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MS dopants DR Rev1 ChemRxiv.pdf (2.72 MB)

Impact of small promoter amounts on coke structure in dry reforming of methane over Ni/ ZrO2

revised on 20.05.2020, 14:03 and posted on 21.05.2020, 06:33 by Robert Franz, Tobias Kuehlewind, Genrikh Shterk, Edy Abou-hamad, Alexander Parastaev, Evgeny Uslamin, Emiel J.M. Hensen, Freek Kapteijn, Jorge Gascon, Evgeny Pidko
Coke deposition is one of the main challenges in the commercialisation of dry reforming of methane over supported Ni catalysts. Besides the coke quantity, the structure of the deposits is also essential for the catalyst lifetime. Accordingly, in this study, we analysed the effect of Na, K, and Cs promoters on both these variables over Ni/ ZrO2 catalysts. Besides blocking the most active coke-forming sites already at low loading, the promoting effect of the alkali metals is also contributed by their coke gasification activity. To evaluate the additional impact of the latter, the behaviour of alkali-doped catalysts was compared to that for Mn-doped catalysts, exclusively featuring the site-blocking promotion mechanism. While the conversion is barely affected by the type of promoter, it has a profound effect on the amount and the composition of carbon deposits formed during the reaction. Promoting with K or Mn reduces the coke content to a similar degree but with less carbon fibres observed in the case of K. The promotion by Cs and Na results in the lowest coke content. The superior performance of Cs and Na-doped Ni/ZrO2 catalysts is attributed to the enhanced coke gasification via carbonate species on top of the site blocking effects.


Email Address of Submitting Author


Delft University of Technology


The Netherlands

ORCID For Submitting Author


Declaration of Conflict of Interest

no conflict of interests

Version Notes

revision 1