Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Catalyst support structures facilitate high-temperature fuel reforming

28.07.2005


The catalytic reforming of liquid fuels offers an attractive solution to supplying hydrogen to fuel cells while avoiding the safety and storage issues related to gaseous hydrogen. Existing catalytic support structures, however, tend to break down at the high temperatures needed to prevent fouling of the catalytic surface by soot.



Now, researchers at the University of Illinois at Urbana-Champaign have developed porous support materials that can withstand the rigors of high-temperature reforming of hydrocarbon fuels.

"These novel materials show great promise for the on-demand reforming of hydrocarbons such as diesel fuel into hydrogen for portable power sources," said Paul Kenis, a professor of chemical and biomolecular engineering at Illinois and a corresponding author of a paper to appear in the August issue of the journal Advanced Functional Materials.


To be useful for hydrocarbon fuel reforming, a catalyst support must have a high surface area, be stable at high temperatures, and possess a low pressure drop.

"Our new materials satisfy all three key requirements," said Kenis, who also is a researcher at the Beckman Institute for Advanced Science and Technology. "They have a large surface area created by a network of interconnected pores. They can operate at temperatures above 800 degrees Celsius, which prevents the formation of soot on the catalytic surfaces. And they have a low pressure drop, which means it takes less pressure to push the fuel through the catalyst."

To fabricate the supports, the researchers begin by placing a polydimethylsiloxane (PDMS) mold onto a flat surface, forming a channel about 500 microns wide that is open at both ends. A slurry containing polystyrene spheres 50 nanometers to 10 microns in diameter is then allowed to flow into the channel from one end by capillary action.

"Once the slurry reaches the other end of the channel, the spheres begin to pack together as a result of solvent evaporation, and the packing process continues toward the inlet end," Kenis said. "After the packing process is completed, we remove any remaining solvent, which leaves a sacrificial template consisting of a bed of closely packed spheres."

Next, the researchers fill the spaces between the spheres with a low-viscosity, preceramic polymer-based liquid. After low-temperature curing, the mold is removed, leaving a stable, freestanding structure.

Lastly, the cured ceramic precursor is pyrolyzed at 1,200 degrees Celsius for two hours in an inert atmosphere. "The polystyrene spheres decompose during the pyrolysis process," Kenis said. "The end result is a silicon carbide or silicon carbonitride replica with a tailored structure of interconnected pores."

The overall size of the replica can be precisely tailored through the dimensions of the mold, Kenis said, while the pore size can be tailored independently by the size of spheres used in the sacrificial template.

To demonstrate the use of these materials as catalyst supports, the researchers coated samples of the porous structure with ruthenium. The structure was then incorporated within a stainless steel housing, where it successfully stripped hydrogen from ammonia at temperatures up to 500 degrees Celsius. In work not yet published, Kenis and his colleagues incorporated the structure in a ceramic housing, which enabled the successful decomposition of ammonia at operating temperatures up to 1,000 degrees Celsius.

The researchers also showed that the silicon carbide and silicon carbonitride structures are stable at temperatures as high as 1,200 degrees Celsius in air, thus showing their promise to perform fuel reforming at temperatures where fouling of the catalyst by soot does not occur.

While the demonstration was performed on a microscale reformer, the material could be used for large-scale reformers, Kenis said, with improvements in the fabrication processes.

James E. Kloeppel | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Power and Electrical Engineering:

nachricht Improved stability of plastic light-emitting diodes
19.04.2018 | Max-Planck-Institut für Polymerforschung

nachricht Intelligent components for the power grid of the future
18.04.2018 | Christian-Albrechts-Universität zu Kiel

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>