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 Effect of fuel and solvent on soot oxidation activity of ceria nanoparticles synthesized by solution combustion method(KeAi Communications Co., 2019) Patil, S.S.; Prasad Dasari, H.P.Effect of fuel (glycine and urea) and solvent (water, acetone and ethanol) on the soot oxidation activity of ceria nanoparticles synthesized by solution combustion method is carried out in the present study. X-ray diffraction (XRD) patterns displayed a fluorite structure and the Tauc's plot obtained from UV-Diffusive Reflectance spectroscopy (UV-DRS) showed that the band gap value was around 2.9–3.1 eV for the synthesized ceria nanoparticles irrespective of the fuel and solvent used. Ceria nanoparticles synthesized using glycine and acetone resulted in lower crystallite size, higher facet ratios ([1 0 0]/[1 1 1] and [1 1 0]/[1 1 1]) and higher lattice strain than compared to other solvents and fuels and thus resulted in better soot oxidation activity (T50 = 416 °C). The present synthesis method has played a significant role in improving the reactive facet ratios, providing lower crystallite size and high lattice strain. © 2019Item 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 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 Engineers