Navigation Links
First metallic nanoparticles resistant to extreme heat
Date:11/30/2009

PITTSBURGHA University of Pittsburgh team overcame a major hurdle plaguing the development of nanomaterials such as those that could lead to more efficient catalysts used to produce hydrogen and render car exhaust less toxic. The researchers reported Nov. 29 in Nature Materials the first demonstration of high-temperature stability in metallic nanoparticles, the vaunted next-generation materials hampered by a vulnerability to extreme heat.

Gtz Veser, an associate professor and CNG Faculty Fellow of chemical and petroleum engineering in Pitt's Swanson School of Engineering, and Anmin Cao, the paper's lead author and a postdoctoral researcher in Veser's lab, created metal-alloy particles in the range of 4 nanometers that can withstand temperatures of more than 850 degrees Celsius, at least 250 degrees more than typical metallic nanoparticles. Forged from the catalytic metals platinum and rhodium, the highly reactive particles work by dumping their heat-susceptible components as temperatures rise, a quality Cao likened to a gecko shedding its tail in self-defense.

"The natural instability of particles at this scale is an obstacle for many applications, from sensors to fuel production," Veser said. "The amazing potential of nanoparticles to open up completely new fields and allow for dramatically more efficient processes has been shown in laboratory applications, but very little of it has translated to real life because of such issues as heat sensitivity. For us to reap the benefits of nanoparticles, they must withstand the harsh conditions of actual use."

Veser and Cao present an original approach to stabilizing metallic catalysts smaller than 5 nanometers. Materials within this size range boast a higher surface area and permit near-total particle utilization, allowing for more efficient reactions. But they also fuse together at around 600 degrees Celsiuslower than usual reaction temperatures for many catalytic processesand become too large. Attempts to stabilize the metals have involved encasing them in heat-resistant nanostructures, but the most promising methods were only demonstrated in the 10- to 15-nanometer range, Cao wrote. Veser himself has designed oxide-based nanostructures that stabilized particles as small as 10 nanometers.

For the research in Nature Materials, he and Cao blended platinum and rhodium, which has a high melting point. They tested the alloy via a methane combustion reaction and found that the composite was not only a highly reactive catalyst, but that the particles maintained an average size of 4.3 nanometers, even during extended exposure to 850-degree heat. In fact, small amounts of 4-nanometer particles remained after the temperature topped 950 degrees Celsius, although the majority had ballooned to eight-times that size.

Veser and Cao were surprised to find that the alloy did not simply endure the heat. It instead sacrificed the low-tolerance platinum then reconstituted itself as a rhodium-rich catalyst to finish the reaction. At around 700 degrees Celsius, the platinum-rhodium alloy began to melt. The platinum "bled" from the particle and formed larger particles with other errant platinum, leaving the more durable alloyed particles to weather on. Veser and Cao predicted that this self-stabilization would occur for all metal catalysts alloyed with a second, more durable metal.


'/>"/>

Contact: Morgan Kelly
mekelly@pitt.edu
412-624-4356
University of Pittsburgh
Source:Eurekalert

Related biology news :

1. Sugary cola drinks linked for first time to higher risk of gestational diabetes
2. First global conference on systems and enterprises at new Stevens location, Washington, DC, Dec. 3-4
3. First-ever blueprint of a minimal cell is more complex than expected
4. Is 80-year-old mistake leading to first species to be fished to extinction?
5. Pacific Biometrics Inc. Reports First Quarter Operating Results
6. Scientists are first to unlock the mystery of creating cultured pearls from the queen conch
7. First draft of the pig: Researchers sequence swine genome
8. New study reveals first ever method to genetically identify all 8 tuna species
9. Scientists are first to observe the global motions of an enzyme copying DNA
10. UT Southwestern patient first in North Texas to receive newest-generation heart failure device
11. Seeing previously invisible molecules for the first time
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/27/2016)... Jan. 27, 2016  Rite Track, Inc. a leading ... West Chester, Ohio announced today the ... staff, based in Austin, Texas , ... to provide modifications, installations and technical support offerings for ... of PLUS, commented, "PLUS has provided world class service ...
(Date:1/21/2016)... --> ... report "Emotion Detection and Recognition Market by Technology (Bio-Sensors, NLP, ... Voice Recognition and Others), Services, Application Areas, End ... published by MarketsandMarkets, the global Emotion Detection and ... Billion by 2020, at a CAGR of 31.9%, ...
(Date:1/15/2016)... Puerto Rico , Jan. 15, 2016 ... big and small to find new ways to ensure ... culture. iOS and Android ... based on biometrics, transforming it into a hardware authorization ... that users swipe their fingerprint on their KodeKey enabled ...
Breaking Biology News(10 mins):
(Date:2/5/2016)... 5, 2016 On Thursday, February 11, ... for community, health and disaster services, and the ... to enhance care coordination and service delivery for the ... need and to better connect service providers to the ... San Diego has handled more than ...
(Date:2/5/2016)... drug discovery and development company, Novogen Limited (ASX:NRT; NASDAQ: ... Mr John O,Connor , and new Deputy Chairman, Mr ... Garner , has also been formally appointed to the Board ... Iain Ross , will resume his role on the Board ... has also been formally appointed to the Board as an ...
(Date:2/4/2016)... - New FDA action date of July 22, ... July 22, 2016   --> - ...   - Lifitegrast has the potential to be the ... signs and symptoms of dry eye disease in adults ... product approved in the U.S. in the past decade indicated for the treatment of ...
(Date:2/4/2016)... ... , ... Shimadzu Scientific Instruments will showcase several new products, ... sessions, and present on the analysis of mycotoxins and medical cannabis at the ... at the Georgia World Congress Center in Atlanta, Georgia. , Attendees should ...
Breaking Biology Technology: