Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Inspired by a Breakwater

18.12.2012
Highly efficient electrocatalyst for the reduction of oxygen in fuel cells and batteries

Be it a battery or a fuel cell, efficient electrodes are the be-all and end-all of every electrochemical cell. In the journal Angewandte Chemie, a team of Korean and American scientists has now introduced a novel material for electrodes based on affordable melamine foam and carbon black.



The high porosity significantly facilitates fast mass transport and a high number of catalytically active centers drastically increase the oxygen-reducing activity of cathodes for fuel cells and metal-air batteries.

The reaction that occurs at the cathodes of fuel cells and metal-air batteries is the electrochemical reduction of oxygen, namely the oxygen reduction reaction (ORR). This reaction is considerably inhibited because of its sluggish rate, and the efficiency of the cells is lower than it could be. The catalytic cathode must ensure that oxygen reacts with water, taking up electrons to form OH- ions in alkaline solution. The problem is that in a complex system involving solid, liquid, and gaseous reactants, transport processes are often too slow and inhibit the process, especially when discharging with higher current densities.

Cathodes made of a porous carbon support (carbon black) on which a catalytically active metal like platinum is finely dispersed can very effectively minimize this kinetic inhibition. However, they are expensive and not very stable, thus making them impractical for widespread application. A team led by Jaephil Cho at the Ulsan National Institute of Science and Technology (Korea) and Meilin Liu at the Georgia Institute of Technology (USA) thus aimed to develop a more economical alternative.

They were inspired by the tetrapod structure (Greek tetra: four, podes: feet) of breakwaters to synthesize a new highly efficient electrocatalyst. Tetrapods, whose four “feet” are pointed toward the corners of an imaginary tetrahedron, are constructed at the coast as well as near dams and piers to reduce the force of waves crashing against the shore. These structures also provide sanctuary for marine life forms in their many large cavities. When melamine foam is pyrolyzed and ground with a mortar and pestle, it forms microscopic fragments resembling tetrapods.

The scientists treated melamine foam with iron chloride and nitrogen-doped ketjenblack (conducting pellets of carbon black). They carbonized this product and extracted it with sulfuric acid. The resulting nanotetrapods studded with nanoparticles of carbon black have a very high specific surface area, a large number of catalytically active centers (Fe/Fe3C, and CN groups), and many pores that allow for rapid mass transport. Cathodes made of this new electrode material are highly durable and excellent performance, comparable to those of metal-based cathodes – at a much lower price. These may represent a highly promising starting point for a new generation of inexpensive and highly efficient metal-air batteries and fuel cells.

About the Author
Jaephil Cho is Professor and Dean at the Interdisciplinary School of Green Energy at UNIST (South Korea). He is Director of the Converging Research Center for Innovative Battery Technologies and of the IT Research Center (both supported by the Korean government). His current research is focused mainly on metal–air batteries and nanostructured electroactive materials for lithium-ion batteries.
Author: Jaephil Cho, Ulsan National Institute of Science and Technology (Rep. Korea), http://jpcho.com/
Title: A Highly Efficient Electrocatalyst for the Oxygen Reduction Reaction: N-Doped Ketjenblack Incorporated into Fe/Fe3C-Functionalized Melamine Foam

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201207193

Jaephil Cho | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>