Models for Heterogeneous Catalysts: Complex Materials at the Atomic Level

Prof.Dr.Hajo Freund (director of the Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin)

Understanding catalysis, and in particular heterogeneous catalysis, has been based on the investigation of model systems. The enormous success of metal single crystal model surface chemistry, pioneered by physical chemists, is an excellent example. Increasing the complexity of the models towards supported nanoparticles, resembling a real disperse metal catalyst, allows one to catch in the model some of the important aspects that cannot be covered by single crystals alone. One of the more important aspects is the oxide-particle interface. We have developed experimental strategies to prepare model systems based on single crystalline oxide films, which are used as supports for metal and oxide nanoparticles, whose geometric structure, morphology, electronic structure, as well as interaction and reaction with molecules from the gas phase may be studied at the atomic level. Such oxide films, in particular those of reduced thickness, show interesting intrinsic catalytic behavior. The thin oxide film approach allows us to prepare and study amorphous silica as well as 2D-zeolites. Those systems, in spite of their complexity, do lend themselves to theoretical modelling as has been demonstrated. We will refer to our collaborating theory groups (J. Sauer/Berlin, G. Pacchioni/Milano, H. Häkkinen/Jyväskylä, M. Scheffler/FHI, Berlin) in the presentation.

Colloids at interfaces : how the rules of the game change…

Prof.Dr. Jan Vermant (extraordinary professor at KU Leuven and professor of Soft Materials at ETH Zürich)

Colloid science and technology has taken up an important place in the scientific community, as well as in our daily lives.  Important contributions from the Debye institute have taught us the importance of making model colloidal particles, with controlled shape, size and architecture, often aimed at assembling them in hierarchical structures. The latter can be achieved by a careful and often gentle control over the colloidal interactions. In the present talk I will give an overview of how many of these aspects change when particles are now pinned down at the interface between two fluids. The rules of the colloid game change drastically, with some interactions being greatly amplified, whereas as some are fundamentally new, such as the lateral capillary forces.  Although when going from 3D to 2D - the game becomes slightly less subtle, novel opportunities arise to create structured interfaces and exploit this in the design of new materials, be it using planar monolayers or in interface dominated systems such as emulsions, foams or phase separating systems. An important role is given to the rheological properties of the interface, and tailoring the interfacial rheology is a key element.

Shining a (bright) light on the very small

Prof.Dr. Romain Quidant (IFCO Institute, Barcelona)

Extensive research in Nano-optics over the last decade has made possible controlling optical fields on the nanometer scale. Such concentration of light, well beyond the limit of diffraction opens plenty of opportunities for enhanced interaction with tiny amounts of matter down to the single molecule/atom level. In this talk we will present our recent advances in enhanced light-matter interaction on the nanometer scale and their applications to both quantum optics and biosciences.

The first part of the talk focuses on the use of plasmonic nanostructures to control the emission properties of single quantum emitters. In particular we discuss our recent efforts in deterministically manipulating individual quantum dots and NV centers in diamond nanocrystals and coupling them with plasmonic nanoantennas and waveguides.

In a second part we present our recent advances in optical nanomanipulation and optomechanics. We first discuss the use of nanoplasmonics to create nano-optical tweezers, capable to trap and 3D- manipulate individual nano-objects with light intensities of laser pointers. We also discuss the use of a nanoparticle optically levitating in vacuum as a novel optomechanical system with unique properties for both weak force sensing and testing quantum mechanics on the mesoscopic scale.

Finally, we focus on the application of nanoplasmonics to biosciences. In particular, we present an integrated lab-on-a-chip platform hosting plasmonic nanoantennas for the detection of low concentrations of biomolecules in complex media.  The platform has been successfully used for multiplexed, fast and sensitive detection of cancer markers in human serum and is currently tested for early cancer diagnosis and treatment monitoring.