Solar fuel photocatalysis mechanism mapped

05 Sep 2012

New measuring technique 'brings closer' improvements in solar fuel development.

Detailed molecular-scale measurements of a chemical reaction accelerated by sunlight have been made for the first time ever. Chemists at Utrecht University, Netherlands, and the Friedrich Schiller University Jena, Germany, have set up a special microscope to simultaneously take part in and observe the catalysed chemical reaction.

The results have been published in the journal Nature Nanotechnology on 18 August 2012. Professor Bert Weckhuysen from Utrecht University said of this research: "Now we can focus on making solar fuels more profitable."

Certain chemical reactions can be accelerated by sunlight and by contact with catalysts. These photocatalytic reactions can now be monitored on a molecular level thanks to a new measuring technique developed by Utrecht chemists Professor Bert Weckhuysen, PhD student Evelien van Schrojenstein Lantman and Dr. Arjan Mank, and scientists from Jena University Professor Volker Deckert, who works also at the Institute of Photonic Technology in Jena, Germany, and Dr. Tanja Deckert-Gaudig.

Solar fuel

The investigators have stated that research may offer new opportunities for the improvement of so-called solar fuels. This sustainable form of fuel stores solar energy in molecules, comparable to photosynthesis in plants.

"Solar fuels are not currently profitable, because we do not know how to produce the fuel efficiently", said Weckhuysen. "Our new measuring technique makes it possible to see exactly what happens during the production of solar fuels, which will enable us to come up with improvements in the future."

In this study, researchers made ingenious use of a sharp needle with a "tip-enhanced Raman microscope", which makes recordings just above the reaction surface. Deckert said: "The key factor is the silver particle at the tip apex that acts as detection system and as a catalyst with nanometer dimension at the same time.

He added, "This enables us to investigate the reaction with unprecedented spatial resolution and sensitivity. Investigation of other catalytic systems should be straight forward."

The research is funded by NanoNextNL, the Netherlands Research School Combination-Catalysis (NRSC-C) and NWO. The research team comprises 
Evelien M. van Schrojenstein Lantman, Tanja Deckert-Gaudig, Arjan J.G. Mank, Volker Decker, Bert M. Weckhuysen.

Their article Catalytic processes monitored at the nanoscale with tip-enhanced Raman spectroscopy is published in Nature Nanotechnology, 2012, DOI: 10.1038/NNANO.2012.131. For further information, contact:
 Professor Dr. Volker Deckert
Institute of Physical Chemistry of Jena University
, Tel: +49 3641 948347 
Email: volker.deckert@uni-jena.de

About the Author

Matthew Peach is a contributing editor to optics.org