Detailed molecular-scale measurements of a chemical reaction accelerated by sunlight have been made for the first time ever. Chemists at Utrecht University have set up a special microscope to simultaneously take part in and observe the catalysed chemical reaction. The results were published on 19 August in the prestigious journal Nature Nanotechnology. Professor Bert Weckhuysen said of this research: "Now we can focus on making solar fuels more profitable."
Some 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, Evelien van Schrojenstein Lantman and Arjan Mank, who collaborated with German colleagues on this project.
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 clever use of a sharp needle with a tip-enhanced Raman microscope, which makes recordings just above the reaction surface. Weckhuysen said: "When combined with visible laser light, the layer of silver on the needle functions as a catalyst. So, the adapted microscope becomes a part of the chemical reaction and is able to follow the reacting molecules in great detail."
Catalytic processes monitored at the nanoscale with tip-enhanced Raman spectroscopy, Evelien M. van Schrojenstein Lantman, Tanja Deckert-Gaudig, Arjan J.G. Mank, Volker Decker, Bert M. Weckhuysen, Nature Nanotechnology, 2012.
This research is funded by NanoNextNL, the Netherlands Research School Combination–Catalysis (NRSC-C) and NWO.
Monica van der Garde, Press Officer, Utrecht University, Faculty of Science, +31 6 51 97 02 83, M.vanderGarde@uu.nl.