Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Scientists boost catalytic activity for key chemical reaction in fuel cells: New platinum-based catalysts with tensile surface strain could improve fuel cell efficiency

Dong Su in the control room of the aberration-corrected scanning transmission electron microscope (Hitachi HD2700C) at the Center for Functional Nanomaterials, a US Department of Energy Office of Science User Facility at Brookhaven Lab. On the computer screens are images of the platinum-based nanoplates that Su and his collaborators developed. The nanoplates have a thick, ordered shell of platinum that surrounds a platinum and lead alloyed core. This special structure is thought to be behind the high catalytic activity and stability of the nanoplates.
CREDIT
Brookhaven National Laboratory
Dong Su in the control room of the aberration-corrected scanning transmission electron microscope (Hitachi HD2700C) at the Center for Functional Nanomaterials, a US Department of Energy Office of Science User Facility at Brookhaven Lab. On the computer screens are images of the platinum-based nanoplates that Su and his collaborators developed. The nanoplates have a thick, ordered shell of platinum that surrounds a platinum and lead alloyed core. This special structure is thought to be behind the high catalytic activity and stability of the nanoplates. CREDIT Brookhaven National Laboratory

Abstract:
Fuel cells are a promising technology for clean and efficient electrical power generation, but their cost, activity, and durability are key challenges to commercialization. Today's fuel cells use expensive platinum (Pt)-based nanoparticles as catalysts to accelerate the reactions involved in converting the chemical energy from renewable fuels--such as hydrogen, methanol, and ethanol--into electrical energy. Catalysts that incorporate less expensive metals inside the nanoparticles can help reduce cost and improve activity and durability, but further improvements to these catalysts are required before these fuel cells can be used in vehicles, generators, and other applications.

Scientists boost catalytic activity for key chemical reaction in fuel cells: New platinum-based catalysts with tensile surface strain could improve fuel cell efficiency

Upton, NY | Posted on December 19th, 2016

Now, scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, California State University-Northridge, Soochow University, Peking University, and Shanghai Institute of Applied Physics have developed catalysts that can undergo 50,000 voltage cycles with a negligible decay in their catalytic activity and no apparent changes in their structure or elemental composition. As described in a paper published online in the December 16 issue of Science, the catalysts are "nanoplates" that contain an atomically ordered Pt and lead (Pb) core surrounded by a thick uniform shell of four Pt layers.

To date, the most successful catalysts for boosting the activity of the oxygen reduction reaction (ORR)--a very slow reaction that significantly limits fuel cell efficiency--have been of the Pt-based core-shell structure. However, these catalysts typically have a thin and incomplete shell (owing to their difficult synthesis), which over time allows the acid from the fuel cell environment to leach into the core and react with the other metals inside, resulting in poor long-term stability and a short catalyst lifetime.

"The goal is to make the ORR as fast as possible with catalysts that have the least amount of platinum and the most stable operation over time," said corresponding author Dong Su, a scientist at Brookhaven Lab's Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility, who led the electron microscopy work to characterize the nanoplates. "Our PtPb/Pt catalysts show high ORR activity and stability--two parameters that are key to enabling a hydrogen economy--placing them among the most efficient and stable bimetallic catalysts reported for ORR."

Lattice strain for enhanced catalytic performance

In previous studies, scientists have shown that ORR activity can be optimally enhanced in core-shell catalysts by compressing the Pt atoms on one specific lattice surface plane called Pt(111). This compressive strain is induced by adding metals smaller in size than Pt, such as nickel, to the shell's core, and has the effect of weakening the binding of oxygen to the Pt surface, where the catalytic reaction takes place.

"The ideal ORR catalyst needs to help break bonds (between oxygen molecules) and form bonds (between oxygen and hydrogen), so oxygen can't be too strongly or too weakly bound to the platinum surface," explained Su. "Scientists have focused their research on the compressively strained Pt(111) surfaces, in which Pt atoms are squeezed across the surface, because the oxygen binding energy is optimized. In general, scientists thought that tensile strain on the same surface plane would result in overly strong binding of oxygen and thus hinder the ORR reaction."

But Su and his collaborators showed that introducing a large tensile strain along one direction of a different surface plane, Pt(110), could also improve ORR catalytic activity. They added Pb (which is larger than Pt) to the core of the Pt shell, causing the Pt atoms to stretch across the surface.

Nanoplate characterization and durability testing

After the research group led by Xiaoqing Huang, corresponding author from Soochow University, synthesized the nanoplates, Su characterized their structure and elemental composition at the CFN. Using electron diffraction patterns and images from high-resolution scanning transmission electron microscopy (STEM), both of which reveal the relative positions of atoms, he confirmed the core-shell structure and the composition and sequence of the atoms. To verify that the core contained Pt and Pb and that the shell contained Pt, he measured the change in energy of the electrons after they interacted with the nanoplates--a technique called electron energy-loss spectroscopy.

With this information, the team distinguished how the nanoplates formed with the individual Pt and Pb atoms. To their surprise, the surface planes were not Pt(111) but Pt(110), and these Pt(110) planes were under biaxial strain--compressive strain in one direction and tensile strain in the other--originating from the PtPb core.

In durability tests simulating fuel cell voltage cycling, Su's collaborators found that after 50,000 cycles there was almost no change in the amount of generated electrical current. In other words, the nanoplates had minimal decay in catalytic activity. After this many cycles, most catalysts exhibit some activity loss, with some losing more than half of their original activity.

Microscopy and synchrotron characterization techniques revealed that the structure and elemental composition of the nanoplates did not change following durability testing. "The electron microscopy work at CFN was critical in explaining why our nanoplates showed such high catalytic activity and stability," said Huang.

Compared to commercial Pt-on-carbon (Pt/C) catalysts, the team's PtPb/Pt nanoplates have one of the highest ORR activities to date, taking the amount of Pt used into account, and excellent durability. The team's nanoplates also showed high electrocatalytic activity and stability in oxidation reactions of methanol and ethanol.

"We believe the relatively thick and complete Pt layers play an important role in protecting the core," said Su.

To understand how the high ORR activity originates in the nanoplates, the scientists calculated the binding energy between oxygen atoms and Pt atoms on the surface. Their calculations confirmed the tensile strain on the Pt(110) surface was responsible for the enhanced ORR activity.

"This work opens up a new way to introduce large tensile strain on the stable Pt(110) plane to achieve very high activity for oxygen reduction catalysis. We believe that our approach will inspire efforts to design new nanostructured catalysts with large tensile strain for more efficient catalysis," said corresponding author Shaojun Guo of Peking University.

Eventually, the laboratory-level electrocatalysts will need to be tested in a larger fuel cell system, where real-world variables--such as pollutants that could impact surface reactivity--can be introduced.

###

In addition to the electron microscopy work performed at CFN, supported by DOE's Office of Science, this work involved theoretical calculations by Gang Lu's group at California State University-Northridge and synchrotron characterization by Jing-Yuan Ma at Shanghai Synchrotron Radiation Facility. This work was further supported by the National Basic Research Program of China, the National Natural Science Foundation of China, the Ministry of Science and Technology of the People's Republic of China, Soochow University, Peking University, the Young Thousand Talents Program, the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the U.S. Army Research Office.

####

About Brookhaven National Laboratory
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 science.energy.gov.

For more information, please click here

Contacts:
Ariana Tantillo

631-344-2347

Copyright © Brookhaven National Laboratory

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

RELATED JOURNAL ARTICLE:

Related News Press

News and information

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Leti to Demo 1st Wireless UNB Transceiver for ‘Massive Internet of Things’ at RFIC 2017 and IMS 2017: Leti Will also Present Three Papers & Two Workshops on 5G Communications IC Design, from RF to mm-Wave, During IMS 2017 and RFIC 2017 in Hawaii May 24th, 2017

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Chemistry

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Sandia develops math techniques to improve computational efficiency in quantum chemistry May 5th, 2017

Laboratories

NREL’s Advanced Atomic Layer Deposition Enables Lithium-Ion Battery Technology: May 10th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

Sandia develops math techniques to improve computational efficiency in quantum chemistry May 5th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Oddball enzyme provides easy path to synthetic biomaterials May 17th, 2017

Possible Futures

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Leti Will Demo World’s-first WVGA 10-µm Pitch GaN Microdisplays for Augmented Reality Video at Display Week in Los Angles: Invited Paper also Will Present Leti’s Success with New Augmented Reality Technology That Reduces Pixel Pitch to Less than 5 Microns May 22nd, 2017

Discoveries

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Materials/Metamaterials

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Self-healing tech charges up performance for silicon-containing battery anodes May 15th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

CCNY physicists demonstrate photonic hypercrystals for control of light-matter interaction May 5th, 2017

Announcements

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Leti to Demo 1st Wireless UNB Transceiver for ‘Massive Internet of Things’ at RFIC 2017 and IMS 2017: Leti Will also Present Three Papers & Two Workshops on 5G Communications IC Design, from RF to mm-Wave, During IMS 2017 and RFIC 2017 in Hawaii May 24th, 2017

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

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

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Military

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Gas gives laser-induced graphene super properties: Rice University study shows inexpensive material can be superhydrophilic or superhydrophobic May 15th, 2017

'Hot' electrons don't mind the gap: Rice University scientists find nanogaps in plasmonic gold wires enhance voltage when excited May 8th, 2017

Energy

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Fed grant backs nanofiber development: Rice University joins Department of Energy 'Next Generation Machines' initiative May 10th, 2017

Discovery of new transparent thin film material could improve electronics and solar cells: Conductivity is highest-ever for thin film oxide semiconductor material May 6th, 2017

Automotive/Transportation

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Self-healing tech charges up performance for silicon-containing battery anodes May 15th, 2017

UnitySC Announces Wafer Thinning Inspection System; Win from Power Semiconductor IDM for Automotive: Leading IDM Selects New 4See Series Automated Defect Inspection Platform for Power Semiconductor Automotive Applications May 11th, 2017

Fuel Cells

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

MIT Energy Initiative awards 10 seed fund grants for early-stage energy research May 4th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

It's basic: Alternative fuel cell technology reduces cost: Study sets performance targets for metal-free fuel cell membrane December 13th, 2016

Research partnerships

Three-dimensional graphene: Experiment at BESSY II shows that optical properties are tuneable May 24th, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project