persistent controversy in catalysts for fuel cells has just been solved by a team of researchers from the Faculty of Pure and Applied Sciences at the University of Tsukuba.
The oxygen reduction reaction is a key step in the operation of fuel cells, but depends on expensive precious metal-based catalysts. Carbon-based catalysts with added nitrogen are among the most promising alternatives to precious metals, and could allow more widespread use of fuel cell technology. However, until now, the arrangement of nitrogen and carbon that gave the catalytic effect remained a mystery, stalling efforts to develop more effective materials.
In an article published this week in Science, a team of researchers from the University of Tsukuba identified the catalytic structure and proposed a mechanism by which the reaction works. "We knew that nitrogen-doped carbon was a good oxygen reduction catalyst, but no one was sure whether the nitrogen was pyridinic or graphitic," said corresponding author Prof. Junji Nakamura.
To solve the mystery, the team fabricated four model catalyst substrates, which simulated competing potential structures and analyzed their reaction performance. Pyridinic nitrogen, or nitrogen atoms bonded to two carbon atoms, occur mainly at the edges of the material. By patterning the substrates to change the number of edges, the team could control the presence of pyridinic nitrogen and measure how it affected the catalytic performance. These results showed that the active catalytic sites were associated with pyridinic nitrogen.
Taking the research a step further, the investigators then proposed the various stages of the reaction mechanism after finding that it was actually the carbon atom next to the nitrogen that was the active site rather than the nitrogen atom itself. As the corresponding author Prof. Nakamura noted: "Clarifying the active site and mechanism is a great step forward and will allow optimization studies to focus on driving up catalyst performance."
Masataka Watanabe | EurekAlert!
Reliable molecular toggle switch developed
30.03.2017 | Karlsruher Institut für Technologie (KIT)
Researchers shoot for success with simulations of laser pulse-material interactions
29.03.2017 | DOE/Oak Ridge National Laboratory
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering