Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers put a new spin on molecular oxygen

17.07.2019

A multinational team led by researchers from Osaka University use experimental Kelvin probe force spectroscopy to alter the charge states on single oxygen atoms and achieve reversible conversion of oxygen atoms to molecular oxygen

While pinning down a single oxygen atom sounds difficult, trying to then manipulate electrons associated with that single atom to alter its charge sounds downright impossible. However, for the first time, this achievement has been reported by an international research team led by Osaka University.


(a−c) AFM images before (a) and after (b) KPFS manipulation of Oad2−−Oad2− with the tip positioned symmetrically in the middle and the corresponding line profiles (c). The double bright spot became a single one, indicating formation of an oxygen molecular species, O22−. (d−f) AFM images before (d) and after (e) KPFS manipulation of Oad2−−Oad2− with the tip positioned slightly off the middle position between the two atoms and the corresponding line profiles (f). (g−i) AFM images before (g) and after (h) KPFS manipulation of Oad2−−Oad2− with the tip positioned above one oxygen atom and the corresponding line profiles (i), indicating a change in the charge state from Oad2− to Oad − of only the oxygen atom that is under the tip. (j−m) DFT optimized structures are shown in each case: (j) Oad2−−Oad2−; (k) Oad2−−Oad−; (l) Oad−−Oad−; and (m) O22− adsorbed at the on-top Ti5c site. Note that there is also another adsorption site, the bridge site, see SI, section S9. Dashed horizontal lines depict the differences in heights of the oxygen adatoms. (A), (B), and (C) denote the three key manipulation scenarios, see text.

Credit: Osaka University

Along with collaborators from Slovakia and the United Kingdom, graduate student Yuuki Adachi from Osaka University's Department of Applied Physics has recently published this research in ACS Nano.

Oxygen is one of the most abundant elements on Earth. Usually found in its diatomic form, O2, oxygen is highly reactive and doesn't hang around long in a gaseous state. The ground state, or least reactive form of oxygen, is referred to as triplet oxygen because it has three possible arrangements of electron spins.

However, singlet oxygen, with its one possible spin arrangement, is more reactive and plays a major role in a diverse range of chemical reactions, ranging from green fuel production to photodynamic cancer treatments.

Unsurprisingly then, there is significant interest in controlling the formation and activation of molecular oxygen.

"We used Kelvin probe force spectroscopy to examine the charge states of oxygen atoms attached to a titanium dioxide rutile surface, and to then manipulate the charge through the transfer of individual electrons to and from pairs of oxygen atoms," explains Adachi.

"We identified three different charge states amongst the pairs: O-/O-, O2-/O2-, and O-/O2-. Depending on the applied voltage and where we positioned the tip of the probe relative to the atoms, we could then reversibly switch the charge between the O- and O2- states."

The team then showed that they could use the same method to induce controlled, reversible bond formation between two adjacent oxygen atoms, forming molecular oxygen (O2).

Interestingly, they also found that the charge state could be controlled remotely by locating the tip elsewhere on the rutile surface. Electrons were transferred to the oxygen atoms via surface polarons, a phenomenon where electrons can travel through a crystal lattice.

"This level of control over the charge state of oxygen atoms has not previously been possible," says corresponding author of the study Associate Professor Yan Jun Li. "Our work provides a novel method to examine transition-metal-oxide-based catalytic reactions, and can likely be applied to other atoms, and perhaps other surfaces, where controlled chemical reactions initiated by charge manipulation are performed."

###

The article, "Tip-induced control of charge and molecular bonding of oxygen atoms on the rutile TiO2 (110) surface with atomic force microscopy," was published in ACS Nano at DOI: 10.1021/acsnano.9b01792

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and now has expanded to one of Japan's leading comprehensive universities. The University has now embarked on open research revolution from a position as Japan's most innovative university and among the most innovative institutions in the world according to Reuters 2015 Top 100 Innovative Universities and the Nature Index Innovation 2017. The university's ability to innovate from the stage of fundamental research through the creation of useful technology with economic impact stems from its broad disciplinary spectrum.

Website: https://resou.osaka-u.ac.jp/en/top

Saori Obayashi | EurekAlert!
Further information:
https://resou.osaka-u.ac.jp/en/research/2019/20190716_e
http://dx.doi.org/10.1021/acsnano.9b01792

More articles from Physics and Astronomy:

nachricht Newfound superconductor material could be the 'silicon of quantum computers'
16.08.2019 | National Institute of Standards and Technology (NIST)

nachricht Moon glows brighter than sun in images from NASA's Fermi
16.08.2019 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: A miniature stretchable pump for the next generation of soft robots

Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.

Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...

Im Focus: Vehicle Emissions: New sensor technology to improve air quality in cities

Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.

Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...

Im Focus: Self healing robots that "feel pain"

Over the next three years, researchers from the Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris) and Empa will be working together with the Dutch Polymer manufacturer SupraPolix on the next generation of robots: (soft) robots that ‘feel pain’ and heal themselves. The partners can count on 3 million Euro in support from the European Commission.

Soon robots will not only be found in factories and laboratories, but will be assisting us in our immediate environment. They will help us in the household, to...

Im Focus: Scientists create the world's thinnest gold

Scientists at the University of Leeds have created a new form of gold which is just two atoms thick - the thinnest unsupported gold ever created.

The researchers measured the thickness of the gold to be 0.47 nanometres - that is one million times thinner than a human finger nail. The material is regarded...

Im Focus: Study on attosecond timescale casts new light on electron dynamics in transition metals

An international team of scientists involving the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) in Hamburg has unraveled the light-induced electron-localization dynamics in transition metals at the attosecond timescale. The team investigated for the first time the many-body electron dynamics in transition metals before thermalization sets in. Their work has now appeared in Nature Physics.

The researchers from ETH Zurich (Switzerland), the MPSD (Germany), the Center for Computational Sciences of University of Tsukuba (Japan) and the Center for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The power of thought – the key to success: CYBATHLON BCI Series 2019

16.08.2019 | Event News

4th Hybrid Materials and Structures 2020 28 - 29 April 2020, Karlsruhe, Germany

14.08.2019 | Event News

What will the digital city of the future look like? City Science Summit on 1st and 2nd October 2019 in Hamburg

12.08.2019 | Event News

 
Latest News

Working out why plants get sick

16.08.2019 | Life Sciences

Newfound superconductor material could be the 'silicon of quantum computers'

16.08.2019 | Physics and Astronomy

Stanford develops wireless sensors that stick to the skin to track our health

16.08.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>