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Title: Particle size effect of redox reactions for Co species supported on silica

Abstract

Conversions of chemical states during redox reactions of two silica-supported Co catalysts, which were prepared by the impregnation method, were evaluated by using an in situ XAFS technique. The addition of citric acid into the precursor solution led to the formation on silica of more homogeneous and smaller Co particles, with an average diameter of 4 nm. The supported Co{sub 3}O{sub 4} species were reduced to metallic Co via the divalent CoO species during a temperature-programmed reduction process. The reduced Co species were quantitatively oxidized with a temperature-programmed oxidation process. The higher observed reduction temperature of the smaller CoO particles and the lower observed oxidation temperature of the smaller metallic Co particles were induced by the higher dispersion of the Co oxide species, which apparently led to a stronger interaction with supporting silica. The redox temperature between CoO and Co{sub 3}O{sub 4} was found to be independent of the particle size. - Graphical abstract: Chemical state conversions of SiO{sub 2}-supported Co species and the particle size effect have been analyzed by means of in situ XAFS technique. The small CoO particles have endurance against the reduction and exist in a wide temperature range. Display Omitted - Highlights: • The conversionsmore » of the chemical state of supported Co species during redox reaction are evaluated. • In operando XAFS technique were applied to measure redox properties of small Co particles. • A small particle size affects to the redox temperatures of cobalt catalysts.« less

Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
22584212
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 241; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; CATALYSTS; CHEMICAL STATE; CITRIC ACID; COBALT; COBALT OXIDES; FINE STRUCTURE; OXIDATION; PARTICLE SIZE; PARTICLES; REDOX REACTIONS; SILICA; SILICON OXIDES; SOLUTIONS; STRONG INTERACTIONS; TEMPERATURE RANGE; X-RAY SPECTROSCOPY

Citation Formats

Chotiwan, Siwaruk, Tomiga, Hiroki, Katagiri, Masaki, Yamamoto, Yusaku, Yamashita, Shohei, Katayama, Misaki, and Inada, Yasuhiro, E-mail: yinada@fc.ritsumei.ac.jp. Particle size effect of redox reactions for Co species supported on silica. United States: N. p., 2016. Web. doi:10.1016/J.JSSC.2016.06.020.
Chotiwan, Siwaruk, Tomiga, Hiroki, Katagiri, Masaki, Yamamoto, Yusaku, Yamashita, Shohei, Katayama, Misaki, & Inada, Yasuhiro, E-mail: yinada@fc.ritsumei.ac.jp. Particle size effect of redox reactions for Co species supported on silica. United States. doi:10.1016/J.JSSC.2016.06.020.
Chotiwan, Siwaruk, Tomiga, Hiroki, Katagiri, Masaki, Yamamoto, Yusaku, Yamashita, Shohei, Katayama, Misaki, and Inada, Yasuhiro, E-mail: yinada@fc.ritsumei.ac.jp. Thu . "Particle size effect of redox reactions for Co species supported on silica". United States. doi:10.1016/J.JSSC.2016.06.020.
@article{osti_22584212,
title = {Particle size effect of redox reactions for Co species supported on silica},
author = {Chotiwan, Siwaruk and Tomiga, Hiroki and Katagiri, Masaki and Yamamoto, Yusaku and Yamashita, Shohei and Katayama, Misaki and Inada, Yasuhiro, E-mail: yinada@fc.ritsumei.ac.jp},
abstractNote = {Conversions of chemical states during redox reactions of two silica-supported Co catalysts, which were prepared by the impregnation method, were evaluated by using an in situ XAFS technique. The addition of citric acid into the precursor solution led to the formation on silica of more homogeneous and smaller Co particles, with an average diameter of 4 nm. The supported Co{sub 3}O{sub 4} species were reduced to metallic Co via the divalent CoO species during a temperature-programmed reduction process. The reduced Co species were quantitatively oxidized with a temperature-programmed oxidation process. The higher observed reduction temperature of the smaller CoO particles and the lower observed oxidation temperature of the smaller metallic Co particles were induced by the higher dispersion of the Co oxide species, which apparently led to a stronger interaction with supporting silica. The redox temperature between CoO and Co{sub 3}O{sub 4} was found to be independent of the particle size. - Graphical abstract: Chemical state conversions of SiO{sub 2}-supported Co species and the particle size effect have been analyzed by means of in situ XAFS technique. The small CoO particles have endurance against the reduction and exist in a wide temperature range. Display Omitted - Highlights: • The conversions of the chemical state of supported Co species during redox reaction are evaluated. • In operando XAFS technique were applied to measure redox properties of small Co particles. • A small particle size affects to the redox temperatures of cobalt catalysts.},
doi = {10.1016/J.JSSC.2016.06.020},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 241,
place = {United States},
year = {Thu Sep 15 00:00:00 EDT 2016},
month = {Thu Sep 15 00:00:00 EDT 2016}
}