Monoatomically dispersed Pd/TiO 2 catalyst effective for epoxidation of propylene at ambient temperature in the presence of H 2 and O 2

Susumu Hikazudani, Tatsuya Mochida, Naofumi Matsuo, Katsutoshi Nagaoka, Tatsumi Ishihara, Hisayoshi Kobayashi, Yusaku Takita

Research output: Contribution to journalArticle

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Abstract

The catalytic activity of monoatomically dispersed Pd supported on TiO 2 toward propylene epoxidation in the presence of H 2 and O 2 was studied at ambient temperature, and both propylene oxide (PO) and propane were obtained. Short-chain alkanes also reacted but epoxide formation was not observed in those reactions except in the case of isobutane, which formed isobutylene oxide at a low rate. The optimum surface concentration of Pd on TiO 2 was 0.005-0.01 atom/nm 2; because the supported amount of Pd is extremely small relative to the surface area of the support, the supported Pd is thought to be monoatomically dispersed. Pd/TiO 2 catalysts prepared from a tetraphenylporphyrin-Pd chloride complex showed almost the same product distribution for propylene epoxidation as did catalysts prepared from Pd(NO 3) 2. Isotope exchange between H 2 and D 2 proceeded over Pd/TiO 2 with a low surface concentration (0.0001 atom-Pd/nm 2), and chemical potential calculations suggested that H 2 molecules could dissociatively adsorb onto the monoatomically dispersed Pd/TiO 2. A PO formation mechanism over the catalyst is proposed on the basis of these results. The results presented here may provide the first clear evidence of catalysis by monoatomically dispersed noble metals.

Original languageEnglish
Pages (from-to)89-98
Number of pages10
JournalJournal of Molecular Catalysis A: Chemical
Volume358
DOIs
Publication statusPublished - Jun 1 2012

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epoxidation
Epoxidation
propylene
ambient temperature
Propylene
propylene oxide
catalysts
Catalysts
Butanes
Oxides
atom concentration
Atoms
Propane
Alkanes
epoxy compounds
Chemical potential
Epoxy Compounds
butenes
butanes
Precious metals

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Physical and Theoretical Chemistry
  • Process Chemistry and Technology

Cite this

Monoatomically dispersed Pd/TiO 2 catalyst effective for epoxidation of propylene at ambient temperature in the presence of H 2 and O 2 . / Hikazudani, Susumu; Mochida, Tatsuya; Matsuo, Naofumi; Nagaoka, Katsutoshi; Ishihara, Tatsumi; Kobayashi, Hisayoshi; Takita, Yusaku.

In: Journal of Molecular Catalysis A: Chemical, Vol. 358, 01.06.2012, p. 89-98.

Research output: Contribution to journalArticle

Hikazudani, Susumu ; Mochida, Tatsuya ; Matsuo, Naofumi ; Nagaoka, Katsutoshi ; Ishihara, Tatsumi ; Kobayashi, Hisayoshi ; Takita, Yusaku. / Monoatomically dispersed Pd/TiO 2 catalyst effective for epoxidation of propylene at ambient temperature in the presence of H 2 and O 2 In: Journal of Molecular Catalysis A: Chemical. 2012 ; Vol. 358. pp. 89-98.
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