Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


X-rays and electrons join forces to map catalytic reactions in real-time


New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions

A new technique pioneered at the U.S. Department of Energy's Brookhaven National Laboratory reveals atomic-scale changes during catalytic reactions in real time and under real operating conditions.

This is a series of scanning transmission electron microscopy (STEM) images of platinum nanoparticles, tracking their changes under different atmospheric pressure reaction conditions.

Credit: Brookhaven National Laboratory

A team of scientists used a newly developed reaction chamber to combine x-ray absorption spectroscopy and electron microscopy for an unprecedented portrait of a common chemical reaction. The results demonstrate a powerful operando technique--from the Latin for "in working condition"--that may revolutionize research on catalysts, batteries, fuel cells, and other major energy technologies.

"We tracked the dynamic transformations of a working catalyst, including single atoms and larger structures, during an active reaction at room temperature," said study coauthor and Brookhaven Lab scientist Eric Stach. "This gives us unparalleled insight into nanoparticle structure and would be impossible to achieve without combining two complementary operando techniques."

The results were published online June 29, 2015, in the journal Nature Communications.

To prove the efficacy of this new mosquito-sized reaction chamber--called a micro-reactor--the scientists tracked the performance of a platinum catalyst during the conversion of ethylene to ethane, a model reaction relevant to many industrial synthesis processes. They conducted x-ray studies at the National Synchrotron Light Source (NSLS) and electron microscopy at the Center for Functional Nanomaterials (CFN), both DOE Office of Science User Facilities.

"The size, shape, and distribution of catalysts affect their efficiency and durability," said study coauthor Ralph Nuzzo of the University of Illinois at Urbana-Champaign. "Now that we can track those parameters throughout the reaction sequence, we can better determine the ideal design of future catalysts--especially those that drive energy-efficient reactions without using expensive and rare materials like platinum."

Hidden behind the curtain

In transmission electron microscopy (TEM), a focused electron beam passes through the sample and captures images of the nanoparticles within. This is usually performed in a pristine environment--often an inactive, low-pressure vacuum--but the micro-reactor allowed the TEM to operate in the presence of an atmosphere of reactive gases.

"With TEM, we take high-resolution pictures of the particles to directly see their size and distribution," said Stach, who leads CFN's Electron Microscopy Group. "But with the micro-reactor, some signals were too small to detect. Particles smaller than a single nanometer were hidden behind what we call the resolution curtain of the technique."

Another technique was needed to peer behind the curtain and reveal the full reaction story: x-ray absorption spectroscopy (XAS).

In XAS, a beam of x-rays bombards the catalyst sample and deposits energy as it passes through the micro-reactor. The sample then emits secondary x-rays, which are measured to identify its chemical composition--in this instance, the distribution of platinum particles.

"The XAS and TEM data, analyzed together, let us calculate the numbers and average sizes of not one, but several different types of catalysts," said coauthor and Yeshiva University scientist Anatoly Frenkel, who led the x-ray experiments. "Running the tests in an operando condition lets us track broad changes over time, and only the combination of techniques could reveal all catalytic particles."

Versatile micro-reactor

The new micro-reactor was specifically designed and built to work seamlessly with both synchrotron x-rays and electron microscopes.

"Everything was exquisitely controlled at both NSLS and CFN, including precise measurements of the progress of the catalytic reaction," Frenkel said. "For the first time, the operando approach was used to correlate data obtained by different techniques at the same stages of the reaction."

A relatively straightforward mathematical approach allowed them to deduce the total number of ultra-small particles missing in the TEM data.

"We took the full XAS data, which incorporates particles of all sizes, and removed the TEM results covering particles larger than one nanometer--the remainder fills in that crucial sub-nanometer gap in our knowledge of catalyst size and distribution during each step of the reaction," Frenkel said.

Added Stach, "In the past, scientists would look at data before and after the reaction under model conditions, especially with TEM, and make educated guesses. Now we can make definitive statements."

Brighter, faster experiments

The collaboration has already extended this operando micro-reactor approach to incorporate two additional techniques--infrared and Raman spectroscopy--and plans to introduce other complex and complementary x-ray and electron probe techniques over time.

NSLS ended its 32-year experimental run in the fall of 2014, but its successor--the just-opened National Synchrotron Light Source II (NSLS-II)--is 10,000 times brighter and promises to rapidly advance operando science.

"Each round of data collection took six hours at NSLS, but will take just minutes at NSLS-II," Stach said. "Through Laboratory Directed Research and Development funding, we will be part of the initial experiments at the Submicron Resolution X-ray (SRX) Spectroscopy beamline this summer, dramatically increasing the time resolution of the experiments and letting us track changes in a more dynamic fashion. And that's just one of the NSLS-II beamlines where we plan to deploy this technique."

The ethylene to ethane reaction happens at room temperature, but other new micro-reactors can operate at up to 800 degrees Celsius--more than hot enough for most catalytic reactions-- and will increase the versatility and applicability of the approach.

In the near future, this same micro-reactor approach will be used to explore other crucial energy frontiers, including batteries and fuel cells.

"We are seeing the emergence of a very powerful and versatile technique that leverages both NSLS-II and the CFN," said Stach, who was recently named Special Assistant for Operando Experimentation for Brookhaven's Energy Sciences Directorate. "This approach complements the many facilities being developed at Brookhaven Lab for operando energy research. Our goal is to be world leaders in operando science."


Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation for the State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit applied science and technology organization.

Media Contact

Justin Eure


Justin Eure | EurekAlert!

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>