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Production of Hydrogen from Dimethyl Ether over Supported Rhodium Catalysts
Author(s) -
Halasi Gyula,
Bánsági Tamás,
Solymosi Frigyes
Publication year - 2009
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.200900113
Subject(s) - dimethyl ether , rhodium , catalysis , chemistry , selectivity , dissociation (chemistry) , thermal decomposition , decomposition , infrared spectroscopy , inorganic chemistry , desorption , hydrogen , adsorption , photochemistry , nuclear chemistry , organic chemistry
Infrared (IR) spectroscopy revealed that dimethyl ether (DME) undergoes partial dissociation on pure and rhodium‐containing CeO 2 at 300 K to yield methoxy and methyl species. This process is promoted by the presence of rhodium. By means of thermal desorption measurements (TPD), the adsorption of DME on Rh/CeO 2 at 300 K and subsequent decomposition of DME ( T p ≈370 K), releasing H 2 , CO, CO 2 , and CH 4 , with T p between 420 and 673 K, were ascertained. Rh/CeO 2 is an effective catalyst for the decomposition of DME to give H 2 (29–35 %), CO (27–30 %) and CH 4 (32–38 %) as major products with complete conversion at 673–723 K. Adding water to DME changed the product distribution and increased the selectivity of H 2 formation from 30–35 % to 58 % at 723 K. In situ IR spectroscopy showed absorption bands of CO at 2034 and 1893 cm −1 during the reaction at 673–773 K. Deactivation of the catalyst did not occur at 773 K during the time measured (approximately 10 h). Rh deposited on carbon Norit also exhibited a high activity towards the decomposition of DME, but the selectivity towards hydrogen was lower.