Nav: Home

ORNL microscopy captures real-time view of evolving fuel cell catalysts

November 19, 2015

OAK RIDGE, Tenn., Nov. 19, 2015 -- Atomic-level imaging of catalysts by scientists at the Department of Energy's Oak Ridge National Laboratory could help manufacturers lower the cost and improve the performance of emission-free fuel cell technologies.

Fuel cells rely on costly platinum catalysts to enable the reactions that convert chemical energy into electricity. Alloying platinum with noble metals such as cobalt reduces the overall cost, but such alloyed catalysts vary in performance based on their atomic structure and processing history.

An ORNL team used scanning transmission electron microscopy to track atomic reconfigurations in individual platinum-cobalt nanoparticle catalysts as the particles were heated inside the microscope. The in-situ measurements -- acquired in real time in the vacuum of the microscope column -- allowed the researchers to collect atomic level data that could not be obtained with conventional microscopy techniques. The results are published in Nature Communications.

"This is the first time individual nanoparticles have been tracked this way -- to image the structural and compositional changes at the atomic level from the start of an annealing process to the finish," ORNL coauthor Karren More said.

Very small changes in the positions of platinum and cobalt atoms affect the catalyst's overall activity and selectivity, so annealing -- a gradual heating, holding, and cooling process -- is often used to modify the alloy's surface structure. The ORNL in situ microscopy experiments documented exactly what, when and how specific atomic configurations originate and evolve during the annealing process.

"You can anneal something from room temperature to 800 degrees Celsius, but you don't know at which point you should stop the process to ensure the best catalytic performance," lead author Miaofang Chi said. "Because you don't know how the particle evolves, you might be missing the optimum surface configuration."

The atomic-level detail in the ORNL study will guide researchers and manufacturers who want to fine-tune their catalysts' atomic structure to meet the demands of a specific application.

"This work paves the way towards designing catalysts through post-synthesis annealing for optimized performance," Chi said.

-end-

The study is published as "Surface faceting and elemental diffusion behavior at atomic scale for alloy nanoparticles during in situ annealing." Coauthors are ORNL's Miaofang Chi, Karren More, Andrew Lupini and Lawrence Allard; Johns Hopkins University's Chao Wang; University of Pittsburgh's Yinkai Lei and Guofeng Wang; and Argonne National Laboratory's Dongguo Li, Nenad Markovic, and Vojislav Stamenkovic.

The research was sponsored by the Fuel Cell Technologies Office in DOE's Office of Energy Efficiency and Renewable Energy, and microscopy was performed at ORNL's Center for Nanophase Materials Sciences, a DOE Office of Science User Facility.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's 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 science.energy.gov.

Image: https://www.ornl.gov//sites/default/files/annealingIllust_1.jpeg

Caption: Models of platinum-cobalt nanoparticle catalysts illustrate how specific atomic configurations originate and evolve as the particles are heated. Illustration by Andy Sproles, Oak Ridge National Laboratory, U.S. Department of Energy.

NOTE TO EDITORS: You may read other press releases from Oak Ridge National Laboratory or learn more about the lab at http://www.ornl.gov/news. Additional information about ORNL is available at the sites below:
Twitter - http://twitter.com/ornl
RSS Feeds - http://www.ornl.gov/ornlhome/rss_feeds.shtml
Flickr - http://www.flickr.com/photos/oakridgelab
YouTube - http://www.youtube.com/user/OakRidgeNationalLab
LinkedIn - http://www.linkedin.com/companies/oak-ridge-national-laboratory
Facebook - http://www.facebook.com/Oak.Ridge.National.Laboratory

DOE/Oak Ridge National Laboratory
Electrocatalyst nanostructures key to improved fuel cells, electrolyzers
Purdue University scientists' simulations have unraveled the mystery of a new electrocatalyst that may solve a significant problem associated with fuel cells and electrolyzers.
Nanoalloys 10 times as effective as pure platinum in fuel cells
A new type of nanocatalyst can result in the long-awaited commercial breakthrough for fuel cell cars.
Drug combination boost PARP inhibitor response in resistant ovarian cancer
A new Dana-Farber study shows patients with platinum resistant ovarian cancer who wouldn't be expected to respond to a PARP inhibitor had partial shrinkage of their tumor with the addition of a kinase inhibitor.
Promising results obtained with a new electrocatalyst that reduces the need for platinum
A group of Aalto University researchers led by professors Tanja Kallio and Kari Laasonen has developed a manufacturing method for electrocatalysts that only uses one hundredth of the amount of platinum generally used in commercial products.
University of South Carolina discovery of widespread platinum may help solve Clovis people mystery
No one knows for certain why the Clovis people and iconic beasts -- mastodon, mammoth and saber-toothed tiger -- living some 12,800 years ago suddenly disappeared.
UNIST researchers get green light to commercialize metal-air batteries
A new study, affiliated with South Korea's Ulsan National Institute of Science and Technology (UNIST), has introduced a new way to increase energy efficiency of metal-air batteries.
For platinum catalysts, tiny squeeze gives big boost in performance, Stanford study says
Squeezing a platinum catalyst a fraction of a nanometer nearly doubles its catalytic activity, a finding that could lead to better fuel cells and other clean energy technologies, say Stanford scientists.
Ames Laboratory scientists create first intermetallic double salt with platinum
Scientists at the US Department of Energy's Ames Laboratory are being credited with creating the first intermetallic double salt with platinum.
Results from the PLATINUM DIVERSITY study presented at TCT 2016
A dedicated stent study conducted exclusively in women and minority patients evaluated clinical outcomes within the era of contemporary PCI, comparing these results to a parallel cohort of white male patients.
Putting the pressure on platinum
Hokkaido University researchers have synthesised a uniquely structured platinum-based superconducting material by applying extreme high pressure.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.

Now Playing: Radiolab

Truth Trolls
Today, a third story of folks relentlessly searching for the truth. But this time, the truth seekers are an unlikely bunch... internet trolls.


Now Playing: TED Radio Hour

Rethinking School
For most of modern history, humans have placed smaller humans in institutions called schools. But what parts of this model still work? And what must change? This hour, TED speakers rethink education.TED speakers include teacher Tyler DeWitt, social entrepreneur Sal Khan, international education expert Andreas Schleicher, and educator Linda Cliatt-Wayman.