Please use this identifier to cite or link to this item: https://hdl.handle.net/11147/7753
Title: Effect of ammonia on cobalt Fischer-Tropsch synthesis catalysts: A surface science approach
Authors: Kızılkaya, Ali Can
Niemantsverdriet, J. W.
Weststrate, C. J.
Kızılkaya, Ali Can
Izmir Institute of Technology. Chemical Engineering
Keywords: Fischer-Tropsch synthesis
Ammonia
Catalyst poisoning
Ammonia adsorption
Cobalt nanoparticles
Issue Date: May-2019
Publisher: Royal Society of Chemistry
Source: Kızılkaya, A. C., Niemantsverdriet, J. W., and Weststrate, C. J. (2019). Effect of ammonia on cobalt Fischer-Tropsch synthesis catalysts: A surface science approach. Catalysis Science and Technology, 9(3), 702-710. doi:10.1039/c8cy01723a
Abstract: Ammonia adsorption and decomposition on defect-rich hcp-Co(0001) surfaces were investigated under ultra-high vacuum conditions in order to provide a fundamental explanation for industrially observed ammonia poisoning of cobalt based Fischer-Tropsch synthesis (FTS) catalysts. Temperature-programmed desorption, infrared spectroscopy and work function measurements indicate that undercoordinated sites bind ammonia stronger than sites on flat Co(0001), and they also induce its dehydrogenation. Density functional theory calculations were employed to explore the reactivity of defective Co surfaces using the fcc-Co(211) as a model. The results indicate that the decomposition products (NH x ) adsorb strongly on or around the step site on fcc-Co(211). We find that NH (+2H ad ), adsorbed in the threefold site on the upper terrace, is equally stable as NH 2 (+H ad ), adsorbed in the bridge position at the step edge, both being significantly more stable than the equivalent species adsorbed on the flat Co(0001). The calculated activation barriers for NH 3,ad dehydrogenation steps are in reasonable agreement with the barriers obtained by fitting experimental data. Based on these fundamental insights, poisoning of cobalt nanoparticles during FTS by NH 3 contaminants can be linked mainly to the blocking of undercoordinated sites by strongly adsorbed NH 2 species.
URI: https://doi.org/10.1039/C8CY01723A
https://hdl.handle.net/11147/7753
ISSN: 2044-4753
2044-4753
Appears in Collections:Chemical Engineering / Kimya Mühendisliği
Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Files in This Item:
File Description SizeFormat 
c8cy01723a.pdfMakale (Article)2.92 MBAdobe PDFThumbnail
View/Open
Show full item record

CORE Recommender

WEB OF SCIENCETM
Citations

1
checked on Jul 31, 2021

Page view(s)

22
checked on Aug 4, 2021

Download(s)

16
checked on Aug 4, 2021

Google ScholarTM

Check

Altmetric


Items in GCRIS Repository are protected by copyright, with all rights reserved, unless otherwise indicated.