Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Testing predictions in electrochemical nanosystems

07.06.2010
From theoretical insights to the lab bench

Physicists at the Technische Universitaet Muenchen (TUM) are gearing up for experimental tests of findings they arrived at through theoretical considerations: that electrochemical reactions take place more rapidly on isolated, nanometer-scale electrodes than on their familiar macroscopic counterparts, and that this surprising behavior is caused by thermal noise.

Prof. Katharina Krischer and Dr. Vladimir Garcia-Morales published their results earlier this year in the Proceedings of the National Academy of Sciences (PNAS). The project is supported by the TUM Institute for Advanced Study, which emphasizes scientifically "risky" research that may have potential for creating new fields of technology.

Familiar processes take unfamiliar turns when they're observed on the nanoscale, where models that accurately describe macroscopic phenomena may not be reliable, or even applicable. Electrochemical reactions, for example, which normally appear to proceed smoothly, seem to halt and stumble in the nanoworld. When the electrodes involved are less than ten nanometers wide, chance plays a bigger role: Random movement of molecules makes the exact timing of reactions unpredictable.

Now, however, just such a process can be described by a theoretical model developed by the TUM physicists. They demonstrated their method in a study of nanoscale reactions, published in PNAS, which presented a new electrochemical "master equation" underlying the model. Their results show that thermal noise -- that is, the randomness of molecular movement and individual electron-transfer reactions -- actually plays a constructive role in a nanoscale electrochemical system, enhancing reaction rates.

"The effect predicted is robust," says Dr. Vladimir Garcia-Morales, recently named a Carl von Linde Junior Fellow of the TUM Institute for Advanced Study, "and it should show up in many experimental situations." To see for themselves, the researchers have turned their attention from the chalkboard and the computer to the lab bench. Their experiments present several technical challenges. One is not only to fabricate disk-shaped electrodes with a radius of just three to ten nanometers, but also to determine the electrode area accurately. Another tough requirement is setting up the electronics to minimize noise from external sources, to make sure the influence of internal, molecular noise can be observed.

"An important aspect," Dr. Garcia-Morales says, "is that the reported effect can change our view on the collective properties of many electrodes. Common intuition suggests that if one makes the electrode area ten times as large, the current would be ten times as high. But, as we show with our theory, the proportionality does not hold any more when the electrode dimension becomes as small as a few nanometers."

Experimental validation could also help to transpose the TUM researchers' theory to a variety of situations. They say their method accounts for effects that macroscopic models can't explain and could prove useful in addressing a variety of research questions. "The applicability of the electrochemical master equation is in fact beyond the specific problem addressed in the publication," Prof. Katharina Krischer stresses. "It establishes a general framework for stochastic processes involving electron-transfer reactions. For example, we now use it to predict the quality of electrochemical clocks at the nanoscale."

Support for this research has come from the European Union (Project DYNAMO), the Nanosystem Initiative Muenchen Cluster of Excellence, and the TUM Institute for Advanced Study.

Original publication:

Fluctuation enhanced electrochemical reaction rates at the nanoscale, Vladimir Garcia-Morales and Katharina Krischer, PNAS 107, 4528� (2010). Doi: 10.1073/pnas.0909240107

Contact:
Prof. Katharina Krischer
Technische Universitaet Muenchen
Department of Physics (E19a)
James-Franck-Str. 1
85748 Garching, Germany
Tel: +49 89 289 12535, Fax: +49 89 289 12338
krischer@ph.tum.de
Technische Universitaet Muenchen (TUM) is one of Europe's leading universities. It has roughly 420 professors, 7,500 academic and non-academic staff (including those at the university hospital "Rechts der Isar"), and 24,000 students. It focuses on the engineering sciences, natural sciences, life sciences, medicine, and economic sciences. After winning numerous awards, it was selected as an "Elite University" in 2006 by the Science Council (Wissenschaftsrat) and the German Research Foundation (DFG). The university's global network includes an outpost in Singapore. TUM is dedicated to the ideal of a top-level research based entrepreneurial university.

Patrick Regan | EurekAlert!
Further information:
http://www.tum.de

More articles from Physics and Astronomy:

nachricht Rapid water formation in diffuse interstellar clouds
25.06.2018 | Max-Planck-Institut für Kernphysik

nachricht When fluid flows almost as fast as light -- with quantum rotation
22.06.2018 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany

25.06.2018 | Ecology, The Environment and Conservation

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>