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An effective low-cost nano NiO-In2O3 electrode material for oxygen evolution (OER) is presented. Electrochemical studies uncovered electrocatalytic recital in Ascorbic Acid, Hydrogen Peroxide (H2O2), and ethanol. The cubic crystal structure of NiO-In2O3 was revealed by XRD. FT-IR, FE-SEM and HR-TEM studies exploit the structure and morphology of NiO-In2O3. Electrochemistry of NiO-In2O3 uncovered high current density (900mA/cm²) at substantially low overpotential (230mV), realizing its OER recital. On top, high mass activity and turnover frequency by NiO-In2O3 comprehend improved electrical and semiconductive properties in H2O2. The NiO-In2O3 durability beyond 90 hours was estimated by chronopotentiometry (CP). The Impedance analysis (EIS) revealed low charge transfer resistance and high exchange current density. Given electrocatalytic studies, we found a direct relationship between NiO-In2O3 nanocomposite and the degradation of H2O2 compared to its counterparts. Hence, this strategy can be an alternative and potential source of hydrogen and oxygen production at commercial scale. [ABSTRACT FROM AUTHOR]

The efficient degradation of organic effluent is always desirable when using advanced photocatalysts with enhanced activity under visible light. Nickel-doped indium oxide (Ni-In2O3) is synthesized via a hydrothermal route as well as its composites with reduced graphene oxide (rGO). Facile synthesis and composite formation methods lead to a well-defined morphology of fabricated nanocomposite at low temperatures. The bandgap energy of indium oxide lies in the range of 3.00–4.30 eV. Its high light absorption capacity, high stability, and non-toxicity make it a choice as a photocatalyst that is active under visible light. The transition metal Ni-doping changes the indium oxide's chemical, optical, and physicochemical properties. The Ni-In2O3 and rGO composites improved the charge transport and reduced the charge recombination. The phase analysis of the developed photocatalysts was performed using X-ray diffraction (XRD), and the morphological and structural properties were observed using advanced microscopic techniques (SEM and TEM), while UV-vis and FTIR spectroscopic techniques were used to confirm the structure and optical and chemical properties. The electrochemical properties of the photocatalysts were investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS), and the charge-transfer properties of the obtained photocatalysts and the mechanism of the photocatalytic degradation mechanism of methylene blue, a common dye used in the dyeing industry, were determined. [ABSTRACT FROM AUTHOR]

Heterogeneous Ni0.5Cu0.5−xZnxFe2O4 (0.0 ≤ x ≤ 0.5) nanoparticles are prepared via a green, solventless and additive-free, soft mechanochemical process at room temperature. This solid-state synthetic procedure yields ternary and quaternary oxide nanoparticles with uniform morphology (average particle size: 104–136 nm). X-ray diffraction analyses of Ni0.5Cu0.5−xZnxFe2O4 nanoparticles reveal a cubic spinel structure with crystallite size in the range of 24–31 nm. The lattice parameter (a) and hopping length for tetrahedral (LA) and octahedral (LB) lattice sites are found to increase with the increase in Zn2+ content, while X-ray (ρxrd) and bulk (ρbulk) densities decrease slightly due to increasing lattice volume. Ni0.5Cu0.5−xZnxFe2O4 nanoparticles with (x = 0.2, 0.3, 0.4) exhibit excellent dielectric performance with high permittivity (ε̍ = 92–111) and suppressed dielectric loss (ε̎ = 1.8–2.8) at high frequency (~ 106 Hz). The polarization mechanism is discussed, involving major contributions from the electron hopping (Fe2+ ↔ Fe3+) at the octahedral sites. The influence of Cu2+ and Zn2+ concentration on the cationic distribution and dielectric performance is analyzed. The electrical conductivity is found to follow the power law (σac = Aωn) with n = 0.7, which confirms the ac conduction phenomenon driven by the electron hopping mechanism. The dielectric behavior of Ni0.5Cu0.5−xZnxFe2O4 nanoparticles reveals their potential for applications in high-frequency microwave devices. [ABSTRACT FROM AUTHOR]