Ramakrishna Kotni

Leonard S. Ornstein Laboratory, room 0.56
Princetonplein 1, 3584 CC Utrecht
P.O. Box 80 000, 3508 TA Utrecht
The Netherlands
phone: +31 (0)30 253 2320
secretariat: +31 (0)30 253 2952


Promotor: Prof. dr. Alfons van Blaaderen
Funding: MCEC
Employed: 15 January 2016 – 14 January 2020

Supraparticles for Catalysis

Fischer-Tropsch (FT) synthesis is an important industrial process which converts syngas (mixture of H2 and CO) to liquid fuels and fine chemicals with wide range of applications in different fields of science. Several transition metals like iron, cobalt, nickel, and ruthenium can be used as a FT catalysts; however, among these catalysts iron and cobalt are most prominently used in FT catalysis due to low cost, high activity and selectivity. The activity of these catalysts is highly influenced by particle size (high surface area), porosity, and high thermal stability. There are several methods have been proposed to improve the catalyst performance, however search for new method to design highly efficient and active catalyst is still in interest.

Here in this project we want to optimize  the  best conditions  for  the  controlled  synthesis  of  highly  monodisperse  Nanoparticles  (controlled  size, shape and composition) for FT catalysis [1]. The main objective of this project is to study the self-assembly of colloidal nanoparticles under constrained conditions. We will use the drying emulsion droplet method to induce self-assembly of nanoparticles (NP’s) by providing spherical confinement [2,3]. We intend to produce relatively monodisperse emulsions of dispersions by exploring visco-elastic high shear processing or microfluidic techniques.  More focus will be drawn towards the binary supraparticles (SP’s) self-assembly, where one of the components consists of monodisperse core-shell Fe-Co-oxide nanoparticles for (C1) FT catalysis and silica or polymer particles as another component. Further we will study the porosity of the SP for heat or chemical flows. Part of the project deals with improving thermal stability of the catalytic NPs by coating with mesoporous silica.

Figure 1: (a, b) TEM images of Ironoxide nanoparticles (scale bar is 100 nm). (c) A spherical supraparticle from self-assembly (scale bar is 1 µm).


[1] P. Munnik et al., Journal of American Chemical Society 136, 7333 (2014)

[2] V. Manoharan et al., Science 301, 483-7 (2003)

[3] B. de Nijs et al., Nature Materials 14, 56-60 (2014)