Aarhus Universitets segl

Research

Nanomaterials have very strongly entangled synthesis-structure-properties relationships. Our research is balanced between synthesis, characterization and applications of nanomaterials and in particular precious metal nanoparticles. Our expertise is in developing simpler synthesis focusing on as few chemicals as possible and as benign chemicals as possible. This leads to more active nanomaterials. Ultimately we aim to move towards nanomaterial recycling.

Synthesis

We aim to develop simpler nanomaterial syntheses, understand how nanomaterials form and which parameters are key to control the resulting size, shape, composition, etc. This knowledge will help us to develop increasingly complex nanomaterials with new and exciting properties.
Our interest in this direction is going towards bi- and multi- metallic nanomaterials: to reduce the amount of precious metals and tune the shape, structure and properties of nanomaterials.

Characterization

Characterization is a must to understand how nanoparticles form and/or evolve during operating conditions, e.g. as catalysts. This brings useful knowledge to tune the properties of the nanomaterials and/or propose mitigation strategies to optimize their synthesis but also their lifetime in real-life conditions. We use a range of characterization such as UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and more advanced techniques like small angle X-ray scattering (SAXS), X-ray total scattering with pair distribution function analysis (PDF), X-ray absorption spectroscopy (XAS), etc., in house or via collaborations, e.g. at synchrotron facilities. The fun starts when different techniques can be combined to learn more about the nanoscale.

Our interest in this direction is to understand better how surfactant-free nanomaterials are formed and stabilized, moving towards a deeper understanding of the nanomaterial formation at the chemical and structural levels. This knowledge will ultimately be key to understand their properties.

Catalysis

Precious metal nanomaterials are relevant for almost any type of catalysis. Precious metal nanoparticles are typically supported on another material and in recent years colloidal precious metal nanoparticles have shown to be ideal system to perform fundamental catalytic studies. We believe that our surfactant-free colloidal approach will help to bridge the gap academia-industry. Surfactant-free nanoparticles are more simply functionalized to develop hybrid homogeneous-heterogeneous catalysts. Surfactant-free nanoparticles are often more active than the state-of-the-art. While proof of concepts have been made in particular for electro-catalytic applications, it is now time to explore further these features for more systems, e.g. photocatalysis, energy conversion and electrocatalysis at broad (e.g. oxygen evolution reaction ORR, oxygen evolution reaction OER, and possibly ultimately CO2 reduction reaction CO2RR or nitrogen reduction reaction NRR) or small organic molecules oxidations  (e.g. methanol oxidation reaction MOR, ethanol oxidation reaction EOR or formic acid oxidation FAO), or liquid and gad phase heterogeneous catalysis all the way to polymer recycling and sensing or water remediation.

Re/Up-cycling

Since precious metals are critical raw materials their re/up-cycling is key. This can be achieved by developing stable materials that do not degrade over time, materials than can be re-used several times, and/or developing ways to recover the precious metals. For instance, converting nanomaterials back to molecular complexes that can then be used to re-synthesize nanomaterials would be an important achievement. Although we have little expertise in this area yet, we are very much looking forward to look into it in the future.


Find out more here: http://nestresearchlab.com/