Nynke Krans

PhD Candidate

Employed since: October 2015
Phone: +31 6 49725157
E-mail: n.a.krans@uu.nl
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.

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