The researchers have published their findings, “Dynamics of Porphyrin Electron-Transfer Reactions at the Electrode–Electrolyte Interface at the Molecular Level,” in the international scientific journal, Angewandte Chemie (http://www3.interscience.wiley.com/cgi-bin/abstract/114287533/ABSTRACT).
“The simplest chemical reactions are oxidation and reduction,” says Eric Borguet, professor of chemistry at Temple and the study’s main author. “Chemistry is basically all about the transfer of electrons from one atom to another or one molecule to another. Those reactions are called ‘redox’ reactions.”
According to Borguet, one important place where these reactions occur is on an electrode surface. For example, metal corrosion is essentially oxidation. Corrosion can sometimes be reversed by reducing the oxides and reclaiming the metal.
“Most of our studies of oxidation and reduction basically involve measuring the flow of electrons in and out of bulk chemical systems,” he says. “We’ve never really looked at this at the single molecule level, looking at it one molecule at a time. And it wasn’t necessarily clear that we could do that.”
As part of their research, Borguet and his collaborator were looking on a metal electrode surface at porphyrins, an important class of molecules that are involved in a number of biological processes, and in fact, can act as a catalyst for these processes.
The Temple researchers used scanning tunneling microscopy, in which a sharp metal tip scans the electrode surface and measures the passage of electrons from the tip, through the molecules, to the metal surface. They noted that the chemical state of the molecule changes the ability of the electrons to pass from the metal tip to the electrode.
“We noticed that some of these molecules, under certain conditions, appeared dark while others appeared bright,” noted Borguet. “What we essentially figured out was that the molecules change color and appear dark when we apply a potential to the electrode that begins to oxidize, or essentially pull out an electron from, the molecule. So now it seems that we can see the difference between oxidized molecules—the dark ones—and reduced molecules—the bright ones.”
Borguet says that by gaining a handle on the molecules’ chemical state, researchers now have the ability to identify oxidized and reduced molecules, and to track them individually.
“As researchers, we can now ask questions such as ‘Do molecules oxidize one at a time or do entire domains or areas on the surface oxidize together"’,” he says. “Do they oxidize in pairs or in clusters" If one molecule oxidizes, is it going to make the oxidation of a neighboring molecule more or less likely" What is the timescale under which these processes occur and what factors facilitate redox reactions"”
Borguet believes the Temple researchers are the first to observe and understand this interfacial electron transfer process at the single molecule level.
“We think if you look back in the literature and at other peoples’ data there is some evidence for this, but I don’t think they actually recognized that they were observing this process,” he says.
Preston M. Moretz | EurekAlert!
Atomic-level motion may drive bacteria's ability to evade immune system defenses
24.04.2017 | Indiana University
Two-dimensional melting of hard spheres experimentally unravelled after 60 years
24.04.2017 | University of Oxford
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences