Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Unprecedented view of a single catalyst nanoparticle at work: X-rays reveal compositional changes on active surface under reaction conditions

X-ray analysis provided a complete 3D image of an individual catalyst nanoparticle nd revealed changes in its surface tension and surface chemical composition during different modes of operation.

CREDIT
Science Communication Lab for DESY
X-ray analysis provided a complete 3D image of an individual catalyst nanoparticle nd revealed changes in its surface tension and surface chemical composition during different modes of operation. CREDIT Science Communication Lab for DESY

Abstract:
A DESY-led research team has been using high-intensity X-rays to observe a single catalyst nanoparticle at work. The experiment has revealed for the first time how the chemical composition of the surface of an individual nanoparticle changes under reaction conditions, making it more active. The team led by DESY’s Andreas Stierle is presenting its findings in the journal Science Advances. This study marks an important step towards a better understanding of real, industrial catalytic materials.

Unprecedented view of a single catalyst nanoparticle at work: X-rays reveal compositional changes on active surface under reaction conditions

Hamburg, Germany | Posted on October 1st, 2021

Catalysts are materials that promote chemical reactions without being consumed themselves. Today, catalysts are used in numerous industrial processes, from fertiliser production to manufacturing plastics. Because of this, catalysts are of huge economic importance. A very well-known example is the catalytic converter installed in the exhaust systems of cars. These contain precious metals such as platinum, rhodium and palladium, which allow highly toxic carbon monoxide (CO) to be converted into carbon dioxide (CO2) and reduce the amount of harmful nitrogen oxides (NOx).

“In spite of their widespread use and great importance, we are still ignorant of many important details of just how the various catalysts work,” explains Stierle, head of the DESY NanoLab. “That’s why we have long wanted to study real catalysts while in operation.” This is not easy, because in order to make the active surface as large as possible, catalysts are typically used in the form of tiny nanoparticles, and the changes that affect their activity occur on their surface.

Surface strain relates to chemical composition

In the framework of the EU project Nanoscience Foundries and Fine Analysis (NFFA), the team from DESY NanoLab has developed a technique for labelling individual nanoparticles and thereby identifying them in a sample. “For the study, we grew nanoparticles of a platinum-rhodium alloy on a substrate in the lab and labelled one specific particle,” says co-author Thomas Keller from DESY NanoLab and in charge of the project at DESY. “The diameter of the labelled particle is around 100 nanometres, and it is similar to the particles used in a car’s catalytic converter.” A nanometre is a millionth of a millimetre.

Using X-rays from the European Synchrotron Radiation Facility ESRF in Grenoble, France, the team was not only able to create a detailed image of the nanoparticle; it also measured the mechanical strain within its surface. “The surface strain is related to the surface composition, in particular the ratio of platinum to rhodium atoms,” explains co-author Philipp Pleßow from the Karlsruhe Institute of Technology (KIT), whose group computed strain as a function of surface composition. By comparing the observed and computed facet-dependent strain, conclusions can be drawn concerning the chemical composition at the particle surface. The different surfaces of a nanoparticle are called facets, just like the facets of a cut gemstone.

When the nanoparticle is grown, its surface consists mainly of platinum atoms, as this configuration is energetically favoured. However, the scientists studied the shape of the particle and its surface strain under different conditions, including the operating conditions of an automotive catalytic converter. To do this, they heated the particle to around 430 degrees Celsius and allowed carbon monoxide and oxygen molecules to pass over it. “Under these reaction conditions, the rhodium inside the particle becomes mobile and migrates to the surface because it interacts more strongly with oxygen than the platinum,” explains Pleßow. This is also predicted by theory.

“As a result, the surface strain and the shape of the particle change,” reports co-author Ivan Vartaniants, from DESY, whose team converted the X-ray diffraction data into three-dimensional spatial images. “A facet-dependent rhodium enrichment takes place, whereby additional corners and edges are formed.” The chemical composition of the surface, and the shape and size of the particles have a significant effect on their function and efficiency. However, scientists are only just beginning to understand exactly how these are connected and how to control the structure and composition of the nanoparticles. The X-rays allow researchers to detect changes of as little as 0.1 in a thousand in the strain, which in this experiment corresponds to a precision of about 0.0003 nanometres (0.3 picometres).

Crucial step towards analysing industrial catalyst maerials

“We can now, for the first time, observe the details of the structural changes in such catalyst nanoparticles while in operation,” says Stierle, Lead Scientist at DESY and professor for nanoscience at the University of Hamburg. “This is a major step forward and is helping us to understand an entire class of reactions that make use of alloy nanoparticles.” Scientists at KIT and DESY now want to explore this systematically at the new Collaborative Research Centre 1441, funded by the German Research Foundation (DFG) and entitled “Tracking the Active Sites in Heterogeneous Catalysis for Emission Control (TrackAct)”.

“Our investigation is an important step towards analysing industrial catalytic materials,” Stierle points out. Until now, scientists have had to grow model systems in the laboratory in order to conduct such investigations. “In this study, we have gone to the limit of what can be done. With DESY’s planned X-ray microscope PETRA IV, we will be able to look at ten times smaller individual particles in real catalysts, and under reaction conditions.”

DESY is one of the world’s leading particle accelerator centres and investigates the structure and function of matter – from the interaction of tiny elementary particles and the behaviour of novel nanomaterials and vital biomolecules to the great mysteries of the universe. The particle accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. They generate the most intense X-ray radiation in the world, accelerate particles to record energies and open up new windows onto the universe. DESY is a member of the Helmholtz Association, Germany’s largest scientific association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).

####

For more information, please click here

Contacts:
Thomas Zoufal
Deutsches Elektronen-Synchrotron DESY

Office: +49 40 8998-1666
Expert Contact

Prof. Andreas Stierle
DESY

Office: +49 40 8998-92005

Copyright © Deutsches Elektronen-Synchrotron DESY

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Reference

Related News Press

News and information

Scientists develop promising vaccine method against recurrent UTI November 19th, 2021

How ultracold, superdense atoms become invisible: A new study confirms that as atoms are chilled and squeezed to extremes, their ability to scatter light is suppressed November 19th, 2021

New microscopy method offers 3D tracking of 100 single molecules at once November 19th, 2021

Two is better than one: Single-atom dimer electrocatalyst for green hydrogen production: Nickel-cobalt metal dimer on nitrogen-doped carbon can catalyze electrolysis under both acidic and basic conditions November 19th, 2021

Visualizing temperature transport: An unexpected technique for nanoscale characterization November 19th, 2021

Chemistry

Two is better than one: Single-atom dimer electrocatalyst for green hydrogen production: Nickel-cobalt metal dimer on nitrogen-doped carbon can catalyze electrolysis under both acidic and basic conditions November 19th, 2021

Molecular Sciences Software Institute receives $15 million grant from National Science Foundation October 15th, 2021

Researchers reveal multi-path mechanism in electrochemical CO2 reduction September 17th, 2021

Laboratories

A simple way to get complex semiconductors to assemble themselves: Much like crystallizing rock candy from sugar syrup, the new method grows 2D perovskites precisely layered with other 2D materials to produce crystals with a wide range of electronic properties September 17th, 2021

Scientists demonstrate pathway to forerunner of nanotubes that could lead to widespread industrial fabrication September 17th, 2021

Patterning silicon at the one nanometer scale: Scientists engineer materials’ electrical and optical properties with plasmon engineering August 13th, 2021

Possible Futures

Developing high-performance MXene electrodes for next-generation powerful battery November 19th, 2021

Cancer cells use ‘tiny tentacles’ to suppress the immune system: With the power of nanotechnology, investigators have discovered that cancer cells strengthen by forming nanotubes that they use to suck mitochondria out of immune cells November 19th, 2021

Efficient photon upconversion at an organic semiconductor interface November 19th, 2021

Quantum brain sensors could be crucial in spotting dementia after University of Sussex scientists find they can track brain waves: Sensors introduce important new method to spot bio-marker for brain diseases • Accurate timings of when brain signals fire demonstrated for first tim November 19th, 2021

Discoveries

Developing high-performance MXene electrodes for next-generation powerful battery November 19th, 2021

Efficient photon upconversion at an organic semiconductor interface November 19th, 2021

Quantum brain sensors could be crucial in spotting dementia after University of Sussex scientists find they can track brain waves: Sensors introduce important new method to spot bio-marker for brain diseases • Accurate timings of when brain signals fire demonstrated for first tim November 19th, 2021

New microscopy method offers 3D tracking of 100 single molecules at once November 19th, 2021

Announcements

Efficient photon upconversion at an organic semiconductor interface November 19th, 2021

Quantum brain sensors could be crucial in spotting dementia after University of Sussex scientists find they can track brain waves: Sensors introduce important new method to spot bio-marker for brain diseases • Accurate timings of when brain signals fire demonstrated for first tim November 19th, 2021

New microscopy method offers 3D tracking of 100 single molecules at once November 19th, 2021

Two is better than one: Single-atom dimer electrocatalyst for green hydrogen production: Nickel-cobalt metal dimer on nitrogen-doped carbon can catalyze electrolysis under both acidic and basic conditions November 19th, 2021

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Scientists develop promising vaccine method against recurrent UTI November 19th, 2021

How ultracold, superdense atoms become invisible: A new study confirms that as atoms are chilled and squeezed to extremes, their ability to scatter light is suppressed November 19th, 2021

Energizer atoms: JILA researchers find new way to keep atoms excited November 19th, 2021

Developing high-performance MXene electrodes for next-generation powerful battery November 19th, 2021

Food/Agriculture/Supplements

‘Anti-rust’ coating for plants protects against disease with cellulose nanofiber: Researchers from the University of Tsukuba find that coating soybean plant leaves with cellulose nanofiber offers resistance to infection by Asian soybean rust pathogen September 10th, 2021

Enhanced ambient ammonia photosynthesis by Mo-doped Bi5O7Br nanosheets with light-switchable oxygen vacancies September 3rd, 2021

New technology enables rapid sequencing of entire genomes of plant pathogens May 14th, 2021

Controlling the nanoscale structure of membranes is key for clean water, researchers find January 1st, 2021

Automotive/Transportation

Silver nanoparticles boost performance of microbial fuel cells September 17th, 2021

Gamechanger for clean hydrogen production, Curtin research finds: Curtin University research has identified a new, cheaper and more efficient electrocatalyst to make green hydrogen from water that could one day open new avenues for large-scale clean energy production September 17th, 2021

HKUST scientists discover new mechanisms of activity improvement on bimetallic catalysts for hydrogen generation and fuel cells August 13th, 2021

Breathing new life into fuel cells August 6th, 2021

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project