Faculty Publications
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Item Studies on the Solid Oxide Cell Perovskite Electrode Materials for Soot Oxidation Activity(Springer, 2019) Shenoy, C.S.; Patil, S.S.; Govardhan, P.; Shourya, A.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.Solid oxide cell (SOC) perovskite electrode materials (BSCF (Ba0.5Sr0.5Co0.8Fe0.2O3-?), LSCF (La0.6Sr0.4Co0.2Fe0.8O3-?) and LSCM (La0.75Sr0.25Cr0.5Mn0.5O3-?)) were synthesised using microwave-assisted reverse-strike co-precipitation method and tested for soot oxidation activity. The calcined perovskite materials were characterized using FT-IR, XRD, SEM and BSE, BET and BJH and XPS analysis. The mean activation energy for soot oxidation was calculated from Ozawa plots at various heating rates (5, 10, 15 and 20 K/min) at different levels of soot conversions (T10 to T90) for BSCF, LSCM and LSCF perovskite materials and was around 133 ± 11.5, 138 ± 9.9 and 152 ± 7.2 kJ/mol, respectively. Irrespective of the heating rates, BSCF material showed the lowest T50 temperature than compared to other samples, and it is correlated to the presence of Fe3O4 as a secondary phase. © 2019, Springer Nature Switzerland AG.Item Promotional effect of nickel addition on soot oxidation activity of Ce0.9Pr0.1O2 oxide catalysts(Springer, 2020) Rajvanshi, K.; Patil, S.S.; Lakhanlal, u.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.The present study investigates the promotional effect of Ni addition on soot oxidation activity of Ce0.9Pr0.1O2 oxide catalysts. A series of xNi-PDC (x= 0, 3, 5, 7, 10, 15, and 20 mol%) catalysts were synthesized by solution combustion synthesis method and characterized by XRD, Raman spectroscopy and TEM analysis. XRD and SAED patterns of the catalysts show cubic fluorite structure of ceria with an average crystallite size of 6–8 nm, and only 20Ni-PDC display NiO as a secondary phase. Raman spectra of xNi-PDC catalysts display an increase in oxygen vacancies. With a minimum addition of 10 mol% Ni to PDC, i.e., the 10Ni-PDC catalyst showed optimum soot oxidation activity (T50 = 360 °C) than compared to PDC and other Ni-PDC catalysts. Lattice strain and oxygen vacancies played a key descriptor role in showing better soot oxidation activity of the 10Ni-PDC catalyst. From the soot oxidation kinetic studies, the activation energy obtained by Ozawa plots for the 10Ni-PDC catalyst is 137 kJ/mol. © 2020, Institute of Chemistry, Slovak Academy of Sciences.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 Printex-U soot oxidation kinetic behaviour over Alumina and Quartz(Elsevier Ltd, 2022) Ganiger, S.; Patil, S.S.; Prasad Dasari, H.P.; Priyanka, R.; Kollimarla, S.Printex-U carbon (Pure Soot, S0) on alumina (SA) and quartz (SQ) powder were considered to understand the behaviour of oxidation reaction and kinetic analysis. A similar model of the single-step reaction was followed by the Soot (S0) and SA sample, while SQ followed a complex mechanism of multiple-step reactions. From the experimental and theoretical calculations, it was observed that there was a slight decrease in the T50 temperature for SA, which also had the lowest Ea, but there was an increase in T50 and Ea for SQ compared to the S0 sample. From the present study, it can be understood that the alumina enhanced the catalytic activity when compared to pure soot alone, whereas quartz inhibited the activity. The T50 temperature, Ea, and A calculated were obtained in SA < S0 < SQ. The soot properties and their kinetics will further help to design catalyzed diesel particulate filters. © 2021 Elsevier LtdItem A Negative Effect of Niobium-Doped Ceria on Soot Oxidation Activity‡(John Wiley and Sons Inc, 2022) Patil, S.S.; Naik, S.; Ramesh, M.D.; Harshini, H.; Prasad Dasari, H.P.Niobium-doped ceria catalysts were synthesized to study soot oxidation activity. X-Ray diffraction (XRD) and Raman analysis of the samples revealed the presence of a fluorite structure of CeO2 for all the doped samples. The T50 temperature of the pure CeO2 sample was more significant than that of bare soot. The high catalytic activity of the CeO2 catalyst can be attributed to the low crystallite size, high facet ratio, and the large Brunauer-Emmett-Teller (BET) surface area as compared to Nb-doped samples. The activation energy calculated by both Ozawa and KAS methods were found to be low for CeO2 when compared to Nb-doped samples. CeO2 resulted in better soot oxidation activity with low activation energy. © 2022 Wiley-VCH GmbHItem The catalytic effect of chromium-doped ceria-praseodymium on soot oxidation activity and its kinetics(Springer, 2024) Patil, S.S.; Prasad Dasari, H.P.Soot generated from the partial combustion of diesel significantly contributes to air pollution, and catalytic oxidation is currently an effective method for removing diesel soot particles. The chromium-doped ceria-praseodymium (Cr-CP) catalyst system is synthesized via solution combustion synthesis and evaluated for soot oxidation activity, with a subsequent kinetics study conducted. The XRD analysis of the catalysts indicated a decrease in crystallite size and increased lattice strain and reactive facet ratios for all Cr-doped CP samples. Raman analysis verified the existence of oxygen vacancy peaks in all chromium-doped CP catalysts. X-ray photoelectron spectroscopy (XPS) revealed the presence of adsorbed H2O or molecular water peaks in the O1s spectra for the 5 Cr-CP catalyst, which also exhibited a high concentration of surface Cr3+ ions. Thermogravimetric analysis (TGA) of soot oxidation indicated that 5 Cr-CP exhibited a superior T50 of 393 ± 2 °C, mostly attributed to the presence of reducible surface Cr3+ ion species. Kinetic analysis was performed on all Cr-doped CP catalysts to assess the kinetic triplets: activation energy, pre-exponential factor, and reaction model. The activation energy was low (87 kJ mol−1, Ozawa method) for 15 Cr-CP, while the pre-exponential factor was higher for 5 Cr-CP (7.39 × 1010 min−1). The Cr-CP catalyst system adhered to a power law, indicating a phase boundary-controlled reaction characterized by nucleation and growth mechanisms. The consistency between experimental and calculated curves confirmed that the developed catalysts adhered to the Avrami-Erofeev equation (Am) or the nucleation and growth model. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item An investigation on copper-loaded ceria-praseodymium catalysts for soot oxidation activity and its kinetics(Springer Science and Business Media Deutschland GmbH, 2024) Patil, S.S.; Prasad Dasari, H.P.The Cu-loaded Ce-Pr catalyst series was successfully developed to study their performance on soot oxidation activity and its kinetic behavior. The doped samples showed a similar trend for cubic fluorite structure except for CuO, which possessed a monoclinic structure from the XRD analysis. Facet ratios [{100}/{111} and {110}/{111}] for the reactive planes were calculated from XRD spectra; the ratio was high for the 5 Cu-CP catalysts. The oxygen vacancy peaks were noticed from Raman spectra for the doped samples. 5 Cu-CP displayed the better catalytic activity of T50 = 402 °C, which may be attributed to high reactive planes and better reducibility. The addition of Cu showed a slight enhancement in catalytic activity compared to CP and pure Ce. The kinetic triplets were evaluated: the activation energy (Ea), pre-exponential factor (A), and the reaction model. Pure Ce displayed the lowest Ea and A values, whereas pure Cu showed high Ea and A values by all the methods. Graphical abstract: (Figure presented.) © The Author(s) under exclusive licence to Associação Brasileira de Engenharia Química 2023.Item Ceria-Terbium-based electrospun nanofiber catalysts for soot oxidation activity and its kinetics(Taiwan Institute of Chemical Engineers, 2024) Patil, S.S.; Kumar, R.; Prasad Dasari, H.P.Background: Ceria-based materials have an excellent potential to be catalysts for catalytic three-way converters in the automobile industry. Developing Ceria-based nanofiber catalysts can be a significant approach for further exploring the application of these materials in automobile industries. Methods: In this study, Ag, Cu, or Co doped Ceria–Terbium nanofibers were synthesized using the electrospinning technique. The obtained nanofiber catalysts were characterized using FE-SEM, XRD, FT-Raman Spectroscopy, and BET-BJH analysis and tested for soot oxidation activity and its kinetics. Significant findings: FE-SEM examination reveals that the obtained nanofibers have a diameter ranging from around 100 to 600 nm. CeTbCo nanofibers exhibited a reduced particle size and enhanced pore formation. The XRD investigation revealed that all the nanofibers displayed a face-centered fluorite structure of CeO2. In Raman spectroscopy analysis, CeTbCo nanofibes showed the emergence of a secondary Co3O4 phase. The CeTbCo nanofiber catalyst showed better SBET (specific surface area) (66 m2/g) and average pore size (12.08 nm) and total pore volume (0.223 cc/g)), better soot oxidation activity (T50 = 347 ℃) than other nanofiber catalysts. The CeTbCo nanofiber catalyst exhibited an activation energy of 132 kJ mol−1 and a pre-exponential factor (ln (A)) of 25.63 min−1. © 2024 Taiwan Institute of Chemical EngineersItem Soot oxidation activity and kinetics of Ce0.9M0.1O2-δ (M = Cs, Mg, Ca) catalysts: Impact of Cs doping in ceria and impact of nanorods on catalytic activity(Institution of Chemical Engineers, 2024) Nayak, A.S.; Patil, S.S.; Prasad Dasari, H.P.; Telaginatot, D.; Rynjah, M.; Cheruku, S.Solution combustion method is used to synthesize Ce0.9M0.1O2-δ (M = Cs, Mg, Ca) catalysts and calcined at 600 °C/5 h. XRD and Raman Spectroscopy Analyses the chemical structure, the phases observed, and the oxygen defects in the synthesized catalysts. A cubic fluorite structure of CeO2 has been noticed for all the catalysts from XRD and Raman Spectroscopy analyses. FE-SEM micrographs are used to analyze the morphology of the Ce0.9M0.1O2-δ (M = Cs, Mg, Ca) catalysts. Ce0.9Cs0.1O2-δ catalyst shows the presence of nanorods (diameter: 63 nm), which are not seen in the other catalysts. The redox and surface properties of the synthesized catalysts are tested by H2-Temperature Programmed Reduction (H2-TPR) and O2-Temperature Programmed Desorption (O2-TPD), respectively. The Ce0.9Cs0.1O2-δ catalyst shows the greatest degree of reducibility from TPR studies and for the Ce0.9Cs0.1O2-δ catalyst, the oxygen species evolved from the O2-TPD studies are also the highest. Thermogravimetric Analysis (TGA) has been used to carry the soot oxidation activity of the developed catalysts. Soot oxidation kinetic studies have been conducted at different heating rates (5, 10, and 15 °C/min) for the catalysts. The kinetic triplets for the developed catalysts have been obtained, and rate plots ([Formula presented] vs. temperature) and Arrhenius plots (ln(k) vs. [Formula presented]) have been developed for the catalysts. From the soot oxidation and kinetic studies for the developed catalysts, Ce0.9Cs0.1O2-δ shows better soot oxidation activity (T50 = 372 °C) than the other two catalysts, while Ce0.9Mg0.1O2-δ (T50 = 556 °C) shows the lowest soot oxidation activity. All the catalysts follow a non-integral exponential model for soot oxidation, and the Ce0.9Cs0.1O2-δ catalyst has the lowest activation energy. © 2024 Institution of Chemical EngineersItem 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.