Nav: Home

Driving chemical reactions with light

May 06, 2019

How can chemical reactions be triggered by light, following the example of photosynthesis in nature? This process is still poorly understood. However, researchers from Johannes Gutenberg University Mainz (JGU) in Germany und Rice University in Houston, USA, have now uncovered a major piece of the puzzle. Their findings have been published recently in Science Advances.

Trees, bushes and other plants are extremely efficient in converting water and carbon dioxide into oxygen and glucose, a type of sugar, by means of photosynthesis. If we can discover the fundamental physical mechanisms involved and harness them for other general applications, the benefits for mankind could be huge. The energy of sunlight, for example, could be used to generate hydrogen from water as a fuel for automobiles. The technique of utilizing light-driven processes like those involved in photosynthesis in chemical reactions is called photocatalysis.

Plasmons: electrons oscillating in synchrony

Scientists commonly use metallic nanoparticles to capture and harness light for chemical processes. Exposing nanoparticles to light in photocatalysis causes so-called plasmons to be formed. These plasmons are collective oscillations of free electrons in the material. "Plasmons act like antennas for visible light," explained Professor Carsten Sönnichsen of Mainz University. However, the physical processes involved in photocatalysis involving such nano-antennas have yet to be grasped in detail. The teams at JGU and Rice University have now managed to shed some light on this enigma. Graduate student Benjamin Förster and his supervisor Carsten Sönnichsen have been investigating this process more extensively.

Modifying plasmon resonances

Förster primarily concentrated on determining how illuminated plasmons reflect light and at what intensity. His technique employed two very particular thiol isomers, molecules whose structures are arranged as a cage of carbon atoms. Within the cage-like structure of the molecules are two boron atoms. By altering the positions of the boron atoms in the two isomers, the researchers were able to vary the dipole moments, in other words, the spatial charge separation over the cages. This led to an interesting discovery: If they applied the two types of cages to the surface of metal nanoparticles and excited plasmons using light, the plasmons reflected different amounts of light depending on which cage was currently on the surface. In short, the chemical nature of the molecules located on the surface of gold nanoparticles influenced the local resonance of the plasmons because the molecules also alter the electronic structure of the gold nanoparticles.

Teamwork crucial for results

Cooperation was essential in the project. "We would never have been able to achieve our results single-handedly," said Sönnichsen. Benjamin Förster spent a year funded by the Graduate School of Excellence Materials Science in Mainz (MAINZ) researching at Rice University in Houston with Professor Stephan Link, who has been visiting professor at MAINZ since 2014. Although the funding of the MAINZ Graduate School provided by the German federal and state governments' Excellence Initiative will be ending in October 2019, Mainz University will - in special cases - continue to provide postgraduates with financial support for this kind of long-term stays abroad. This will be organized under the auspices of the Max Planck Graduate Center (MPGC) and in cooperation with the state of Rhineland-Palatinate.
Related links: - Graduate School of Excellence Materials Science in Mainz (MAINZ) ; - MAINZ Visiting Professor Stephan Link ; - press release "Chemists develop innovative nano-sensors for multiple proteins" (31 July 2013)

Johannes Gutenberg Universitaet Mainz

Related Photosynthesis Articles:

Even bacteria need their space: Squished cells may shut down photosynthesis
Introverts take heart: When cells, like some people, get too squished, they can go into defense mode, even shutting down photosynthesis.
Marine cyanobacteria do not survive solely on photosynthesis
The University of Cordoba published a study in a journal from the Nature group that supports the idea that marine cyanobacteria also incorporate organic compounds from the environment.
Photosynthesis -- living laboratories
Ludwig-Maximilians-Universitaet (LMU) in Munich biologists Marcel Dann and Dario Leister have demonstrated for the first time that cyanobacteria and plants employ similar mechanisms and key proteins to regulate cyclic electron flow during photosynthesis.
Photosynthesis seen in a new light by rapid X-ray pulses
In a new study, led by Petra Fromme and Nadia Zatsepin at the Biodesign Center for Applied Structural Discovery, the School of Molecular Sciences and the Department of Physics at ASU, researchers investigated the structure of Photosystem I (PSI) with ultrashort X-ray pulses at the European X-ray Free Electron Laser (EuXFEL), located in Hamburg, Germany.
Photosynthesis olympics: can the best wheat varieties be even better?
Scientists have put elite wheat varieties through a sort of 'Photosynthesis Olympics' to find which varieties have the best performing photosynthesis.
Strange bacteria hint at ancient origin of photosynthesis
Structures inside rare bacteria are similar to those that power photosynthesis in plants today, suggesting the process is older than assumed.
Just how much does enhancing photosynthesis improve crop yield?
In the next two decades, crop yields need to increase dramatically to feed the growing global population.
Algal library lends insights into genes for photosynthesis
To identify genes involved in photosynthesis, researchers built a library containing thousands of single-celled algae, each with a different gene mutation.
New molecular blueprint advances our understanding of photosynthesis
Researchers at Lawrence Berkeley National Laboratory have used one of the most advanced microscopes in the world to reveal the structure of a large protein complex crucial to photosynthesis, the process by which plants convert sunlight into cellular energy.
Structure and function of photosynthesis protein explained in detail
An international team of researchers has solved the structure and elucidated the function of photosynthetic complex I.
More Photosynthesis News and Photosynthesis Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at