An interdisciplinary collaboration between researchers at Case Western Reserve University and the University of Notre Dame has revealed a critical interaction that is occurring at this plasma-liquid interface in that the electrons in plasma actually serve to separate water, producing hydrogen gas.
In a paper set to appear as a Fast Track Communication in the Journal of Physics D: Applied Physics, David B. Go, assistant professor of aerospace and mechanical engineering at the University of Notre Dame, and his graduate student Paul Rumbach teamed with R. Mohan Sankaran, associate professor of chemical engineering at Case Western Reserve, and his undergraduate student Megan Witzke describe a series of experiments that revealed this new chemistry.
A plasma is an ionized gas, consisting of not only neutral gas molecules but also free electrons and charged ions. Though often thought of as very hot, microplasmas are a unique regime of plasmas that can be formed at atmospheric pressure and are considered "cold plasmas" because they are typically around room temperature. In most plasma-liquid studies, the focus has been on how the different gas species and photons (light) produced by the plasma interact with the liquid.
"Many researchers have revealed that reactive oxygen and nitrogen species in the plasma play an important role in the plasma-liquid interaction," Sankaran said, "But we've always thought that the electrons must be playing an important part. We had preliminary evidence that suggested that the plasma electrons would reduce various chemical species in the liquid but always believed that they must have been interacting with water as well. This study conclusively proves that the electrons directly interact with and electrolyze water."
Water electrolysis is the splitting of water into oxygen and hydrogen and usually occurs in an electrochemical cell with two metals electrodes. In their work Go and Sankaran replaced one of the metal electrodes with an atmospheric-pressure plasma jet. However, the result was that the plasma electrochemical cell acted like a traditional electrochemical cell.
"We found that at the plasma-liquid interface, the plasma formed a virtual cathode and electrons from the plasma reduced hydrogen ions to produce hydrogen gas while at the metal anode, oxidation formed oxygen gas. The reactions are the same as for a traditional electrochemical cell, except now the plasma jet plays the role of one of the electrodes," Go said.
While Go and Sankaran acknowledge that the plasma-liquid interaction is an incredibly complex phenomenon, they agree that this work fills in a crucial piece of the puzzle."As we continue to develop plasma jets for all kinds of applications, be they medical, environmental or for synthesizing materials," Go said. "It's crucial that we understand the fundamental chemistry that is occurring. The role of electrons has been somewhat overlooked, but we show that they play an important role and must be considered as we continue to try to understand these new microplasma devices."
David Go | EurekAlert!
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
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...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy