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Title: Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties

Abstract

Monodisperse palladium particles of six distinct and controlled sizes between 4-16 nm were synthesized in a one-pot polyol process by varying the molar ratios of the two palladium precursors used, which contained palladium in different oxidation states. This difference permitted size control by regulation of the nucleation rate because low oxidation state metals ions nucleate quickly relative to high oxidation state ions. After immobilization of the Pd particles on silica by mild sonication, the catalysts were characterized by X-ray absorption spectroscopy and applied toward catalytic methanol decomposition. This reaction was determined as structure sensitive with the intrinsic activity (turnover frequency) increasing with increasing particle size. Moreover, observed catalytic deactivation was linked to product (carbon monoxide) poisoning. Co-feeding carbon dioxide caused the activity and the amount of deactivation to decrease substantially. A reaction mechanism based on the formation of the {pi}-bond between carbon and oxygen as the rate-limiting step is in agreement with antipathetic structure sensitivity and product poisoning by carbon monoxide.

Authors:
;  [1]
  1. (USF)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
OTHERUNIVERSITYOTHER U.S. STATES
OSTI Identifier:
1047891
Resource Type:
Journal Article
Journal Name:
ACS Catal.
Additional Journal Information:
Journal Volume: 2; Journal Issue: (6) ; 06, 2012; Journal ID: ISSN 2155-5435
Country of Publication:
United States
Language:
ENGLISH
Subject:
10 SYNTHETIC FUELS; ABSORPTION SPECTROSCOPY; CARBON; CARBON DIOXIDE; CARBON MONOXIDE; CATALYSIS; CATALYSTS; DEACTIVATION; METHANOL; NUCLEATION; OXYGEN; PALLADIUM; PARTICLE SIZE; POISONING; REACTION KINETICS; REGULATIONS; SENSITIVITY; SILICA; VALENCE

Citation Formats

Hokenek, Selma, and Kuhn, John N. Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties. United States: N. p., 2012. Web. doi:10.1021/cs200689k.
Hokenek, Selma, & Kuhn, John N. Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties. United States. doi:10.1021/cs200689k.
Hokenek, Selma, and Kuhn, John N. Tue . "Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties". United States. doi:10.1021/cs200689k.
@article{osti_1047891,
title = {Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties},
author = {Hokenek, Selma and Kuhn, John N.},
abstractNote = {Monodisperse palladium particles of six distinct and controlled sizes between 4-16 nm were synthesized in a one-pot polyol process by varying the molar ratios of the two palladium precursors used, which contained palladium in different oxidation states. This difference permitted size control by regulation of the nucleation rate because low oxidation state metals ions nucleate quickly relative to high oxidation state ions. After immobilization of the Pd particles on silica by mild sonication, the catalysts were characterized by X-ray absorption spectroscopy and applied toward catalytic methanol decomposition. This reaction was determined as structure sensitive with the intrinsic activity (turnover frequency) increasing with increasing particle size. Moreover, observed catalytic deactivation was linked to product (carbon monoxide) poisoning. Co-feeding carbon dioxide caused the activity and the amount of deactivation to decrease substantially. A reaction mechanism based on the formation of the {pi}-bond between carbon and oxygen as the rate-limiting step is in agreement with antipathetic structure sensitivity and product poisoning by carbon monoxide.},
doi = {10.1021/cs200689k},
journal = {ACS Catal.},
issn = {2155-5435},
number = (6) ; 06, 2012,
volume = 2,
place = {United States},
year = {2012},
month = {10}
}