Department of Chemical Engineering

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Author: search.filters.author.Roy, BanasriSubject: search.filters.subject.Reforming

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    Reforming of model biogas using Ni/CeO2/γ-Al2O3 monolith catalyst
    (Elsevier, 2023) Roy, Banasri; Srinivas, Appari
    This study aims to develop a Ni-Ce coated alumina cordierite monolith for reforming model biogas. Dry reforming of biogas (DRBG) experiments are carried out at 800 °C for various ratios of CH4/CO2, mainly 1.0, 1.5, and 2.0. A 2 × 2 cm monolith is wash-coated with alumina and loaded with Ni-Ce by the wet impregnation method. For improving metal support interactions, the monoliths are calcined at 800 °C for 20 h and reduced in the presence of H2. The catalysts exhibited a CH4 conversion of 91%, 60%, and 48% and CO2 conversions of 60%, 80%, and 81% for a feed ratio of 1.0, 1.5, and 2.0, respectively. The prepared catalysts are characterized by employing various techniques such as XRD and FESEM incombined with EDS and Raman analysis. XRD of calcined catalysts displayed the phases of CeO2, Al2O3, NiO, NiAl2O4, and the monolith peaks and catalysts showed a stable activity for 40 h time-on stream for all the ratios. The Raman and FESEM analysis of spent catalysts reveal the presence of carbon deposition. However, catalysts showed high activity due to active Ni particles present on the top of the carbon nanotubes.
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    Study of preparation method and oxidization/reduction effect on the performance of nickel-cerium oxide catalysts for aqueous-phase reforming of ethanol
    (Elsevier, 2015-12) Roy, Banasri
    The effect of preparation method and oxidation state of the active metal on the catalytic activity of Ni–Ce–O catalysts was studied for aqueous phase reforming of ethanol. A sol-gel (SG) route and a solution combustion synthesis (SCS) method were used for the preparation of 10 wt% Ni loaded catalysts. The catalytic activity of three groups of catalysts; reduced at 425 °C (HR, metallic Ni), reduced at 1000 °C (FR, metallic Ni), and not reduced (NR, as NiO) were tested at different operating conditions. The difference in the metal particle sizes, governed by the preparation method, affects the catalytic efficiency most, not the reduced or oxidized state of Ni. The SG samples were superior for ethanol conversion and selectivity for H2 and CO2 compared to the SCS samples. The X-ray photoelectron spectroscopy (XPS) analysis of the samples demonstrated that the relative ratio of Ce2O3 to CeO2 increased inside the reactor. While Ni doping increases oxygen mobility in the Ce–O lattice, Ce3+ converts Ni2+ to metallic Ni inside the reactor. This can explain why the reduction stage for Ni–Ce–O system in APR is irrelevant. Higher oxygen mobility through the support helps oxidation of CO to CO2 leading to improved catalytic performance.