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Summary The nanocomposite of NiO‐ZnO/graphene oxide (GO) was synthesized for applications in supercapacitor electrodes material. GO was produced using the modified Hummers' method, and the nanocomposite of NiO‐ZnO/GO was synthesized using the co‐precipitation method. Thin films of nanocomposite powder were deposited on quartzite (glass) and fluorine‐doped tin oxide substrates by a drop casting technique. X‐ray diffraction revealed the crystallographic information of NiO‐ZnO/GO nanocomposites. The surface morphology and elemental composition were studied using a scanning electron microscopy and energy‐dispersive X‐ray spectroscopy, respectively. The electrochemical properties were examined using cyclic voltammetry in a 1.0 M solution of Na2SO4 electrolyte with a three‐electrode system. Moreover, the NiO‐ZnO/GO binary metal oxides nanocomposite based electrodes fabricated for supercapacitor delivered a high specific capacitance of 1690 F g−1 for 1:1/GO sample at a scan rate of 10 mV s−1 and has excellent conductivity due to reduced band gap energy range of 1.52‐1.79 eV and with electrodes resistance of 0.02 Ω. The absence of semicircle in the Nyquist plot denotes low charge transfer resistance of the electrodes. The highest energy densities obtained for 1:1/GO and 2:1/GO are 192 and 148 Wh kg−1, respectively, while the highest power density obtained for 1:1/GO and 2:1/GO are 8.46 and 7.42 W kg−1, respectively. Our study paves way for a facile, affordable, nontoxic, and fast way to synthesis binary transition metal oxides/GO‐based electrodes material for high‐performance supercapacitor.

Zea mays L. dry husk extract was used to bio synthesize copper oxide nanoparticles. Red coloured cubic Cu 2 O nanoparticles were obtained for the first time via this simple, eco-friendly, green synthesis route. The Cu 2 O nanoparticles were thermally oxidized to pure monoclinic CuO nanoparticles at 600 °C. The phases of the copper oxides were confirmed from the x-ray diffraction (XRD) studies. The nanoparticle sizes as obtained from high resolution transmission electron microscope (HRTEM) analysis range from 10 to 26 nm, 36-73 nm and 30−90 nm for the unannealed Cu 2 O, 300 °C and 600 °C annealed CuO respectively. The values of the bandgap energies obtained from diffuse reflectance of the nanoparticles are 2.0, 1.30 and 1.42 eV respectively for the unannealed, 300 °C, and 600 °C annealed copper oxide nanoparticles. The 600 °C annealed copper oxide nanoparticles showed 91% and 90% degradation ability for methylene blue dye (BM) and textile effluent (TE) respectively under visible light irradiation. While CuO_300 is more effective to inhibit the growth of Escherichia coli 518,133 and Staphylococcus aureus 9144, Cu 2 O is better for Pseudomonas aeruginosa and Bacillus licheniformis. The results confirm the photo-catalytic and anti-microbial effectiveness of the copper oxide nanoparticles.

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