Preparation and Characterization of Ce0.65Hf0.25M0.1O2- δ (M = rare earth elements) with high Oxygen Storage Capacity and their Application to Steam Reforming of Methane

Dasari, Harshini (2016) Preparation and Characterization of Ce0.65Hf0.25M0.1O2- δ (M = rare earth elements) with high Oxygen Storage Capacity and their Application to Steam Reforming of Methane. In: International Conference on recent trends in Engineering & Materials Science, 17/03/2016, Jaipur National University, Jaipur.

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Abstract

Owing to their high oxygen storage and transport capability, ceria (CeO2) based materials have attracted significant attention for a wide range of catalytic applications in three-way catalysis [1]. The oxygen storage capacity (OSC) is associated with the formation of oxygen vacancies along with their diffusion ability in ceria [2], which can further be enhanced by the incorporation of dopants into the ceria lattice [3]. Due to its smaller ionic radius than Ce4+, the doping of the nonreducible, isovalent Hafnium cation ion (Hf4+) into ceria can induce the distortion and expansion of the CeO2 lattice to facilitate the generation of oxygen vacancies [3]. In order to develop efficient materials possessing higher oxygen storage capacity (OSC) than ceria–hafnia (CH) based metal oxides, for a number of catalytic applications, Ce0.65Hf0.25M0.1O2- δ, (CH-M, M = Tb, Sm, Nd, Pr, and La), were prepared by the EDTA-citrate method. The structural and textural properties of the as synthesized materials were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analyses, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HRTEM). These analyses indicated that the doping of the rare earth elements could potentially induce enhanced OSC compared to the undoped CH solid solution. The increase in OSC is in the order of CH-Pr > CH-La > CH-Tb > CH-Nd > CH-Sm > CH. To elucidate the effect of these materials on Carbon suppression during reforming reactions, Ni/CH and Ni/CH-Pr catalysts were synthesized by a solvothermal method and their catalytic activities towards steam reforming of methane (SRM) with steam to carbon ratios of 1–2 at 700◦C were carried out. The Ni/CH-Pr catalyst exhibited superior activity and stability over Ni/CH for the SRM, which likely resulted from the enhanced oxygen mobility of the CH-Pr support.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: 1. J. Kaˇspar, P. Fornasiero, M. Graziani, Catal. Today 50 (1999) 285–298. 2. V.V. Kharton, A.A. Yaremchenko, E.N. Naumovich, F.M.B. Marques, J. Solid State Electrochem. 4 (2000) 243–266. 3. B.M. Reddy, G. Thrimurthulu, L. Katta, Y. Yamada, S.-E. Park, J. Phys. Chem. C 113 (2009) 15882–15890.
Subjects: Engineering > MIT Manipal > Chemical
Depositing User: MIT Library
Date Deposited: 12 Jan 2017 13:18
Last Modified: 12 Jan 2017 13:18
URI: http://eprints.manipal.edu/id/eprint/148041

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