Bavani Thirugnanam

The current study used a green synthesis process to synthesize nickel oxide nanoparticles (NiO NPs) using flower extract from Azadirachta indica . The FTIR spectrum, XRD, UV–vis, FESEM & EDX, and TEM with SAED analysis were used to characterize the structural, optical, morphological, and elemental analyses. The UV–vis absorption spectrum of the NiO NPs exhibited a prominent absorption peak at 290 nm. The FESEM exhibited an almost spherical shape with 50 nm size. The TEM studies showed spherical‐shaped particles with an average size of approximately 100 nm. After 24 h of incubation at 37°C NiO NPs revealed antibacterial activity with a maximum zone of inhibition of 29.64 ± 0.30 mm against Escherichia coli at 75 µL and dose‐dependently decreased bacterial growth. Although concentration of NPs increased from 25 µg/mL to 500 µg/mL after 72 h, cytotoxic investigations show a significant reduction in proliferation of breast cancer MCF7 cells. Furthermore, AI ‐NiO NPs exhibited photocatalytic activity of degrading methylene blue dye by 83% over 150 min under UV–visible light. In perspective of the above result, we essentially propose that the use of a more sustainable method to synthesize NiO NPs for breast cancer and related infections could be effectively treated.

To address the bottleneck issue of poor carrier separation and transfer efficiency in NiCo₂O₄ photocatalyst, a novel 1D/2D-rod-on-rose–like NiCO₂O₄/BiOI nanohybrid with abundant OV’s was successfully synthesized using a single-step hydrothermal method and employed to the photocatalytic degradation of Rhodamine B (RhB). The study revealed that the optimized NiCo₂O₄-OV/BiOI hybrid could possess superior photocatalytic degradation efficiency towards RhB degradation under visible light with a rate constant that was 3.8 and 3.03 times greater than that of BiOI and NiCo₂O₄-OV. Experimental findings indicated that the formation of NiCo₂CO₄-OV/BiOI heterojunction significantly improved the charge separation efficiency and facilitated the formation of surface OV’s. These OVs enhanced photogenerated e⁻-h⁺ separation and increased catalytic efficiency. Quenching experiments results confirmed that both holes and superoxide radicals are playing crucial roles in the degradation process. Thus, an oxygen vacancy and engineering NiCo₂CO₄-OV/BiOI heterojunction-enhanced degradation mechanism was proposed, offering insights for the integration of advanced oxidation technologies and the development of catalytic materials to enhance pollutant degradation efficiency. Graphical abstract

This study describes the microwave assisted synthesis of without and with sodium hexametaphosphate (SHMP) (1 mol%) capped 3 mol% Ni- doped ZnO nanoparticles. Various sophisticated analytical techniques were used to characterize the Ni-doped ZnO nanoparticles. The results showed that including SHMP capped 3 mol% Ni-doped ZnO nanoparticles has a significant influence on the photoctalyst and structural characteristics of the ZnO nanoparticles. Under visible light illumination, SHMP capped 3 mol% Ni-doped ZnO nanoparticles demonstrated better photocatalytic degradation of methylene blue dye. As a result, SHMP capped 3 mol% Ni-doped ZnO nanoparticles synthesized are suitable materials for the environmental applications.

There is a growing demand for efficient methods to decrease hazardous organic contaminants in wastewater. Herein, a novel S‐scheme WS₂/BiOI heterojunction photocatalyst was prepared by a one‐pot solvothermal process. The structural morphology, crystal structure and optical absorption studies were studied. The sugar‐like nanocrystals of WS₂ are deposited on 3D‐BiOI marigold flowers, providing high surface area with increased visible light absorption. The photocatalytic activity of the synthesized materials was studied by visible light degradation of Rhodamine‐B (RhB). The optimized 20 wt.% WS₂ in the composite photocatalyst (band gap 2.25 eV) exhibited a 98.9 % photocatalytic degradation activity with a rate constant of 0.0940 min⁻¹ with performance retained after 3 consecutive recycling runs. Photoelectrochemical studies revealed excellent stability, increased separation and migration ability of charge carriers with lower charge resistance in the optimized WS₂/BiOI photocatalyst.

NiMoO₄/g-C₃N₄ was fabricated by a hydrothermal method and used as an electrode material in a supercapacitor. The samples were characterized by XRD, FTIR, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study the physical and structural properties of the as-prepared NiMoO₄/g-C₃N₄ material. The electrochemical responses of pristine NiMoO₄ and the NiMoO₄/g-C₃N₄ nanocomposite material were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). From the CD studies, the NiMoO₄/g-C₃N₄ nanocomposite revealed a higher maximum specific capacitance (510 Fg⁻¹) in comparison to pristine NiMoO₄ (203 Fg⁻¹). In addition, the NiMoO₄/g-C₃N₄ composite electrode material exhibited high stability, which maintained up to 91.8% capacity even after 2000 charge-discharge cycles. Finally, NiMoO₄/g-C₃N₄ was found to exhibit an energy density value of 11.3 Whkg⁻¹. These findings clearly suggested that NiMoO₄/g-C₃N₄ could be a suitable electrode material for electrochemical capacitors.