Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How the first step affects the (watery) result

24.06.2010
German Scientists from Jena and Erlangen-Nürnberg show the way to a more effective creation of hydrogen

Energy from hydrogen – scientists from all over the world work on this solution to overcome the energy crisis. Amongst other things they try to use the sunlight as driving force for the splitting of water into hydrogen and oxygen.

In trying to copy the photosynthesis in the laboratory a team of scientists of the Universities of Jena and Erlangen-Nürnberg and of the Institute of Photonic Technology (IPHT) in Jena (Germany) made a huge step forward. The physiccists and chemists were able to prove in their tests, that the first step already affects the efficiency of hydrogen generation.

“This is as if you would decide about where you´re going to by turning the ignition key in the car,” says PD Dr Michael Schmitt from the Institute of Physical Chemistry (IPC) of the University of Jena. To put it scientifically: “The Franck-Cordon-point has to be created in such a way that the initial process of transferring electrons already points into the direction of the catalytic active centre.“ The results were published in the science journal „Angewandte Chemie Int. Ed.“.

In their tests for a more efficient energy conversion the scientists focus on chemical photo catalysts. With this light is being used to let electrons “jump“ well-directed from one subunit of the molecule to the other or to transport them over a ligand, which is a “bridge“.

Like the photosynthesis this process, which the chemists run in the laboratory, works in two main steps: A special metal complex with Ruthenium as its main component serves as an antenna which harvests the light. The Ruthenium then transfers an electron onto the reaction centre. The core of the reaction centre is a Palladium atom. At this metal centre the hydrogen is finally generated. But other than in nature not all electrons reach the palladium centre from the Ruthenium in the laboratory construction. Some choose “detours“, some enter “roundabouts“ or “blind alleys“ and thus are being lost for the reaction. “Supported by resonance Raman spectroscopy we were able to watch and see where the electron ends after directly after the photoexitation,“ describes Prof Dr Juergen Popp, director of IPC and IPHT. „Thereby we were able to develop a new synthesis paradigm“, Michael Schmitt adds. The team of scientists could prove that the efficiency of hydrogen generation depends on the light wavelength. It is more efficient the redder the light used for photo excitation is – light of a wavelength of 550 nm is ideal. “The redder the light the more electrons are transferred to the ligand, that connects the Ruthenium with the Palladium“, Schmitt says. Moreover the initial absorption step decides where the electron goes and thus how effective the generation of energy is.

“This knowledge enables us to put up well-directed barriers so that the electrons don´t take a ,wrong turn’ but exclusively end up at the Palladium“, says Prof Popp explaining the application potential of this fundamental research. In the laboratory the hydrogen generation is four times above former data but still far below the necessary rate. Now it is up to the chemists, like the participating Prof. Dr Sven Rau, to optimize the molecular catalysts, that “no electrons will be taken on by terminal ligands,“ as Schmitt explains.

The scientists know that it is still a long way to go to copy the photosynthesis of nature correctly and efficiently. “But due to our spectroscopic analysis we took a huge step on this way“, Prof Popp is sure though.

Original Publication:
Stefanie Tschierlei, Michael Karnahl, Martin Presselt, Benjamin Dietzek, Julien Guthmuller, Leticia González, Michael Schmitt, Sven Rau und Jürgen Popp: „Photochemisches Schicksal:„Photochemical Fate: The First Step Determines Efficiency of H2 Formation with a Supramolecular Photocatalyst“, Angew. Chem. Int. Ed. 2010, 122, 3981-3984.
Contact:
Prof. Dr. Jürgen Popp / PD Dr. Michael Schmitt
Institute of Physical Chemistry of Jena University
Helmholtzweg 4
D-07743 Jena
Phone: +049 (0)3641 / 948320 or 948367
Email: juergen.popp[at]uni-jena.de / m.schmitt[at]uni-jena.de

Axel Burchardt | idw
Further information:
http://www.uni-jena.de/en/start_en.html

Further reports about: CHEMISTRY IPC IPHT Palladium Ruthenium hydrogen generation

More articles from Life Sciences:

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

nachricht Transforming plant cells from generalists to specialists
07.12.2016 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>