Projects at Utrecht University | Projects by Alfons van Blaaderen

All projects by Prof. Alfons van Blaaderen (UU):

Multiscale Structuring for 2-Step Catalysis & Sensing

Photocatalysis Enhanced by 3D Multi-Scale Structured Supraparticles (SPs)

Molecular simulations of nanoparticles and heterogeneous catalytic surfaces in a solution

Nanoprobes for high resolution spatial and temporal temperature mapping

About Alfons van Blaaderen

 


Multiscale Structuring for 2-Step Catalysis & Sensing
Joint Doctorate
1st supervisor and 1st promotor: Prof. Alfons van Blaaderen (UU)
2nd supervisor and co-promotor: Associate Prof. Mathieu Odijk (UT)
2nd promotor: Prof. Albert van den Berg (UT)
Affiliation: Utrecht University and University of Twente
Research theme: Catalyst Diagnostics to Develop More Active Catalysts

Structuring heterogeneous catalysts at multiple length scales to enhance performance at multiple levels is at the heart of the MCEC consortium. Here we want to exploit recent advances in the field of microfluidics, where droplets are made on chips, with hierarchical self-assembly (SA). In this project we want to use slowly drying dispersion droplets consisting of two types of nanoparticles to generate submicron sized well-ordered, binary ‘supraparticles’ (SPs) on gram-scale.

Subsequently, we will SA different types of such colloidal SPs into small clusters (e.g. 2, 3 or 4 SPs) with enhanced functionality that stems from the two different types of SPs (also using monodisperse droplets to perform the SA). We will focus on two types of added functionalities made possible by the structuring at several length scales: 1) we want to create SP clusters where a 2-step catalytic reaction can be performed; 2) we will create SP clusters which allow surface-enhanced-Raman-Scattering (SERS) to be enhanced and used on the products of the attached catalytic SP.

These are however examples of applications of a general strategy to create on gram-scale heterogeneous catalysts / sensing platforms using highly parallelized microfluidic sub-micrometer droplet generators used for the first time with dispersions of nanoparticles.

Keywords:

  • Self-assembly
  • Microfluidics
  • Sensing
  • Colloids
  • Microscopy

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Photocatalysis Enhanced by 3D Multi-Scale Structured Supraparticles (SPs)
Joint Doctorate
1st supervisor and 1st promotor: Prof. Alfons van Blaaderen (UU)
2nd supervisor and 2nd promotor: Prof. Rob Lammertink (UT)
Affiliation: Utrecht University and University of Twente
Research theme: Smart Biomass Conversion

Structuring heterogeneous catalysts at multiple length scales to enhance performance at multiple levels is at the heart of the MCEC consortium. Here we want to make several micrometer sized particles build up from two kinds of smaller nano-particles, one being composed of titanium dioxide (spheres and rods) and the other being silica or a noble metal particle (e.g Pt). By having these small nanoparticles self-assemble inside drying droplets, micron-sized ‘supraparticles’ will be made in which light can by multiple scattering form so-called Mie Whispering Gallery resonances.

Recently we have shown that this enhancement can lead to supraparticles that support lasing! With these resonances light can be made to interact stronger with the catalyst within the supraparticle, thus enhancing photocatalysis (e.g. water splitting). Moreover, by structuring of the two nanoparticle components within the SP on catalyst length scale (e.g. patches of catalytic material next to non-catalytic surface area) we want to improve the catalysis by creating local convection currents to enhance transport.

The proof of concept of this enhanced convective transport on structures titania catalysts has been demonstrated in 2D and will be extended into 3D catalytic assemblies guided by calculations and simulations.

Keywords:

  • Self-assembly
  • Photo-catalysis
  • Enhanced convection
  • Colloids
  • Confocal microscopy

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Molecular simulations of nanoparticles and heterogeneous catalytic surfaces in a solution
Joint Doctorate
1st supervisor and 1st promotor: Prof. Marjolein Dijkstra (UU)
2nd promotor: Prof. Alfons van Blaaderen (UU)
2nd supervisor: Prof. Rob Lammertink (UT)/Prof. Detlef Lohse (UT)
Affiliation: Utrecht University and University of Twente
Research theme: Smart Biomass Conversion

To control the self-assembly of colloidal nanoparticles for heterogeneous catalyst systems, it is important to obtain a better understanding of the surface and shape morphology of nanoparticles and their effective interactions in 3D and in solution. We will use molecular simulations to determine the effective interactions of silica and metal(-oxide) nanoparticles capped with ligands, e.g., oleic acids or dendrimers, in various solvents. The interactions obtained from simulations will be compared with the nanoparticle potential measurements by the experimental group of Alfons van Blaaderen by measuring the 3D radial distribution function of “frozen-in” nanoparticle suspensions.

In addition, we will use molecular simulations and numerical calculations to study the local enhanced stirring due to electro/diffusion-osmotic flows in the vicinity of a structured catalytic and non-catalytic surface, which can be used to enhance the catalytic turn-over as compared to a fully coated catalyst surface. We will compare our results with those of a twin project of the experimental group of Rob Lammertink (UT), and the numerical calculations carried out by the group of Detlef Lohse (UT) and Hans Kuipers (TU/e). Finally, we will also study the enhanced diffusion in a 3D heterogeneously structured environment of a binary crystal of catalytic and non-catalytic particles, which is relevant for the experiments carried out in the group of Alfons van Blaaderen (UU).

Keywords:

  • Self-assembly
  • Molecular Simulations
  • Nanoparticles
  • Interaction Potentials
  • Enhanced Convection

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Nanoprobes for high resolution spatial and temporal temperature mapping
1st supervisor and 1st promotor: Prof. Andries Meijerink
2nd supervisors: Prof. Alfons van Blaaderen and Prof. Bert Weckhuysen
2nd promotor: Prof. Bert Weckhuysen
3rd promotor: Prof. Alfons van Blaaderen
Affiliation: Utrecht University
Research theme: Catalyst Diagnostics to Develop More Active Catalysts

Temperature plays a crucial role in the efficiency and selectivity of chemical reactions. Optimization of temperature for a specific reaction often assumes a homogeneous temperature distribution but in reality there are large variations due to non-uniform mass and heat transport. Mapping temperature profiles with high spatial and temporal resolution is a first step in understanding and controlling temperature profiles in order to optimize the reactor performance.

In this project lanthanide-doped nanoparticles are used for remote temperature sensing using luminescence spectroscopy. Luminescent nanoprobes will be incorporated in catalytically active particles in real chemical reactors and remote excitation and collection of the emission enables accurate mapping of 3D temperature profiles. The highly temperature dependent emission spectra of different lanthanide ions in different nanocrystalline host materials allow for application in different temperature ranges and in a variety of chemical reactors, including microfluidics.

Confocal microscopy will be employed to measure local temperature variations on the sub-micrometer scale related to processes in individual catalytically active particles. The project will provide new insight in temperature variations over a wide range of length scales (micrometer to meter) and aid in the optimization of heat flows in chemical reactors.

Keywords:

  • Temperature sensing
  • Nanoparticle
  • Luminescent Lanthanide
  • Microfluidic Reactor
  • Confocal microscopy

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About Alfons van Blaaderen

Professor Alfons van Blaaderen is Full Professor at the Debye Institute for Nanomaterials Science of Utrecht University (The Netherlands).

He studied Chemistry and, after his PhD, Physics at Utrecht University and obtained his Master Degree cum laude (highest degree) in 1987. He continued at the same university with a PhD study under the supervision of Prof. Vrij, and was awarded the PhD degree cum laude (highest degree) in 1992. He was a postdoctoral fellow at Utrecht University with Prof. Lekkerkerker from 1991-1993 and at AT&T Bell Laboratories in Murray Hill (USA) with Dr. Wiltzius and Dr. Murray from 1994-1995. From 1995 he worked for 8 years at the FOM Institute AMOLF as group leader (for 50% of his time). He became associate professor in the group of Prof. Lekkerkerker at Utrecht University in 1997 and rose to the rank of full professor in the field of (Soft) Condensed Matter Physics at the same university in the Physics Department in 1999. Van Blaaderen (co-) authored ~ 165 publications in peer-reviewed journals with an average number of citations per paper of ~ 60 and a Hirsch index of 54; 33% of all his papers are journals with an impact factor > 7. Furthermore, van Blaaderen is the (co-) author of 5 popular publications and 5 book chapters and holds 5 patents/patent applications.

The research group of van Blaaderen makes seminal contributions to the field of (soft) condensed matter and in particular its subfield colloid science, fields that are multidisciplinary in nature encompassing Chemistry, Physics and Materials Science. However, the research work also spill over to neighboring fields like (micro-) biology and granular matter, where quantitative microscopy and use of particles are also often important tools.

Van Blaaderen obtained a prestigious TOP CW NWO (2005) grant from The Netherlands Science Foundation (NWO) and an Advanced ERC grant (2011) from the European Research Council and leads two FOM (Dutch Physics Science Foundation) programs. He also has received several research awards, including, the 1992 DSM Prize for Best Dutch/Belgian Chemistry PhD Thesis, the 2006 Rhodia Prize from the European Colloid and Interface Science Society and the 2011 Peter Debye Prize from the Edmond Hustinx foundation. The Soft Condensed Matter & Biophysics section he leads obtained twice in a row a ‘maximum’ score of 4x’5’ at the 5 year national Physics evaluation by an international jury. Van Blaaderen serves(d) on several boards and panels for research, including the TWINS council of the Royal Academy of Sciences (KNAW), the Dutch Nano Initiative, and COMOP council of (FOM, part of NWO). In 2007 he co-wrote for NWO a strategic report on Nanoscience. He was asked four times by the journals Science and Nature to comment in News and Views on new results in the field of colloid science. He was visiting Professor in 2006 at the Soft Matter Center (NYU, New York, USA) and 2012 distinguished visiting Professor at the Chemistry Institute of the Chinese Academy of Sciences (Beijing, China). He was scientific director of the Debye Institute for Nanomaterials Science (2008-2012) and became in 2013 elected member of the KNAW.

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