New catalysts to cut CO poisoning of fuel cells - Scientists in the US and Japan have developed new nanoparticle catalysts which can reduce carbon monoxide poisoning of fuel cells.
The catalyst is made from tungsten added to nano particles of titanium dioxide. The catalyst is then coated with platinum to make the electrode. Tungsten is good at resisting carbon monoxide poisoning, but is not a good electrical conductor; titanium dioxide is a good electrical conductor.
When the electrode was used in a fuel cell supplied with hydrogen contaminated with 2 per cent carbon monoxide, performance was reduced by 5 per cent - it would normally be reduced by 30 per cent.
Ultimately, this electrode could make it possible to make fuel cells for cars which last much longer.
The research was made by Cornell University, the National Institute for Materials Science in Ibaraki, Japan, and the University of Pennsylvania.
It is very difficult to avoid carbon monoxide in hydrogen streams, if the hydrogen is made from hydrocarbons (gasoline, gas, and ethanol) - most of the carbon will oxidise to carbon dioxide, but some of it will only oxidise to carbon monoxide.
In a normal fuel cell, the carbon monoxide can bind to platinum catalysts and stop them from working.
Until now, the only way to block carbon monoxide poisoning was to use a platinum / ruthenium catalyst, but this is very expensive.
Source: The Hydrogen JournalEnd
|