Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction

Yosuke Nakaji; Daisuke Kobayashi; Yoshinao Nakagawa; Masazumi Tamura; Kazu Okumura; Keiichi Tomishige

doi:10.1021/acs.jpcc.9b00515

Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction

Yosuke Nakaji, Daisuke Kobayashi, Yoshinao Nakagawa, Masazumi Tamura, Kazu Okumura, Keiichi Tomishige

ENG - Applied Chemistry

Research output: Contribution to journal › Article › peer-review

3 Citations (Scopus)

Abstract

The structural change of Ru/CeO₂ and Ru/SiO₂ catalysts during pretreatments was investigated by in situ Ru K edge quick-scanning X-ray absorption fine structure (XAFS) combined with temperature-programmed reduction with H₂ and X-ray diffraction (XRD). After impregnation and drying, two pretreatment sequences were applied: (i) calcination in air at 573 K and reduction with H₂ and (ii) heating in inert gas at 573 K and reduction with H₂. In sequence (i) of Ru/CeO₂, the extended XAFS (EXAFS) spectra showed the formation of crystalline RuO₂ during calcination. On the other hand, in sequence (ii) of Ru/CeO₂ and Ru/SiO₂, the EXAFS results indicated that the Ru oxide was still noncrystalline after heating. The size of Ru metal particle during reduction was determined by Ru-Ru coordination number in EXAFS (CN_Ru-Ru) and reduction degree. The size was almost constant for Ru/CeO₂ (CN_Ru-Ru: about 4) or Ru/SiO₂ (CN_Ru-Ru: about 8) in sequence (ii), indicating the absence of aggregation. The size was increased for Ru/CeO₂ in sequence (i); however, the XRD results suggested that each RuO₂ crystallite was slowly reduced to one Ru particle. After all, aggregation during reduction was not significant for all Ru/CeO₂ and Ru/SiO₂ catalysts.

Original language	English
Pages (from-to)	20817-20828
Number of pages	12
Journal	Journal of Physical Chemistry C
Volume	123
Issue number	34
DOIs	https://doi.org/10.1021/acs.jpcc.9b00515
Publication status	Published - 2019 Jan 17

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Energy(all)
Physical and Theoretical Chemistry
Surfaces, Coatings and Films

Access to Document

10.1021/acs.jpcc.9b00515

Fingerprint Dive into the research topics of 'Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction'. Together they form a unique fingerprint.

Cite this

Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction. / Nakaji, Yosuke; Kobayashi, Daisuke; Nakagawa, Yoshinao; Tamura, Masazumi; Okumura, Kazu; Tomishige, Keiichi.

In: Journal of Physical Chemistry C, Vol. 123, No. 34, 17.01.2019, p. 20817-20828.

Research output: Contribution to journal › Article › peer-review

@article{db7ce89d58ba4db2b24503a19528554b,

title = "Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction",

abstract = "The structural change of Ru/CeO2 and Ru/SiO2 catalysts during pretreatments was investigated by in situ Ru K edge quick-scanning X-ray absorption fine structure (XAFS) combined with temperature-programmed reduction with H2 and X-ray diffraction (XRD). After impregnation and drying, two pretreatment sequences were applied: (i) calcination in air at 573 K and reduction with H2 and (ii) heating in inert gas at 573 K and reduction with H2. In sequence (i) of Ru/CeO2, the extended XAFS (EXAFS) spectra showed the formation of crystalline RuO2 during calcination. On the other hand, in sequence (ii) of Ru/CeO2 and Ru/SiO2, the EXAFS results indicated that the Ru oxide was still noncrystalline after heating. The size of Ru metal particle during reduction was determined by Ru-Ru coordination number in EXAFS (CNRu-Ru) and reduction degree. The size was almost constant for Ru/CeO2 (CNRu-Ru: about 4) or Ru/SiO2 (CNRu-Ru: about 8) in sequence (ii), indicating the absence of aggregation. The size was increased for Ru/CeO2 in sequence (i); however, the XRD results suggested that each RuO2 crystallite was slowly reduced to one Ru particle. After all, aggregation during reduction was not significant for all Ru/CeO2 and Ru/SiO2 catalysts.",

author = "Yosuke Nakaji and Daisuke Kobayashi and Yoshinao Nakagawa and Masazumi Tamura and Kazu Okumura and Keiichi Tomishige",

year = "2019",

month = jan,

day = "17",

doi = "10.1021/acs.jpcc.9b00515",

language = "English",

volume = "123",

pages = "20817--20828",

journal = "Journal of Physical Chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

number = "34",

}

TY - JOUR

T1 - Mechanism of Formation of Highly Dispersed Metallic Ruthenium Particles on Ceria Support by Heating and Reduction

AU - Nakaji, Yosuke

AU - Kobayashi, Daisuke

AU - Nakagawa, Yoshinao

AU - Tamura, Masazumi

AU - Okumura, Kazu

AU - Tomishige, Keiichi

PY - 2019/1/17

Y1 - 2019/1/17

N2 - The structural change of Ru/CeO2 and Ru/SiO2 catalysts during pretreatments was investigated by in situ Ru K edge quick-scanning X-ray absorption fine structure (XAFS) combined with temperature-programmed reduction with H2 and X-ray diffraction (XRD). After impregnation and drying, two pretreatment sequences were applied: (i) calcination in air at 573 K and reduction with H2 and (ii) heating in inert gas at 573 K and reduction with H2. In sequence (i) of Ru/CeO2, the extended XAFS (EXAFS) spectra showed the formation of crystalline RuO2 during calcination. On the other hand, in sequence (ii) of Ru/CeO2 and Ru/SiO2, the EXAFS results indicated that the Ru oxide was still noncrystalline after heating. The size of Ru metal particle during reduction was determined by Ru-Ru coordination number in EXAFS (CNRu-Ru) and reduction degree. The size was almost constant for Ru/CeO2 (CNRu-Ru: about 4) or Ru/SiO2 (CNRu-Ru: about 8) in sequence (ii), indicating the absence of aggregation. The size was increased for Ru/CeO2 in sequence (i); however, the XRD results suggested that each RuO2 crystallite was slowly reduced to one Ru particle. After all, aggregation during reduction was not significant for all Ru/CeO2 and Ru/SiO2 catalysts.

AB - The structural change of Ru/CeO2 and Ru/SiO2 catalysts during pretreatments was investigated by in situ Ru K edge quick-scanning X-ray absorption fine structure (XAFS) combined with temperature-programmed reduction with H2 and X-ray diffraction (XRD). After impregnation and drying, two pretreatment sequences were applied: (i) calcination in air at 573 K and reduction with H2 and (ii) heating in inert gas at 573 K and reduction with H2. In sequence (i) of Ru/CeO2, the extended XAFS (EXAFS) spectra showed the formation of crystalline RuO2 during calcination. On the other hand, in sequence (ii) of Ru/CeO2 and Ru/SiO2, the EXAFS results indicated that the Ru oxide was still noncrystalline after heating. The size of Ru metal particle during reduction was determined by Ru-Ru coordination number in EXAFS (CNRu-Ru) and reduction degree. The size was almost constant for Ru/CeO2 (CNRu-Ru: about 4) or Ru/SiO2 (CNRu-Ru: about 8) in sequence (ii), indicating the absence of aggregation. The size was increased for Ru/CeO2 in sequence (i); however, the XRD results suggested that each RuO2 crystallite was slowly reduced to one Ru particle. After all, aggregation during reduction was not significant for all Ru/CeO2 and Ru/SiO2 catalysts.

UR - http://www.scopus.com/inward/record.url?scp=85070882411&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85070882411&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.9b00515

DO - 10.1021/acs.jpcc.9b00515

M3 - Article

AN - SCOPUS:85070882411

VL - 123

SP - 20817

EP - 20828

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 34

ER -