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A simple, eco-friendly phytosynthesis of copper oxide nanoparticles (CuO NPs) using Cassia auriculata leaf extract was reported. The prepared CuO NPs was characterized by UV–vis spectroscopy which exhibited the surface plasmon resonance (SPR) band at 380–385 nm. TEM and EDX analysis confirmed that CuO NPs were spherical and in size range of 30–35 nm with identified elements Cu and O. X-ray diffraction (XRD) spectrum showed the crystalline nature of the prepared CuO NPs. FTIR spectrum confirmed the presence of Cu–O functional groups. CuO NPs showed significant antibacterial efficacy against all the tested bacterial strains, i.e., Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. CuO NPs showed strong antibacterial action against B. subtilis and E. coli than P. aeruginosa and S. aureus. The results of this study revealed that C. auriculata leaf extract was found to be an effective bio-reducing agent for CuO NPs synthesis and also the antibacterial efficacy of phytofabricated CuO may be useful for its applications in medical and textile industries.

High quality silver nanowires (AgNWs) were synthesized by using CoCl2 as a growth promoting additive in glycerol/water combination as a solvent. This method is not only time saving but also helpful to control morphology of AgNWs. A series of experiments were performed to optimize volume ratio of glycerol to water (G/W). The synergetic effect of the volume ratio of G/W and concentration of growth promoting additive on the morphology of AgNWs was investigated. The possible mechanism for the growth of AgNWs was elucidated by monitoring in situ generation of AgCl as a prominent event. Controlled experiments were performed to investigate the role of individual cobalt and chloride ions by using Co(NO3)2 and NaCl, respectively. The obtained AgNWs were characterized by SEM, TEM and XRD, while surface properties of the obtained AgNWs were studied by XPS. It was found that at specific volume ratio of G/W (3.5:1), mole ratio of PVP to AgNO3 (0.7:1) and concentration of CoCl2 (4 mM), high quality AgNWs were obtained.

Transparent nanocrystalline TiO2 thin films with high photocatalytic activity and photo-induced wettability were successfully deposited on a glass slide. Crystal phase transformations and particle size of TiO2 were investigated. Structural and morphological properties of the films were investigated. The photocatalytic activity of the TiO2 films was evaluated. It is found that the photocatalytic activity of TiO2 thin films is significantly decreased by increasing the annealing temperature, which results in a decrease in BET surface area and an increase in crystal size. In addition, increasing film thickness within a certain range significantly improves the photocatalytic activity without causing crack formation of the TiO2 films. Photocatalytic oxidation and photo-induced wettability conversion on the films were investigated. It is found that photo-induced hydrophilic conversion is observed even on the samples annealed at high temperature. The best photo-generated activities are obtained by optimization of dip-coating cycles and annealing temperatures.

Spectral convertors are promising materials for solar cells as they engineered the band gap necessary for suppressing the losses. Existing spectral convertors have small stokes shift which exerts re-absorption losses due to the overlap of spectrum and limits light catching ability. Here we present large stoke shift chromium doped rhombohedral Al2O3: Cr3+ as a spectral convertor from UV–VIS to red region as single doped with maximum coverage of solar spectrum in UV region. The large stoke shifts in red region around 694 nm originate from 2Eg to 4A2g and broad absorption originates from $$^{{\text{4}}}{{\text{A}}_{{\text{2g}}}}{ \to ^{\text{4}}}{{\text{T}}_{{\text{1g}}}},{{\text{ }}^{\text{4}}}{{\text{A}}_{{\text{2g}}}}{ \to ^{\text{4}}}{{\text{T}}_{{\text{2g}}}}$$ . This broad absorption (300–600 nm) and large stokes shift emission at 694 nm suggest that the Cr3+ dopant rhombohedral Al2O3 is well suited as spectral convertors for enhancing the efficiency of the solar cell through better matching of spectral response with spectral distribution of light striking on the solar cell.

Three new heteronuclear hexacyanometallate(III) coordination polymers (CPs), [Cd3(µ-3ampy)4(H2O)4Cr2(µ-CN)8(CN)4]n (1), [Cd3(µ-3ampy)2(H2O)2Fe2(µ-CN)5(CN)7]n (2) and [Cd3(µ-3ampy)4(H2O)4Co2(µ-CN)8(CN)4]n (3), were synthesized with 3-(aminomethyl)pyridine (3ampy) ligand. All CPs were characterized by FT-IR, Raman, elemental, thermal analysis as well as single crystal X-ray diffraction and powder X-ray diffraction techniques. The single crystal X-ray diffraction analyses shows that the CPs 1 and 3 are two-dimensional structures, whereas CP 2 is a three-dimensional structure where two adjacent metal ions ions are linked via 3ampy and CN bridges. The coordination spheres of all CPs show distorted octahedral geometries. CP 3 was mainly tested as heterogenous catalyst for peroxidative oxidation of benzyl alcohol and its derivatives (4-chloro, 4-bromo, 4-methyl, 4-metoxy and 4-nitro benzyl alcohol). From the results, the highest aldehyde formation was obtained from the oxidation of benzyl alcohol with overall yield as 100%. In addition, catalytic reactions exhibited high selectivity towards aldehyde and no over-oxidation product (carboxylic acid) was observed.

Application of biological organisms, such as microorganisms, plant extract or plant biomass, could be an alternative to chemical and physical methods of the synthesis of nanoparticles. Following this statement, the present work focused on conducting the synthesis of platinum nanoparticles using herbal Bidens tripartitus extract. The formed platinum nanoparticles were characterized by Ultraviolet–Visible, Fourier Transform-Infrared (FT-IR), scanning electron microscopy and EDS analyzer, transmission electron microscopy and atomic force microscopy (AFM) measurements. AFM analysis confirmed the presence of platinum nanoparticles with the size of 4 nm. In the FT-IR spectrum of B. tripartitus herbal extract, there were observed peaks characteristic of phenols. Also, herbal B. tripartitus extract is an effective medium for the synthesis of platinum nanoparticles.