Elucidating the role of potassium addition on the surface chemistry and catalytic properties of cobalt catalysts for ammonia synthesis.

Autor:	Ronduda H; Warsaw University of Technology, Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland hubert.ronduda@pw.edu.pl +48 22 234 7602., Zybert M; Warsaw University of Technology, Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland hubert.ronduda@pw.edu.pl +48 22 234 7602., Patkowski W; Warsaw University of Technology, Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland hubert.ronduda@pw.edu.pl +48 22 234 7602., Ostrowski A; Warsaw University of Technology, Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland hubert.ronduda@pw.edu.pl +48 22 234 7602., Sobczak K; University of Warsaw, Biological and Chemical Research Centre Żwirki i Wigury 101 02-089 Warsaw Poland., Moszyński D; West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering Pułaskiego 10 70-322 Szczecin Poland., Raróg-Pilecka W; Warsaw University of Technology, Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland hubert.ronduda@pw.edu.pl +48 22 234 7602.
Jazyk:	angličtina
Zdroj:	RSC advances [RSC Adv] 2024 Jul 22; Vol. 14 (32), pp. 23095-23108. Date of Electronic Publication: 2024 Jul 22 (Print Publication: 2024).
DOI:	10.1039/d4ra04517c
Abstrakt:	The ammonia synthesis process produces millions of tons of ammonia annually needed for the production of fertilisers, making it the second most produced chemical worldwide. Although this process has been optimised extensively, it still consumes large amounts of energy (around 2% of global energy consumption), making it essential to improve its efficiency. To accelerate this improvement, research on catalysts is necessary. Here, we studied the role of potassium in ammonia synthesis on cobalt catalysts and found that it was detrimental to the catalytic activity. It was shown that, regardless of the amount of introduced K, the activity of the K-modified catalysts was much lower than that of the undoped catalyst. K was found to be in the form of oxide; however, it was unstable and reducible to metallic K, which easily volatilised from the catalyst surface under activation conditions. In addition, potassium doping resulted in the sintering of the catalyst, the decrease in the surface basicity, and contributed to the loss of the active sites, mainly due to the coverage of Co surface by residual K species. Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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