Faculty Publications
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Item Effect of morphology and oxidation state of nickel on diesel soot oxidation activity(Elsevier Ltd, 2022) Vijay, M.P.A.; Patil, S.S.; Madhura, D.R.; Anjana, A.P.; Gouramma, P.; Prasad Dasari, H.P.; Arya, S.B.; Harshini, H.NiO sample is synthesized using the EDTA citrate complex method and calcined at 600 °C/5 h. Ni sample was acquired by reducing NiO to Ni at 600 °C in 4% H2/N2 atmosphere. Its physicochemical properties were obtained by XRD and Raman spectroscopy analysis, where it confirmed the complete reduction of NiO to Ni. SEM and TEM micrographs revealed a drastic particle growth for the Ni, indicating NiO sintering during the reduction process and a considerable surface morphology change. Ozawa and KAS methods were used to calculate the mean activation energy (Ea) value. NiO displayed lower Ea than Ni. Hence, NiO showed better catalytic activity than Ni. © 2022Item Soot Oxidation Kinetics on Nickel Oxide: Effects of Various Synthesis Techniques(Pleiades Publishing, 2024) Patil, S.S.; Prasad Dasari, H.P.; Gouramma, P.; Harshini, H.Abstract: 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 (T50 = 478°C), followed by DNC (T50 = 492°C), MCP (T50 = 495°C), and SGP (T50 = 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.