effective applications in the field of photocatalytic studies with environmental compensation.

New reductant-free synthesis of gold nanoparticles-doped chitosan-based semi-IPN nanogel: A robust nanoreactor for exclusively sensitive 5-fluorouracil sensor.

We report a novel class of chitosan (CS)-based hybrid semi-interpenetrating nanogel catalyst by the reductant-free green synthesis of gold nanoparticles (Au NPs) within the CS-poly(methacrylic acid) (Au@CS-PMAA) polymer network. The covalently cross-linked Au@CS-PMAA nanogel with CS chains semi-interpenetrating (semi-IPN) in the PMAA cross-linked network show superior colloidal stability and improved catalytic activity. The synthesized Au@CS-PMAA semi-IPN nanogel was applied as a superior modifier to create a new and sorely selective electrochemical sensing platform for the determination of antileukemic drug 5-fluorouracil (5-FU). The existence of -OH and -COOH groups in the CS and PMAA offers numerous binding sites for 5-FU. This assures the incorporation of Au NPs which affords a larger surface area and ameliorate electrical conductivity. Besides, the synergic effect amid both compounds improves the detection of 5-FU. Under optimal conditions, the constructed sensor offered a good performance in determination of 5-FU with a wide linear range from 0.1-497 µM and low detection limits of 0.03 µM, respectively. Further, this study proved that the fabricated sensor could be useful for analysis of 5-FU in actual human blood serum samples.