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State of supported Pd during catalysis in water

Chase, Zizwe A. ; Fulton, John L. ; Camaioni, Donald M. ; Mei, Donghai ; Balasubramanian, Mahalingam ; Pham, Van-Thai LU ; Zhao, Chen ; Weber, Robert S. ; Wang, Yong and Lercher, Johannes A. (2013) In Journal of Physical Chemistry C 117(34). p.17603-17612
Abstract


The structure and chemical state of supported Pd nanoparticles in contact with H
2
in the aqueous phase have been explored by X-ray absorption spectroscopy to better understand their surface reactivity in polar condensed media. The Pd-Pd distances at substantial H
2
pressures indicate the presence of sorbed hydrogen and point to the presence of Pd hydrides, proving that such nanoparticles are hardly influenced by the presence of water. During the hydrogenation of the reactants (phenol, cyclohexanone, and cyclohexene), the Pd-Pd bond length decreased,... (More)


The structure and chemical state of supported Pd nanoparticles in contact with H
2
in the aqueous phase have been explored by X-ray absorption spectroscopy to better understand their surface reactivity in polar condensed media. The Pd-Pd distances at substantial H
2
pressures indicate the presence of sorbed hydrogen and point to the presence of Pd hydrides, proving that such nanoparticles are hardly influenced by the presence of water. During the hydrogenation of the reactants (phenol, cyclohexanone, and cyclohexene), the Pd-Pd bond length decreased, indicating a drastically lower concentration of sorbed H compared to Pd in the absence of the reactants. This steady state concentration of sorbed hydrogen is established by all reactions involving H
2
, i.e., the sorption/desorption into the bulk, the adsorption at the surface, and the reaction with unsaturated reactants, but not by reaction with water. This demonstrates that neither the Pd particles nor the H/Pd ratio is influenced by water, but dynamically adapt to reaction conditions. Consistently, ab initio molecular dynamic simulations indicate that Pd-water interactions are relatively weak for Pd metal and that these interactions become even weaker, in the presence of H
2
and when hydrogen is incorporated into the metal particles.

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author
; ; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
in
Journal of Physical Chemistry C
volume
117
issue
34
pages
10 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:84883324141
ISSN
1932-7447
DOI
10.1021/jp404772p
language
English
LU publication?
no
id
c1763b16-87ef-42d3-b58d-c2c8dfb68f9e
date added to LUP
2019-06-30 09:42:55
date last changed
2022-01-31 22:55:42
@article{c1763b16-87ef-42d3-b58d-c2c8dfb68f9e,
  abstract     = {{<p><br>
                            The structure and chemical state of supported Pd nanoparticles in contact with H<br>
                            <sub>2</sub><br>
                             in the aqueous phase have been explored by X-ray absorption spectroscopy to better understand their surface reactivity in polar condensed media. The Pd-Pd distances at substantial H<br>
                            <sub>2</sub><br>
                             pressures indicate the presence of sorbed hydrogen and point to the presence of Pd hydrides, proving that such nanoparticles are hardly influenced by the presence of water. During the hydrogenation of the reactants (phenol, cyclohexanone, and cyclohexene), the Pd-Pd bond length decreased, indicating a drastically lower concentration of sorbed H compared to Pd in the absence of the reactants. This steady state concentration of sorbed hydrogen is established by all reactions involving H<br>
                            <sub>2</sub><br>
                            , i.e., the sorption/desorption into the bulk, the adsorption at the surface, and the reaction with unsaturated reactants, but not by reaction with water. This demonstrates that neither the Pd particles nor the H/Pd ratio is influenced by water, but dynamically adapt to reaction conditions. Consistently, ab initio molecular dynamic simulations indicate that Pd-water interactions are relatively weak for Pd metal and that these interactions become even weaker, in the presence of H<br>
                            <sub>2</sub><br>
                             and when hydrogen is incorporated into the metal particles.</p>}},
  author       = {{Chase, Zizwe A. and Fulton, John L. and Camaioni, Donald M. and Mei, Donghai and Balasubramanian, Mahalingam and Pham, Van-Thai and Zhao, Chen and Weber, Robert S. and Wang, Yong and Lercher, Johannes A.}},
  issn         = {{1932-7447}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{34}},
  pages        = {{17603--17612}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry C}},
  title        = {{State of supported Pd during catalysis in water}},
  url          = {{http://dx.doi.org/10.1021/jp404772p}},
  doi          = {{10.1021/jp404772p}},
  volume       = {{117}},
  year         = {{2013}},
}