Investigating the properties of GO/(Zn_xNi_1−x)O composites prepared by Sol–gel route for photocatalytic and gas sensing applications

This research studies the effects of volume ratios on the properties of GO/(Zn_xNi_1−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/ZnO_0.2NiO_0.8, GO/ZnO_0.5NiO_0.5, and GO/ZnO_0.8NiO_0.2 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.