High-quality nanostructure of dysprosium substituted nickel–cobalt ferrite and their composite with reduced graphene oxide (rGO) were synthesized. The structuraland photocatalytic properties of prepared samples were studied. The XRD and FTIR analysis confirmed the FCC spinel structure. The calculated average crystallite size of nanoparticles was around 7.8 nm. The bandgap energy of synthesized composition was found to be 2.27 eV. The uniform dispersion of nanoparticles on the graphene nanosheets were confirmed by the FESEM analysis. The photocatalytic efficiency of nanoparticles and their composites with rGO was studied for degradation of methylene blue (MB) under visible light irradiation. It was found that nanocomposite exhibited high photocatalytic activity (72.7%) as compared to Dy⁺³ substituted Ni-Co ferrite nanoparticles (52.4%). This enhanced photocatalytic activity can be attributed to the presence of graphene, which enhances the stability of nanocomposite and reduces the recombination of charge carriers.

In this paper, wet-chemically synthesized hierarchical NiO microspheres and their exfoliated (ExC)-based nanocomposites (NiO/ExC) as electrodes for supercapacitor applications have been reported. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopic (SEM) techniques were used to characterize the as-synthesized products. The study of PXRD revealed that NiO exhibits a cubic phase. Morphological analysis showed a hierarchical micro-spherical structure of mesoporous NiO particles. The as-synthesized hierarchically porous NiO manifested a specific capacitance of 331 F/g with 50% capacitance retention. But, exfoliated carbon (ExC)-based nanocomposite (0.07 g NiO/0.003 g ExC) showed a particular capacitance of 815 F/g at the scan rate of 5 mV/s, with 79% retention in capacitance. High electrical conductivity and larger surface area arising from synergistic effects between NiO and exfoliated carbon resulted in a tremendous electrochemical response of NiO/ExC nanocomposites. The inclusion of the ExC further improves electrical impedance spectroscopic results by facilitating the charge transfer. GRAPHICAL ABSTRACT

Titanium dioxide nanoparticles (TiO2(Aq) and TiO2(Et)) were synthesized by treating titanium tetraisopropoxide (TTIP) with the aqueous/ethanolic extracts of Morus nigra leaves. The synthetic method is an environmentally friendly, inexpensive and beneficial as the plant leaves act as stabilizing and reducing agents. The obtained NPs were characterized by FTIR spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and Raman spectroscopy. The crystallite sizes of TiO2(Aq) and TiO2(Et) NPs were found to be 0.17 and 0.076 nm, respectively. FTIR spectroscopy have shown the coating of plant material upon the surface of nanoparticles. SEM analysis has shown the round shape and irregular surface morphologies of nanoparticles. The bio-synthesized TiO2 NPs displayed negligible toxic hemolytic effects and had a little inhibition of Staphylococcus aureus and Proteus Mirabilis bacteria as compared to ciprofloxacin.