fulltext.study @t Gmail

Carbon-supported cobalt–iron catalysts for ammonia synthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
44055 46001 2006 5 PDF Available
Title
Carbon-supported cobalt–iron catalysts for ammonia synthesis
Abstract

The cobalt, iron and Co–Fe catalysts deposited on carbon were prepared, characterised (XRD, H2 TPD) and studied in ammonia synthesis at 90 bar (H2:N2 = 3:1). Partly graphitised carbon material obtained via high temperature treatment (1900 °C) of commercial activated carbon was used as a support for the active metals (10 wt.%) and barium or potassium were used as promoters. XRD studies of unpromoted materials have shown that cobalt (5–20% in Co + Fe) dissolves in the iron phase (alloy formation); the average sizes of crystallites (20–30 nm) are roughly independent of the metal kind (Co, Fe, Co–Fe). The effect of Ba and that of K on the catalyst performance proved to be strongly dependent on the choice of an active phase (Co or Fe or Co–Fe). In the case of Co/C, the promotional effect of barium was extremely large. Furthermore, the Ba–Co/C system was found to be less inhibited by the ammonia product than Ba–Fe/C. At low temperature (400 °C) and at high conversion (8% NH3 in the gas), the surface-based reaction rate (TOF) for Ba–Co/C is about six times higher than that for Ba–Fe/C.

Keywords
Ammonia synthesis; Cobalt–iron catalyst; Carbon support; Barium potassium promoter
First Page Preview
Carbon-supported cobalt–iron catalysts for ammonia synthesis
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 300, Issue 2, 26 January 2006, Pages 181–185
Authors
, , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis