Title: Synthesis of murdochite-type Ni{sub 6}MnO{sub 8} with variable specific surface areas and the application in methane oxidation

Abstract

To synthesize a murdochite-type Ni{sub 6}MnO{sub 8} with variable specific surface areas, an oxalate precursor was calcined at 350–500 °C in flowing argon, and the calcined sample was heated to 600 °C in air. The lattice constant of the Ni{sub 6}MnO{sub 8} did not depend on the calcination temperature of the precursor, while the specific surface area decreased from 8.4 m{sup 2}/g to 2.6 m{sup 2}/g when increasing the calcination temperature of the precursor. The methane (CH{sub 4}) oxidation data indicated that the temperature corresponding to the 50% conversion (T{sub 50%}) of Ni{sub 6}MnO{sub 8} calcined at 350 °C or 400 °C was lower than that of all other Ni{sub 6}MnO{sub 8} specimens. However, the intrinsic conversion of Ni{sub 6}MnO{sub 8} calcined at 350 °C, which is defined as conversion per specific surface area, was half of that of all other Ni{sub 6}MnO{sub 8} specimens. The degree of crystallinity and catalytic performance of the Ni{sub 6}MnO{sub 8} calcined at 400 °C were high. - Graphical abstract: The conversion of CH{sub 4} into CO{sub 2} and H{sub 2}O on Ni{sub 6}MnO{sub 8}, which was heated at 600 °C in air after the calcination of the precursor at 350 °C, 400 °C,more » 450 °C, or 500 °C in flowing argon, was measured. Since the specific surface area was strongly affected by the calcination temperature of the precursor, intrinsic conversion (IC) was defined as conversion per the specific surface area. For comparison, the IC value on Ni{sub 6}MnO{sub 8} synthesized by the direct calcination of the precursor at 600 °C in air is plotted. - Highlights: • The oxalate precursor was calcined at 350–500 °C in flowing argon. • Murdochite-type Ni{sub 6}MnO{sub 8} was obtained by heating the calcined sample in air. • The specific surface area of Ni{sub 6}MnO{sub 8} varied with the calcination temperature. • The degree of crystallinity and catalysis of Ni{sub 6}MnO{sub 8} calcined at 400 °C were high.« less

Authors:

Taguchi, Hideki ^[1]; Tahara, Shohei ^[1]; Okumura, Mikoto; Hirota, Ken ^[2]

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+ Show Author Affiliations

1. The Graduate School of Natural Science and Technology (Science), Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama 700-8530 (Japan)
2. Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Kyo-Tanabe 610-0321 (Japan)

Publication Date:

Tue Jul 01 00:00:00 EDT 2014

OSTI Identifier:

22334297

Resource Type:

Journal Article

Journal Name:

Journal of Solid State Chemistry

Additional Journal Information:

Journal Volume: 215; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CALCINATION; CARBON DIOXIDE; CATALYSIS; CRYSTAL STRUCTURE; LATTICE PARAMETERS; METHANE; OXIDATION; SYNTHESIS; WATER