Search

This research studies the effects of volume ratios on the properties of GO/(ZnxNi1−x)O ternary composite prepared by a sol–gel technique. The ratios were produced by keeping the volume of graphene oxide (GO) constant whilst varying the volumes of zinc oxide, ZnO and nickel oxide, NiO to produce GO/ZnO0.2NiO0.8, GO/ZnO0.5NiO0.5, and GO/ZnO0.8NiO0.2 nanocomposites. The structural, morphological, elemental, optical, gas sensing, and photocatalytic properties of the synthesized nanocomposites have been investigated. EDX results confirmed the presence of graphene oxide, nickel oxide, and zinc oxide in the composites. The bandgap energy values exhibited a reduction as compared to the constituent compounds which range from 3.1 to 3.4 eV. Functional groups belonging to carbon, oxygen, nickel, zinc were obtained. The conductivity and activation energy of the ternary composites was also determined. The gas sensing properties were tested for NH3, H2S, and Cl2 at 100 ppm and 10 V; with the highest sensitivity recorded for H2S. The synthesized ternary composites were highly effective in degradation of dye with the efficiencies of 87.3%, 86.7%, and 88.0% respectively, obtained at 0.022 per minute, 0.020 per minute, 0.024 per minute for pseudo-first order rate constant. Results from the characterization show potential application of the composites in gas sensing and photocatalytic devices. [ABSTRACT FROM AUTHOR]

Inorganic photocatalytic materials exhibiting a highly efficient response to ultraviolet-visible light spectrum have become a subject of widespread global interest. Nanocomposite metal oxides, particularly Nickel Oxide (NiO) and Zinc Oxide (ZnO), have gained attention for their diverse applications in gas sensing and photocatalytic processes. In this work, ZnO-NiO (ZnO0.6NiO0.4 and ZnO0.4NiO0.6) binary nanocomposites were synthesized by hydrothermal technique. The binary nanocomposites were analyzed by UV-Visible spectrophotometer, X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared spectrophotometer (FTIR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The XRD pattern revealed that the nanocomposites, the peaks of both ZnO and NiO are present indicating the presence of both crystal structures hexagonal wurtzite and cubic. The miller indices, crystallite size, microstrain and dislocation density were determined from the XRD plot. FESEM and TEM analyses showed the spherical morphology of the synthesized composites with an approximate size of 10nm. The detailed analysis of ZnO–NiO binary nanocomposite sensor characteristics in terms of sensitivity, selectivity, response and recovery time were carried out and the nanocomposites were found to be highly sensitive to CO2 100 ppm at 350∘C and Cl2 at 200∘C. The photocatalytic degradation outcome showed 52% degradation of methylene blue at 10 ppm and 90w/m2. These results suggest the potential utility of these binary nanocomposites in photocatalytic applications for the degradation of organic pollutants. [ABSTRACT FROM AUTHOR]