. 24/7 Space News .
The platinum riddle
by Staff Writers
Vienna, Austria (SPX) Apr 05, 2022

The iron oxide surface with two platinum atoms, each of which is attached to a carbon monoxide molecule.

What happens when a cat climbs onto a sunflower? The sunflower is unstable, will quickly bend, and the cat will fall to the ground. However, if the cat only needs a quick boost to catch a bird from there, then the sunflower can act as a "metastable intermediate step". This is essentially the mechanism by which individual atoms of a catalyst capture molecules in order to chemically transform them.

Several years ago, the Vienna University of Technology surface physics group discovered that platinum "single-atom" catalysts could oxidize carbon monoxide at temperatures which, according to their theoretical models, should not have been possible. Now, with the help of atomic-scale microscope images and complex computer simulations, they have been able to show that both the catalyst itself and the material on which it is anchored assume energetically unfavorable "metastable" states for a short time to allow the reaction to happen in a special way. The results have been published in the journal Science Advances.

Single atoms as catalysts
The research group of Prof. Gareth Parkinson at the Institute of Applied Physics at the TU Wien is investigating the smallest catalysts possible: Individual platinum atoms are placed on an iron oxide surface. They then come into contact with carbon monoxide gas and convert into carbon dioxide, like happens in a modern car exhaust.

"This process is technically very important, but exactly what happens when the catalyst is reduced in size to the single atom limit has not been clear until now," says Gareth Parkinson. "In our research group, we study such processes in a number of ways: on the one hand, we use a scanning tunneling microscope to produce extremely high-resolution images on which you can study the movement of individual atoms. And on the other hand, we analyze the reaction process with spectroscopy and computer simulations."

Whether the platinum atoms are active as a catalyst depends on the temperature. In the experiment, the catalyst is heated slowly and evenly until the critical temperature is reached, and carbon monoxide is converted to carbon dioxide. That threshold is about 550 Kelvin. "However, this did not fit our original computer simulations," says Matthias Meier, first author of the current publication. "According to density functional theory, which is normally used for such calculations, the process could only take place at 800 Kelvin. So we knew: Something important had been overlooked here until now."

A metastable state: short-lived, but important
For several years, the team gathered extensive experience with the same materials in other reactions, and as a result, a new picture emerged step by step. "With density functional theory, you normally calculate that state of the system that has the lowest energy," says Matthias Meier. "That makes sense, because that is the state that the system most often assumes. But in our case, there is a second state that plays a central role: A so-called metastable state."

Both the platinum atoms and the iron oxide surface can switch back and forth between different quantum physical states. The ground state, with the lowest energy, is stable. When the system changes to the metastable state, it inevitably returns to the ground state after a short time - like the cat trying to get to the top on an unstable climbing pole. But in the catalytic conversion of carbon monoxide, it is enough for the system to be in the metastable state for a very short time: Just as a brief moment in a wobbly climbing state might be enough for the cat to catch a bird with its paw, the catalyst can convert carbon monoxide in the metastable state.

When the carbon monoxide is first introduced, two platinum atoms attach together to make a dimer. When the temperature is high enough, the dimer can move to a less favourable position where the surface oxygen atoms are less weakly bound. In the metastable state, the iron oxide changes its atomic structure precisely at this point, releasing the oxygen atom that the carbon oxide needs to form carbon dioxide, which instantly flies away - completing the catalysis process. "If we include these previously unaccounted for short-term states in our computer simulation, we get exactly the result that was also measured in the experiment," says Matthias Meier.

"Our research result shows that in surface physics you often need a lot of experience," says Gareth Parkinson. "If we hadn't studied very different chemical processes over the years, we probably never would have solved this puzzle." Recently, artificial intelligence has also been used with great success to analyze quantum chemical processes - but in this case, Parkinson is convinced, it probably would not have been successful. To come up with creative solutions outside of what was previously thought possible, you probably need humans after all.

Research Report: "CO oxidation by Pt2/Fe3O4: Metastable dimer and support configurations facilitate lattice oxygen extraction"

Related Links
Vienna University of Technology
Space Technology News - Applications and Research

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

From lab to slab rubber concrete moves into residential markets
Adelaide, Australia (SPX) Mar 31, 2022
A novel approach to rubber recycling could see end-of-life tyres repurposed into concrete for residential constructions as new research from the University of South Australia shows that it can provide an economically viable and sustainable alternative to conventional concrete. Working with RMIT University, researchers demonstrated that crumb rubber concrete is a safe, green alternative for residential construction in Australia, proving a much-needed new market for end-of-life tyres. Lead res ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Winning technologies benefit NASA and Industry

Ax-1: why the private mission to the International Space Station is a gamechanger

Commercial research expands aboard the International Space Station

Station waits for private astronauts during science and spacewalk preps

Astranis Space Technologies signs with SpaceX for dedicated launch in 2023

NASA delays final test for moon shot

SpaceX completes static fire test ahead of first private astronaut mission to ISS

Amazon signs with Arianespace for 18 Ariane 6 launches to deploy Project Kuiper constellation

Balancing Risks in the Seitah Region for Flight 24

NASA's Pioneering Ingenuity Mars Helicopter Awarded Collier Trophy

Sol 3435: Maybe We Should Switch Names

First audio recorded on Mars reveals two speeds of sound

Tianzhou 2 re-enters Earth's atmosphere, mostly burns up

Shenzhou XIII astronauts prep for return

China's Tianzhou-2 cargo craft leaves space station core module

China's space station to support large-scale scientific research

Amazon signs on launch partners for space internet

Blue Canyon Technologies to supply spacecraft buses for HelioSwarm Mission

Terran Orbital begins trading on the New York Stock Exchange

Viasat, Inmarsat to boost UK space industry investments

Neurons are fickle. Electric fields are more reliable for information

The platinum riddle

D-Orbit Launches its Fifth ION Satellite Carrier Mission

Players with disabilities score in video game world

Cosmic SETI ready to stream data for technosignature research from Jansky VLA

Prenatal protoplanet upends planet formation models

Hubble finds a planet forming in an unconventional way

Miniaturized laser systems to seek out traces of life in space

Juice's journey and Jupiter system tour

Pluto's giant ice volcanos may have formed from multiple eruption events

Chaos terrains on Europa could be shuttling oxygen to ocean

Searching for Planet Nine

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.