Nynke Krans

PhD Candidate
Employed since: October 2015
Phone: +31 6 49725157
Email: n.a.krans@uu.nl
Room: 4th floor study area



Fabrication of supported metal catalysts

Fischer-Tropsch synthesis (FTS) has been investigated extensively for the production of hydrocarbons, such as clean transportation fuels, from CO and H2 (syngas). Catalysts used for this reaction are often cobalt and iron nanoparticles, where small nanoparticles are essential for high catalytic activity.[1]

Iron nanoparticles used in FTS usually consist of Fe2O3 crystallites, doped with promoters that increase the reducibility of the nanoparticles, improve CO dissociation and increase stability. Fabricating iron nanocrystals (INCs) supported on multiwall carbon nanotubes (MWCNT) via colloidal route yields relatively sintering-resistant catalysts, see Figure 1A and 1B. These catalysts can be applied for Fischer-Tropsch to olefins (FTO) catalysis.[2] The carbon support choice is important, as oxidic supports with strong metal-support interactions can hinder the formation of carbides. Another advantage of carbon supports is that the surface properties can be tuned by oxidation, making them highly suitable supports for FTO as oxygen groups can suppress particle growth.[3]

The fabrication of metal (oxide) nanocrystals (NCs) via a colloidal route is a relatively new concept in catalysis and insight in the deposition on iron nanocrystals on CNTs is limited. Therefore, my research focusses on the fundamental study of the deposition of the metal (oxide) NC on a support material. The deposition is followed in situ with liquid phase TEM analysis, where a liquid flow between SiN membranes can be established, see Figure 1C.[4]

Figure 1. (A) Colloidal iron oxide nanoparticles of 8 nm, (B) distributed homogeneously over MWCNT. (C) A schematic representation of an in-situ liquid cell TEM experiment.

Zhang, Q. et al., ChemCatChem, 2, 1030-1058, (2007)
Casavola, M. et al., Adv. Func. Mater., 25, 5309-5319, (2015)
Eschemann, T. et al., J. Catal., 328, 130-138 (2015).
Klein, K.L. et al., J. of Microscopy, 242, 117-123, (2010)



2015 – Present:
PhD research at the Inorganic Chemistry and Catalysis group of Utrecht University under supervision of Prof. K.P. de Jong and Dr. J. Zečević
Recent Topic: “Fabrication of supported metal catalysts”

Internship at Johnson Matthey – Sonning Common

Master degree in Nanomaterials, Chemistry and Physics
Thesis: “Synthesis of Colloidal Titania Cubes”

Bachelor degree in Chemistry at Utrecht University
Thesis: “Catalyst Synthesis, Elucidating the Impact of Drying”

High school education VWO at Stedelijk Dalton College Zutphen

Born in Zutphen, The Netherlands


Weber, J L; Krans, N A; Hofmann, J P; Hensen, E J M; Zecevic, J; de Jongh, P E; de Jong, K P

Effect of proximity and support material on deactivation of bifunctional catalysts for the conversion of synthesis gas to olefins and aromatics Journal Article

Catalysis Today, 342 , pp. 161-166, 2020, (cited By 2).

Links | BibTeX

Krans, N A; Weber, J L; Bosch, Van Den W; Zečević, J; Jongh, De P E; Jong, De K P

Influence of Promotion on the Growth of Anchored Colloidal Iron Oxide Nanoparticles during Synthesis Gas Conversion Journal Article

ACS Catalysis, 10 (3), pp. 1913-1922, 2020, (cited By 1).

Links | BibTeX

Lamme, W S; van der Heijden, O; Krans, N A; Nöllen, E; Mager, N; Hermans, S; Zečević, J; de Jong, K P

Origin and prevention of broad particle size distributions in carbon-supported palladium catalysts prepared by liquid-phase reduction Journal Article

Journal of Catalysis, 375 , pp. 448-455, 2019, (cited By 0).

Links | BibTeX

Krans, N A; Ahmad, N; Alloyeau, D; de Jong, K P; Zečević, J

Attachment of iron oxide nanoparticles to carbon nanofibers studied by in-situ liquid phase transmission electron microscopy Journal Article

Micron, 117 , pp. 40-46, 2019, (cited By 1).

Links | BibTeX

Krans, N A; van der Feltz, E C; Xie, J; Dugulan, I A; Zečević, J; de Jong, K P

Attachment of Iron Oxide Nanoparticles to Carbon Nanotubes and the Consequences for Catalysis Journal Article

ChemCatChem, 10 (16), pp. 3388-3391, 2018, (cited By 2).

Links | BibTeX

Deelen, Van T W; Nijhuis, J J; Krans, N A; Zečević, J; Jong, De K P

Preparation of Cobalt Nanocrystals Supported on Metal Oxides to Study Particle Growth in Fischer-Tropsch Catalysts Journal Article

ACS Catalysis, 8 (11), pp. 10581-10589, 2018, (cited By 0).

Links | BibTeX

Oschatz, M; Krause, S; Krans, N A; Mejía, Hernández C; Kaskel, S; Jong, De K P

Influence of precursor porosity on sodium and sulfur promoted iron/carbon Fischer-Tropsch catalysts derived from metal-organic frameworks Journal Article

Chemical Communications, 53 (73), pp. 10204-10207, 2017, (cited By 4).

Links | BibTeX

Oschatz, M; Hofmann, J P; van Deelen, T W; Lamme, W S; Krans, N A; Hensen, E J M; de Jong, K P

Effects of the Functionalization of the Ordered Mesoporous Carbon Support Surface on Iron Catalysts for the Fischer–Tropsch Synthesis of Lower Olefins Journal Article

ChemCatChem, 9 (4), pp. 620-628, 2017, (cited By 12).

Links | BibTeX

Casavola, M; Xie, J; Meeldijk, J D; Krans, N A; Goryachev, A; Hofmann, J P; Dugulan, A I; Jong, De K P

Promoted Iron Nanocrystals Obtained via Ligand Exchange as Active and Selective Catalysts for Synthesis Gas Conversion Journal Article

ACS Catalysis, 7 (8), pp. 5121-5128, 2017, (cited By 6).

Links | BibTeX

Munnik, P; Krans, N A; Jongh, De P E; Jong, De K P

Effects of drying conditions on the synthesis of Co/SiO2 and Co/Al2O3 fischer-tropsch catalysts Journal Article

ACS Catalysis, 4 (9), pp. 3219-3226, 2014, (cited By 31).

Links | BibTeX