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Carbidisation of Pd Nanoparticles by Ethene Decomposition with Methane Production
Author(s) -
Jones Wilm,
Wells Peter. P.,
Gibson Emma K.,
Chutia Arunabhiram,
Silverwood Ian P.,
Catlow C. Richard A.,
Bowker Michael
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201900795
Subject(s) - disproportionation , dehydrogenation , methane , chemistry , carbide , adsorption , palladium , molecule , dissociation (chemistry) , nanoparticle , materials science , catalysis , inorganic chemistry , photochemistry , organic chemistry , nanotechnology
In the presence of oxygenated organic molecules pure Pd, which is widely used in chemicals processing and the pharmaceutical industry, tends to defunctionalise and dehydrogenate such molecules to H 2 , CO and surface/bulk carbon, in the form of a palladium carbide. We have investigated the formation of this carbide by ethene adsorption using a variety of techniques, including pulsed flow reaction measurements, XAS and DFT calculations of the lattice expansion during carbidisation. These experiments show that two main reactions take place above 500 K, that is, both total dehydrogenation, but also disproportionation to methane and the carbide, after which the activity of the Pd is completely lost. We estimate the value of x in PdC x to be 0.28 (±0.03), and show by computer modelling that this fits the lattice expansion observed by XAFS, and that there is charge transfer to C from Pd of around 0.2–0.4 e.