#weekendusers Catalysis in a nanoparticle

28-10-2016

How do you study a single nanoparticle in a catalyst as it works? This is the challenge of a team of scientists from DESY who will spend this weekend on ID01, characterising a tiny iridium particle of 100 nanometres in a small catalyst model. The aim: to get insight into structural changes of the surfaces of the nanoparticle during a catalytic reaction. This experiment is part of the Joint Research Activities supported by the European Horizon2020 Nanoscience Foundries and Fine Analysis (NFFA) network.

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It sounds easier than it actually is. The nanoparticle is around 100x 100 nanometres and the beam 300x300 nanometres. “The first challenge is to select the particle in advance”, explains Thomas Keller, main proposer of the experiment. “We did this using a scanning electron microscope at DESY NanoLab”, he explains. The next step is to find it on the beamline. The team uses an Advanced Nano-Object Transfer and Positioning protocol, which is currently being developed within NFFA to allow  for an easy transfer and re-location of selected small objects from different nanoscience instruments to nano-focused X-ray beamlines.

It is the first time that such an experiment will take place using a pre-selected, individual iridium nanoparticle. Until now there have been many experiments in catalysts, also at the nano level, but never just a single iridium nanoparticle. “Normally the beam is so large that you study the whole catalyst and you end up losing information on the way”, says Vedran Vonk, another scientist of the team, “whilst here we are looking at a single nanoparticle, so we are hoping to get more information on the behaviour of this isolated particle”. Specifically, they focus on the behaviour of this nanoparticle and its surface, hopefully revealing shape changes in their catalytic activity while participating in the overall catalytic reaction.

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The team, from left to right, placing the sample on the beamline: Manuel Abuín, Vedran Vonk, Thomas Keller and Kim Young Yong.

ID01 is the ideal beamline for this kind of research: “It provides the required X-ray beam, high brilliance and nano-focusing options”, explains Tobias Schulli, beamline responsible. “ID01 is a dedicated beamline, where significant effort has been taken to make such complex in-situ experiments on single nano-objects possible”, says Andreas Stierle, head of DESY NanoLab. “As one example, a continuous scanning option has been established that permits to quickly search a preselected nanoparticle.”

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Thomas Keller holding the set-up where the sample is kept. 

Research at the nanoscale has taken off in the last decade worldwide, and experiments such as this one will allow methodology to develop. In this context, NFFA-Europe is an open access platform, granted by the EU to carry out projects for research at the nano-scale extending from synthesis to nano-characterisation, to theory and numerical simulation.

Detailed information on the NFFA project with its joint research activities and user access options to perform research on the nanoscale using growth, nano-lithography, nano-characterisation, theory and simulation and fine-analysis with synchrotron, free electron laser and neutron radiation sources is available from the NFFA website at http://www.nffa.eu/

 

 

Text and photos by Montserrat Capellas Espuny

Top image: L-shaped marker written by electron-beam assisted deposition to serve as guide to the iridium nanoparticle that was preselected in the SEM at DESY NanoLab. The marker serves as a test marker for the advanced nano-object transfer and positioning protocol to be developed within NFFA. In this experiment, the users are exploiting the absorption of the substrate Bragg peak within the marker material.