Microreactors for hydrogen fuel cells

 

Microreactors for hydrogen fuel cells

Publication Date:01-November-2006
11:30 AM US Eastern Timezone
Source:Caroline Moore-Royal Society of Chemistry
Ceramic microreactors show promise for portable electrical power
sources, say US scientists. For the first time, alumina microreactors
containing porous silicon carbide 'monoliths' have been studied for
on-site hydrogen production from readily available hydrocarbons.

Paul Kenis and colleagues at the University of Illinois at
Urbana-Champaign have shown that the silicon carbide monoliths with a
coating of ruthenium act as catalysts for high temperature 'steam
reforming' reactions when integrated in high-density alumina
housings. The monoliths are difficult to make, but, unlike typical
oxide catalysts, their structure doesn't collapse at high
temperatures - which is key to the catalysts' success, said Kenis.

'The microreactors can produce hydrogen from readily available
hydrocarbon fuels such as propane without degradation of performance
over time,' Kenis explained. 'To our knowledge, our microreactors
produce the highest rate of hydrogen per volume compared to any
work.'

Hydrogen fuel cells are highly efficient but there are safety issues
related to distributing and storing compressed hydrogen. This makes
on-site generation of hydrogen a preferred solution. The challenge,
according to Kenis, has been finding ways to do this which avoid
deactivating the catalyst by 'coking' - soot deposition. Kenis'
microreactors can avoid this by operating at temperatures above 800
°C, which is achievable because of the silicon carbide materials used.


The next challenge for scientists is to integrate the microreactors
into a complete fuel processing system, said Kenis..