Synthesis of CuO@NiO/rGO nanocomposite with enhanced electrochemical and photocatalytic properties in energy and environmental applications

In this study, pristine rGO and CuO@NiO/rGO (CNR) nanocomposites (NCs) with different rGO ratios (10%, 25% and 50%) into CuO@NiO has been formed as well as explored to XRD, SEM with EDX, TEM, XPS, UV-visible techniques. TEM analysis revealed ultra-thin nanosheets of rGO with lengths of several tens of micrometer and CuO@NiO particle sizes is - 25 nm. The CNR-(50:50) NCs Cu2p, Ni2p, O1s and C1s chemical states were confirmed via XPS analysis. The energy gap (Eg) of pure rGO is 3.99 eV whereas the CNR- 90:10, 75:25 and 50:50 NCs energy gap (Eg) values are viz., 1.43 eV, 1.41 eV and 1.39 eV. The CNR-(50:50) sample exhibits higher photocatalytic crystal violet (CV) degradation (99%) with rate constant kobs = 6.67 +/- 0.0042 x 10-2 min-1. The cyclic voltammetry (CV) result shows maximum specific capacitance values was found to be 302 Fg-1 at 10 mV/s for CNR-(50:50) electrode. The EIS result shows conductivity value was found to be in the range between 1.468 S/m to 2.982 S/m for the prepared all electrodes. Furthermore, dielectric constant (epsilon '), dielectric loss (epsilon"), dissipation factor (tan delta) real and imaginary part of electric modulus (M ' and M '') are investigated and the results is applicable to supercapacitor devices for CNR NCs electrode.