RESEARCH GROUPS OF THE CHEMICAL ENGINEERING DEPARTMENT OF TU
DELFT
Advanced Soft Matter
The new Advanced Soft Matter (ASM) group combines parts of the old research groups
NanoStructured Materials and Self-Assembling Systems. The website of the new ASM group is
currently being updated, so visit us frequently to see the latest news.
The Advanced Soft Matter (ASM) research group is focused in particular on the development
and characterisation of new functional nanostructured components. Examples include biosensors,
self-healing materials, opto-electronic devices, nanocapsules - all of which are formed by
self-assembly or directed-assembly of molecular building blocks.
Materials of interest may range from (bio)organic to nanostructured inorganic materials and
hybrid systems.
The main challenge envisioned in this field is to upscale the principles of
self-assembly from nanostructures to large-scale production. This challenge requires research
on the theoretical level, involving for example numerical simulation methods,
and on the experimental level for which many characterization techniques are available in house
and at specialised facilities.
Our research is fundamental in nature but with a clear link to applications.
Catalysis Engineering
The Catalysis Engineering group focuses on the development & demonstration of
new catalysis and reactor engineering concepts devoted to sustainable technologies
with emphasis on process intensification, feedstock efficiency, and reduction of both
energy usage as well as the influence of human and industrial activities on the
environment.
Major Areas of Research:
Structured catalysts and -reactors & Zeolite Membranes
Advanced Functional Materials: Zeolites and Metal-Organic Frameworks
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Renewables: Smart Conversion Processes
In-situ catalyst characterisation (Spectroscopy, TEM, TAP)
Photo-& ElectroCatalysis
Organic materials and interfaces
Our research interest at the OMI group lies at solid-liquid, solid-gas and solid-solid
interfaces with an emphasis on the control and fine-tuning of the interface
properties. This can be achieved, for example, by an induced change of the physical
properties of the interface or by surface (bio) functionalization. We study and
develop a range of different surface modifications and their characterizations. We
mainly focus on fundamental chemistry with a clear direction toward viable
applications, such as:
(Bio)chemical sensors (Dr Louis de Smet and Dr Liza Rassaei)
A variety of solid
transducer surfaces (silicon nanowires, diamond, glass, gold and other metals) are
functionalised with (bio)organic molecules. This modification enhances the sensitivity
and selectivity of the surface for binding or recognition of certain chemical or
biochemical analytes. The (bio)recognition event results in changes in the interface
properties, which can be detected, for example, via monitoring e.g. electrical
currents (I), electrical impedance (Z) or the refractive index (n) properties.
Photovoltaics and photolysis of water (Dr Wolter Jager)
Dedicated chromophore
assemblies, which absorb major parts of the solar spectrum, are synthesized and
chemically connected to surfaces for obtaining a photovoltage. These chromophore
assemblies, if connected to a properly chosen catalyst, are also utilised for the
photo-splitting of water into hydrogen and oxygen, thus producing ‘solar fuel’ as a
renewable energy carrier.
Biofuel cells (Dr Liza Rassaei)
Enzymes as biocatalysts can be integrated in surface
structures to directly convert the chemical energy present in biomass into electrical
energy. The power output of a biofuel cell is determined, amongst others, by the
electrode properties, the enzyme turnover rates, their stability and life time, and the
electron transfer pathway during the reactions.
Complex fluids, colloids and interfaces (Dr ir Klaas Besseling)
Interfaces
between solids and complex fluids e.g. solutions of (combinations of) polymers,
associative molecules and self-assembling molecular structures are crucial in a wide
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range of applications, ranging from paints to medicine, and from sensors to nanocomposite materials. The focus in this research is to achieve control over these
systems by resolving the mechanisms that determine their behaviour: ‘When you
know how it works, you know how to get what you want.’ We do this by making use
of, and extending the fundamental concepts of the physical chemistry of soft matter
systems.
Composite lithium-ion battery materials (Dr Erik Kelder)
Composite materials of
organic and inorganic origin are studied to obtain solutions for sustaining the
mechanical and chemical behavior of lithium-ion batteries during charging and
decharging cycles. Within the research novel polymers are being developed to
enhance the energy storage density, the power performance and life time of
rechargeable batteries, based on the lithium-air concept. The research is a
cooperation between the OMI group and the Radiation Science and Technology
Department.
Polymer (nano)composites (Prof dr Theo Dingemans)
All-aromatic
polymers are designed, synthesized and characterized to optimise the non-covalent
interactions between the polymer chains mutually and with the added reinforcing
phase. The research is focussed reinforcing phases based on nano-sized carbon
materials, like single- and multi-walled carbon nanotubes and graphene. The
research is a cooperation between the OMI group and the Aerospace Engineering
Department.
Opto-electronic materials
Our research aims to provide fundamental insight into the relation between the
properties of excitons and charge carriers and the physico-chemical structure of
materials. In order to achieve this a variety of time-resolved techniques are used.
Charge carriers and electronically excited states are generated using pulsed laser
systems or an electron accelerator. The properties of these charges and excited
states are studied on times scales ranging from femtoseconds to microseconds by
optical spectroscopy, microwave/terahertz conductivity measurements, and several
other opto-electronic techniques. The experimental work in the section is supported
by theoretical studies, including electronic structure calculations, molecular dynamics
simulations and simulations of charge and exciton transport.
Charge carrier multiplication in semiconductor nanoparticles
The dynamics of excitons and charges in semiconductor nanoparticles (quantum
dots) are investigated by femtosecond transient optical absortion measurements and
by terahertz conductivity experiments.
Charge transport along isolated molecular wires
Time-resolved microwave conductivity measurements are performed in order to
study the motion of charges along isolated conjugated polymer chains in solution.
Charge transport in solid nano-structured materials
The charge transport properties of organic and inorganic materials for opto-
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electronic applications are studied in the solid state by microwave conductivity
measurements. The charges are either generated in the bulk solid by irradiation with
an electron accelerator or in thin films by photoexcitation.
Optical properties of charged species in opto-electronic materials
The optical absorption spectra of charged species in materials for optoelectronics are
studied by nano-second time-resolved optical absorption spectroscopy.
Exciton diffusion and dissociation in hybrid organic/(in)organic systems
for photovoltaics
The dynamics of excitons and charges in organic/(in)organic combinations of
materials are studied in thin films, either on the nanosecond time scale by timeresolved microwave conductivity measurements on a femtosecond time scale by
transient optical or terahertz absorption experiments.
Computational studies of opto-electronic materials
Theoretical studies are carried out to understand and predict the nature and
dynamics of charge carriers and excitons in opto-electronic materials.
Product and Process engineering
Product and Process Engineering (PPE) views chemical engineering as an expanding
field full of opportunities to create devices, processes and products. With expertise in
reaction engineering, fluid mechanics and transport phenomena, we create solutions
for soft-matter, nanotechnology, energy and lab-on-chip applications, often together
with chemistry, physics and life-science groups; we love interdisciplinary projects.
For us, engineering implies out-of-the-box thinking and design, from a sound basis in
natural sciences with mathematical rigor.
A partial list of topics we work on:
 bubbles, drops and cells in laboratories-on-chip
 partial wetting in microfluidic devices
 spatio temporal pattern formation in porous media
 rational design and synthesis of core-shell nanoparticles
 light intensity in photocatalytic reactors
 behavior of particles in turbulent gas/liquid systems
 granular matter in dense fluidized flows
Transport phenomena
The Transport Phenomena group studies the transport of mass, momentum and
heat, on different length and time scales, in physical and chemical processes related
to advanced materials processing, energy conversion and storage, and health. The
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main interest is in transport phenomena around (solid-fluid, liquid-gas and liquidliquid) interfaces, which we wish to understand, control and enhance.
The group uses both theoretical and computational models, and non-intrusive
experiments based on laser and X-ray techniques.
Our expertise is in heat and mass transfer in multiphase flows, turbulent flows,
microflows and biological flows.
A partial list of topics which we currently work on:
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Multiphase flow and dynamic contact line phenomena in digital microfluidics
and Labs-on-Chips
Dispersed multiphase flows in large scale chemical processing (bubble
columns, fluidized beds, Fischer Tropsch)
Magnetohydrodynamics in advanced liquid metal processing (welding,
casting)
Magnetic drug targeting
Oil-water separation
Turbulence modulation for enhanced heat and mass transfer
Materials for Energy Conversion and Storage
The MECS group focuses on the development of new materials for sustainable
energy applications. Taking a materials science approach, we explore the relation
between synthesis, structure and physical properties. Intensively exploring and
exploiting the benefits that nanostructuring offers for sustainable energy solutions,
we also evaluate possible adverse effects nanoparticulate materials may have on
humans and nature. Our major research themes are Hydrogen (storage, sensing,
etc.) and Solar Fuel (water splitting, CO2 reduction). Our long term aim is to build a
photoelectrochemical device to convert water and CO2 into substances of higher
energy content such as syngas. We seek to maintain a unique position in developing
and employing a wide range of nano-particle and thin film and preparation
techniques such as Sputter Deposition, Atomic Layer Deposition, Spray Pyrolysis and
spark ablation. Optical characterization includes Raman, Ellipsometry, in-situ UV/VIS
spectroscopy, mobility based nanoparticle characterization and a electrochemistry lab
including a solar simulator.
Research projects:
Hydrogenography to optimize metal hydride storage materials
Hydrogenography is a combinatorial thin film technique which allows us to screen
the thermodynamic and kinetic properties of hydrogen chemisorption optically. After
deposition of a compositional gradient thin film we analyze the hydrogenation
properties of hundreds of metal alloy compositions simultaneously by analyzing the
optical transmission.
As a result we are able to analyze the compositional dependence of the equilibrium
pressure over a wide proportion of e.g. the ternary phase diagram of Mg-Ni-Ti. By
measuring the equilibrium pressure over a wide temperature range and plotting the
resulting Van ‘t Hoff relation, we obtain the related enthalpy of formation
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Presently we are investigating:
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The validation of the method by investigating Pd thin films. We find a perfect
matching with bulk values of both the enthalpy and entropy of formation.
The role of the substrate and the resulting clamping. Substrate-film
interaction induces an increased hysteresis. This can be minimized by adding
an intermediate Pd thin film.
Ways to enhance the kinetics of the hydrogenation by chemical tuning and
the use of proper catalysts
Ways to destabilize the metal hydride in order to tune the vapor pressure to
the values required by fuel cells
The determination of the critical temperature in Pd-based membranes
Optical fiber hydrogen sensors/detectors
With the increasing number of hydrogen applications the need for safety detectors
increases. The current generation of hydrogen detectors is large in size and generally
relies on an electrical readout at the area of measurement.
We focus on optical hydrogen detection using smart-coatings at the top of an optical
fiber. Optical fibers have the advantage that they can be read at a distance and due to their small size- many of them can be readout in parallel with a single
detector.
Current research:
Presently we are investigating the role of impurities in the
atmosphere on the reliability of the detector. Furthermore, we are developing a
hydrogen sensor based on the same principle. Instead of a binary detection, the
sensor give a variable optical output over a certain hydrogen pressure range.
Photoelectrochemical water splitting
Doped Transition Metal Oxides for Photoelectrolysis
Splitting water into hydrogen and oxygen with sunlight represents one of the few
truly clean and sustainable energy sources. While this can be achieved by coupling a
PV solar cell to an electrolyzer, this option is economically unattractive. A low-cost
alternative is the use of a semiconductor in a photoelectrochemical (PEC) cell. When
illuminating a semiconductor that is immersed in water, oxygen bubbles can evolve
from one side, while hydrogen bubbles are formed at the counter electrode (or vice
versa). The challenge is to find materials that combine good visible light absorption
with a high stability against photocorrosion. Moreover, charge carriers should easily
move through the bulk of the material, and the surface of the material should have a
catalytic activity for water splitting. Last but not least, the material and the necessary
processing steps should be cheap.
Despite several decades of research, no material has yet been found that fulfills all
these requirements. We aim to solve this by combining two or more semiconducting
materials in a multi-layer composite which allows us to optimize each individual part.
Within this project, we focus our efforts on Fe2O3 and BiMOx semiconductors. These
materials absorb visible light and are stable against photocorrosion over wide pH
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range. Poor charge transport and poor catalytic activity are the main challenges,
which we aim to address by introducing suitable dopants.
Current research is focused on the synthesis and characterization of BiMOx
photoanode and photocathode materials. In addition, tandem-type heterojunctions
of Fe2O3 with another n-type semiconductors are being studied with the aim to split
water without the need for an additional bias voltage.
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