This study consists of a reliable process for synthesizing ZnO NPs by green method. Here, Eucalyptus globulus Labill. leaf extract is utilized as an efficient chelating and capping agent for synthesizing ZnO NPs from zinc nitrate hexahydrate salt. The plant ingredients, structure, morphology, thermal behavior, chemical composition and optical properties of ZnO nanoparticles were investigated using several characterization techniques, namely XRD, FE-SEM, EDX, BET, Zeta potential, DLS, differential scanning calorimetry (DSC) analysis, FT-IR analysis and UV–Vis spectroscopy. The UV–Vis and FTIR analysis of Eucalyptus globulus leaf extract verified that this extract is a promising candidate for biosynthesizing ZnO NPs. The XRD spectrum, DLS and the SEM images confirmed the crystallinity and the spherical-shape of the ZnO NPs with an average size between 27 and 35 nm. The band-gap of the ZnO were measured to be around 2.67 eV. Zeta potential and BET analysis showed that, the biosynthesized ZnO NPs possess good stability and the their specific surface area is 23.481 m²/g. DSC analysis exhibits two endothermic peaks related to the water evaporation absorbed by the NPs and modification of zinc complex to zinc hydroxide, with a single exothermic peak related to the crystallization of ZnO NPs and degradation of organic materials.

The electrodeposition of chromium is a technologically vital process, which is principally carried out using aqueous chromic acid. In the current study, it is shown that eutectic mixtures of urea and hydrated chromium(III) chloride provide a liquid which reduces the toxicological issues associated with the current aqueous Cr(VI) electroplating solution. Using EXAFS, mass spectrometry and UV-Vis spectroscopy, it is shown that chromium is present predominantly as a cationic species. Conductivities are higher than for most comparable ionic liquids. It is shown that the electrodeposition of chromium is electrochemically reversible, with a current efficiency much higher than in aqueous electrolytes. Surface tension and density measurements indicate that hole theory is a valid model to describe transport properties in these liquids. Bulk Cr deposits are not macrocrystalline but they are generally crack-free. The deposits have a hardness of 600 ± 10 Vickers and, as such, are comparable to deposits from aqueous systems.

The usage of the green synthesis method to produce nanoparticles (NPs) has received great acceptance among the scientific community in recent years. This, perhaps, is owing to its eco-friendliness and the utilization of non-toxic materials during the synthesizing process. The green synthesis approach also supplies a reducing and a capping agent, which increases the stability of the NPs through the available phytochemicals in the plant extractions. The present study describes a green synthesis method to produce nano-silica (SiO ₂ ) NPs utilizing Rhus coriaria L. extract and sodium metasilicate (Na ₂ SiO ₃ .5H ₂ O) under reflux conditions. Sodium hydroxide (NaOH) is added to the mixture to control the pH of the solution. Then, the obtained NPs have been compared with the chemically synthesized SiO ₂ NPs. The structure, thermal, and morphological properties of the SiO ₂ NPs, both green synthesized and chemically synthesized, were characterized using Fourier-transform infrared spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM). Also, the elemental compassion distribution was studied by energy-dispersive X-ray spectroscopy (EDX). In addition, the zeta potential, dynamic light scatter (DLS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) was used to study the stability, thermal properties, and surface area of the SiO ₂ NPs. The overall results revealed that the green synthesis of SiO ₂ NPs outperforms chemically synthesized SiO ₂ NPs. This is expected since the green synthesis method provides higher stability, enhanced thermal properties, and a high surface area through the available phytochemicals in the Rhus coriaria L. extract.