Patil, S.S.Prasad Dasari, H.P.Gouramma, P.Harshini, H.2026-02-032024Kinetics and Catalysis, 2024, 65, 6, pp. 775-787231584https://doi.org/10.1134/S0023158424601761https://idr.nitk.ac.in/handle/123456789/20759Abstract: Nickel oxide (NiO) nanoparticles were synthesized using four different methods: microwave co-precipitation (MCP), solution combustion synthesis (SCS), direct nitrate calcination (DNC), and the sol-gel process (SGP), incorporating organic additives such as glucose and fructose. X-ray diffraction and Raman spectroscopy analyses revealed that the NiO nanoparticles formed a face-centered cubic phase characterized by Ni–O bond stretching. The SCS method produced NiO nanoparticles with higher lattice strain, smaller crystallite size, and an increased facet ratio ({110}) compared to the other methods. Transmission electron microscopy indicated that the order of nano-agglomeration size for the NiO nanoparticles was DNC > MCP > SGP > SCS. The NiO nanoparticles synthesized via SCS, SGP and MCP exhibited irregular hexagonal shapes. Among the synthesized nanoparticles, those produced by the SCS method demonstrated the highest catalytic activity (T<inf>50</inf> = 478°C), followed by DNC (T<inf>50</inf> = 492°C), MCP (T<inf>50</inf> = 495°C), and SGP (T<inf>50</inf> = 538°C). A kinetic study was conducted to evaluate key parameters, including activation energy, preexponential factor, and reaction model. The experimental curves of soot conversion were compared with theoretical curves derived from the evaluated kinetic parameters. The NiO nanoparticles synthesized via SCS exhibited the highest kinetic activity with the enhanced reaction rate at lower temperatures. © Pleiades Publishing, Ltd. 2024.Activation energyCatalytic oxidationCombustion synthesisCoprecipitationDustHigh resolution transmission electron microscopyNanoclayNanoparticlesPhotoionizationReaction ratesSol-gelsX ray diffraction analysisCatalytic soot oxidation activityCo-precipitationFacet ratioLattice strainNickel oxide nanoparticleOxidation activitiesSolution combustion synthesisSoot oxidationSynthesis methodSynthesisedSol-gel process