Nav: Home

Iodide salts stabilise biocatalysts for fuel cells

February 14, 2020

Contrary to theoretical predictions, oxygen inactivates biocatalysts for energy conversion within a short time, even under a protective film. A research team of the Resolv Cluster of Excellence at Ruhr Universität Bochum (RUB) has found out why: Hydrogen peroxide forms on the protective film. The addition of iodide salts to the electrolyte can prevent this from happening and considerably extend the life of the catalysts. The team around Professor Nicolas Plumeré from Resolv, Dr. Erik Freier from the Leibniz Institute for Analytical Sciences Dortmund and Professor Wolfgang Lubitz from the Max Planck Institute for Chemical Energy Conversion in Mülheim reports its findings in Nature Communications of 14 February 2020.

Deactivated within seconds

Biological and bio-inspired catalysts are available in abundance and their catalytic performance is close to that of precious metal catalysts. Nevertheless, they are not widely used for energy conversion processes. The reason for this is their instability. "Some of the most active small molecule conversion catalysts relevant to sustainable energy systems are so sensitive to oxygen that they are completely deactivated within seconds when they come into contact with it", explains Nicolas Plumeré.

Infinite protection - so far only in theory

The research group had recently discovered that redox-active films can protect bio-inspired and even biocatalysts such as hydrogenases against this. Theoretical models predict that protection against oxygen should last indefinitely. In experiments, however, this protection has so far only been effective for a few hours. "This contradicts our theoretical calculations and cannot be explained, even in view of the lifetime of the same catalyst in an oxygen-free environment", says Plumeré. The latter is up to six weeks with constant turnover.

Combination of methods explores the problem

This led the researchers to conclude that either the mechanism for protection against oxygen is not yet understood, or that apart from deactivation by oxygen, additional harmful processes take place. To investigate this, they combined various methods that allowed them to examine what happens in the protected layer in detail. The combination of confocal fluorescence microscopy and coherent anti-Stokes Raman scattering performed in the laboratory by Erik Freier, with electrochemistry for the analysis of the protective matrix showed: The protective process leads to an accumulation of hydrogen peroxide, which promotes damage to the catalytic film.

Suppressing hydrogen peroxide formation

We show that the decomposition of hydrogen peroxide with iodide salts increases the half-life of a hydrogenase for hydrogen oxidation to up to one week at constant turnover, even with constant exposure to high oxygen concentrations. "Overall, our data confirm the theory that redox films make oxygen-sensitive catalysts completely immune to direct deactivation by oxygen", concludes Plumeré. "However, it is very important to also suppress hydrogen peroxide production in order to achieve complete protection against oxidative stress."

"Our work shows that the simple strategy of adding iodide salts to the electrolyte can be sufficient to significantly reduce the inactivation rates of biocatalysts", the researchers say. They believe that this will enable the widespread implementation of other electrocatalytic processes in real applications. This also includes energy conversion processes such as solar fuel generation by carbon dioxide reduction and the electrosynthesis of fine or basic chemicals such as ammonia.
-end-
Funding

The work was funded by the German Research Foundation within the framework of the Ruhr Explores Solvation Resolv Cluster of Excellence (EXC-2033 - project number 390677874) and the Shields project (PL 746/2-1) and by the European Research Council within the framework of Starting Grant 715900. Further support was provided by the Max Planck Society, the China Scholarship Council as well as the Ministry of Culture and Science of the State of North Rhine-Westphalia, the Governing Mayor of Berlin - including science and research, and the Federal Ministry of Education and Research as well as the Leibniz Research Cluster (031A360E).

Original publication

Huaiguang Li, Ute Münchberg, Alaa A. Oughli, Darren Buesen, Wolfgang Lubitz, Erik Freier, Nicolas Plumeré: Suppressing hydrogen peroxide generation to achieve oxygen-insensitivity of a [NiFe] hydrogenase in redox active films, in: Nature Communications, 2020, DOI: 10.1038/s41467-020-14673-7

Press contact

Prof. Dr. Nicolas Plumeré
Molecular Nanostructures Research Group
Faculty of Chemistry and Biochemistry
Ruhr-Universität Bochum
Germany
Phone: +49 234 32 29434
Email: nicolas.plumere@rub.de

Ruhr-University Bochum

Related Hydrogen Articles:

Hydrogen energy at the root of life
A team of international researchers in Germany, France and Japan is making progress on answering the question of the origin of life.
Hydrogen alarm for remote hydrogen leak detection
Tomsk Polytechnic University jointly with the University of Chemistry and Technology of Prague proposed new sensors based on widely available optical fiber to ensure accurate detection of hydrogen molecules in the air.
Preparing for the hydrogen economy
In a world first, University of Sydney researchers have found evidence of how hydrogen causes embrittlement of steels.
Hydrogen boride nanosheets: A promising material for hydrogen carrier
Researchers at Tokyo Institute of Technology, University of Tsukuba, and colleagues in Japan report a promising hydrogen carrier in the form of hydrogen boride nanosheets.
World's fastest hydrogen sensor could pave the way for clean hydrogen energy
Hydrogen is a clean and renewable energy carrier that can power vehicles, with water as the only emission.
Chemical hydrogen storage system
Hydrogen is a highly attractive, but also highly explosive energy carrier, which requires safe, lightweight and cheap storage as well as transportation systems.
Observing hydrogen's effects in metal
Microscopy technique could help researchers design safer reactor vessels or hydrogen storage tanks.
The 'Batman' in hydrogen fuel cells
In a study published in Nature on Jan. 31, researchers at the University of Science and Technology of China (USTC) report advances in the development of hydrogen fuel cells that could increase its application in vehicles, especially in extreme temperatures like cold winters.
Paving the way for more efficient hydrogen cars
Hydrogen-powered vehicles emit only water vapor from their tailpipes, offering a cleaner alternative to fossil-fuel-based transportation.
New catalyst produces cheap hydrogen
QUT chemistry researchers have discovered cheaper and more efficient materials for producing hydrogen for the storage of renewable energy that could replace current water-splitting catalysts.
More Hydrogen News and Hydrogen 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

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
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

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.