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Scientists develop catalyst that cleans diesel emissions without platinum


August 17, 2012

Nanostellar has developed a mineral catalyst that outperforms platinum at a fraction of the cost (Photo: Shutterstock)

Nanostellar has developed a mineral catalyst that outperforms platinum at a fraction of the cost (Photo: Shutterstock)

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Diesel engines are a classic example of good news and bad news. The good news is that diesel engines are much more fuel efficient than petrol engines. The bad news is that they belch out some pretty nasty emissions like nitric oxide and nitrogen dioxide. The good news is that catalytic converters can scrub those out. The bad news is that last Friday the platinum needed by the converters is selling for US$1,473.10 an ounce. Now the good news is that a team at Nanostellar in Redwood, California, has developed a mineral catalyst that outperforms platinum at a fraction of the cost.

Platinum is an excellent catalyst, though it does have a few problems. One of the biggest at the moment is that a violent labor dispute in South Africa sent the price skyrocketing. Also, with the World Health Organization classifying diesel exhaust as a carcinogen, the potential demand for platinum for catalytic converters for hundred of millions of vehicles far outstrips supply. The Nanostellar team, led by Dr. Kyeongjae “K.J.” Cho, professor of materials science and engineering and physics at UT Dallas and co-founder of Nanostellar, determined that a mineral catalyst would be a cheaper alternative.

Dr. Kyeongjiae "K.J." Cho, professor of materials science and engineering and physics at UT Dallas (Photo: University of Texas at Dallas)

Reporting their findings in the August 17 issue of Science, Cho relates that computer modelling showed that mullite was a cost-effective substitute. Mullite is a silicate mineral discovered on the Isle of Mull, Scotland in 1924. It’s rare in nature, but a synthetic version is produced commercially for use in various porcelains, such as crucibles and heating balls. It has a very high melting point of 1840 C (3344 F) and as a mixed-phase oxide mineral it makes a very attractive catalyst. In addition, laboratory tests indicate that converters using mullite would have 45 percent lower emissions than with platinum.

Ideal and stepped crystal surface of Noxicat (Image: Geoffrey McCool)

“Our goal to move completely away from precious metals and replace them with oxides that can be seen commonly in the environment has been achieved,” Dr. Cho said. “We’ve found new possibilities to create renewable, clean energy technology by designing new functional materials without being limited by the supply of precious metals.”

The new catalyst, called Noxicat, will be developed for commercial use and further work is planned to determine its application in fuel cells.

Source: University of Texas at Dallas via Phys.org

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

How resistant to sulfur poisoning are the oxide catalysts compared to platinum?


This does nothing to eliminate the carcinogenic properties of diesel exhaust though does it? Diesel exhaust contains nano-particles of carbon which are a severe hazard to human health. These engines require advanced particle filters to remove particles from exhaust gasses and strict controls to ensure effective burning of fuel to prevent the formation of carcinogens.

Ian McIntosh

re; Ian McIntosh

Could you please provide a link?


Yes the problem will be that while the new material costs a fraction of platimum it won't stop the commerailized company that forms from that research to sell it for a mere 10% less than platinum.

Rocky Stefano

so does this mean thieves will start stealing cat converts out of late model diesel engines?

Mexoplex 5 Million

re; Ian McIntosh

Do you work for a company that manufactures diesel exhaust filters.

Once you can break down the NOx reducing unburned is simply a mater of increasing the oxygen ratio.


"...a violent labor dispute in South Africa sent the price skyrocketing."

No. The price of precious metals have been going up for a dozen years. A worldwide rise in commodity prices is not the result of an increase in value. It is reflective of the issue of fiat money, i.e., paper money is going down in value, resulting in a flight to real wealth.

Ian: ICE exhaust is bad. We can't change that. All we can do is cut down on the exhaust. The Noxicat does that.

Don Duncan

what is the nanoparticle emission ? They have ignored the most dangerous component. It has increase. The I.C.E . will be banned for that reason. The ban will happen overnite.

Stewart Mitchell

Nanoparticles affect human health?! Big deal - the planet's health is more important and the global reduction of CO2 outwieghs localised (to human environments) production of diesel particulates.

Gerry Lavell
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