A cleaner future for diesel engines?

A start-up in the US claims to have devised a way of reducing diesel engine pollutants by almost 50%.

Petrol engines good, diesel engines bad: correct? Well, yes and no. Most people are aware that engines using petrol produce lots of CO2 while diesel engines don’t. But there is growing concern about other gases that pour out of diesel exhausts – notably nitric oxide and nitrogen dioxide.

Researchers at Nanostellar, a start-up company co-founded by a professor at the University of Texas at Dallas (UTD), say they have devised a way of reducing diesel engine pollutants by up to 45%. The innovation could be applied to cars, lorries, planes, ships and heavy machinery. The research, published in Science magazine, was backed by the Texas Advanced Computing Centre and the National Research Foundation of South Korea.

The precious metal platinum is used as a catalyst in diesel exhaust convertors to cut levels of noxious emissions. The Nanostellar team says it has successfully replaced platinum with a man-made version of mullite, a silicate mineral used in porcelain. The result, they say, is a reduction of up to 45% in the pollutants emitted.

“Mullite is not only easier to produce than platinum, but also better at reducing pollution in diesel engines,” says team member Kyeongjae Cho, a professor in materials science, engineering and physics at UTD.

The researchers also plan to explore the use of mullite to replace platinum catalysts in fuel cells, which generate electricity using chemical reactions. Already, the innovation is being offered for commercial applications in automotive diesel exhausts under the trademarked name Noxicat.

Nanostellar says it is also interested in working with potential partners to develop non-automotive applications of the catalyst technology, such as converting coal or biomass into liquid fuels, and capturing waste heat for vehicle air conditioning units. – Bob Cervi

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