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Vanadium Hydride as an Ammonia Synthesis Catalyst
Author(s) -
Cao Yu,
Saito Ayaka,
Kobayashi Yoji,
Ubukata Hiroki,
Tang Ya,
Kageyama Hiroshi
Publication year - 2021
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.202001084
Subject(s) - hydride , catalysis , vanadium , transition metal , inorganic chemistry , ammonia , chemistry , nitride , diffusion , materials science , crystallography , metal , organic chemistry , thermodynamics , physics , layer (electronics)
Early 3 d transition metals, such as Ti, V, or Nb are known to be inactive for the Haber‐Bosch process, due to their strong M−N bonds. However, recently some hydride compounds have been found to effectively counteract this effect, imparting catalytic activity on a wide range of elements. With these hydride catalysts, hydride (and nitride) bulk diffusion mechanisms have been proposed; if so, more open structures should enhance their activity. Here, we expand the study to hydrides of other early transition metals, V and Nb. These metals benefit from body‐centered cubic (bcc) related structures which enhance hydride diffusion, in addition to having relatively lower M−N bond strengths. The activity of vanadium hydride, most likely with an active composition of VH 0.44 N 0.16 , is superior to the previously reported BaTiO 2.5 H 0.5 , and comparable to TiH 2 and Cs−Ru/MgO at 400 °C under 5 MPa. These results show that there is more potential for developing new single‐phase hydride catalysts of previously overlooked elements without sacrificing activity.