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Large Oblate Hemispheroidal Ruthenium Particles Supported on Calcium Amide as Efficient Catalysts for Ammonia Decomposition
Author(s) -
Kishida Kazuhisa,
Kitano Masaaki,
Inoue Yasunori,
Sasase Masato,
Nakao Takuya,
Tada Tomofumi,
Abe Hitoshi,
Niwa Yasuhiro,
Yokoyama Toshiharu,
Hara Michikazu,
Hosono Hideo
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201800467
Subject(s) - decomposition , catalysis , ammonia , chemistry , ruthenium , alkali metal , inorganic chemistry , particle (ecology) , particle size , metal , organic chemistry , oceanography , geology
Ammonia decomposition is an important technology for extracting hydrogen from ammonia toward the realization of a hydrogen economy. Herein, it is reported that large oblate hemispheroidal Ru particles on Ca(NH 2 ) 2 function as efficient catalysts for ammonia decomposition. The turnover frequency of Ru/Ca(NH 2 ) 2 increased by two orders of magnitude when the Ru particle size was increased from 1.5 to 8.4 nm. More than 90 % ammonia decomposition was achieved over Ru/Ca(NH 2 ) 2 with large oblate hemispheroidal Ru particles at 360 °C, which is comparable to that of alkali‐promoted Ru catalysts with small Ru particle sizes. XAFS analyses revealed that Ru particles are immobilized on Ca(NH 2 ) 2 by Ru−N bonds formed at the metal/support interface, which lead to oblate hemispheroidal Ru particles. Such a strong metal–support interaction in Ru/Ca(NH 2 ) 2 is also substantiated by DFT calculations. The high activity of Ru/Ca(NH 2 ) 2 with large Ru particles primarily originates from the shape and appropriate size of the Ru particles with a high density of active sites rather than the electron‐donating ability of Ca(NH 2 ) 2 .