Are Hydrogen Fuel for Cars Next?

University of Alabama scientists working on hydrogen fuel for cars

University of Alabama chemistry professor David Dixon(University of Alabama)

A University of Alabama professor and three students are part of a research team that may have taken a big step forward in hydrogen fuel for cars.

In a report published in today's issue of the journal Science, the team, which also includes members of the Los Alamos National Laboratory, outlines a new way to recycle a hydrogen-rich compound that can be used for an environmentally friendly fuel.

The patented process could be a reality in about a decade, figures David Dixon, a professor of chemistry at the University of Alabama and co-author of the study. He said Dow Chemical is already doing computer models of what an ammonia borane production and recycling factory would look like -- and that's exciting for those looking for an alternative to gasoline.

"It's been a lot of fun to work on," Dixon said. "It's good basic science, but it's in service of a national need."

In the current quest for eco-friendly cars, technology is heading in two directions: either battery-powered electric vehicles, like the few models on the road now, or electric cars that get their energy from hydrogen fuel cells.

In some ways, hydrogen is the ideal fuel, because it's lightweight and its only byproduct is water, not the smog-producing carbon dioxide that comes from burning fossil fuels. But hydrogen gas is hard to store, because it must be held under high pressure -- a potential danger in car accidents -- and the tiny atoms can leak out of many tanks. There also isn't an easy means of production yet.

So researchers such as Dixon have been working on compounds that have hydrogen bonded to them and can be forced to release it to power a car's engine, either through heat or other means.

His team focuses on ammonia borane, which consists of borane -- a compound of boron and hydrogen atoms --nitrogen and hydrogen. The borane comes from borate ore -- the same stuff that goes into that old-fashioned laundry detergent, Borax.

Although Dixon said there's enough borane to power the country's entire fleet, there's not enough of it to keep throwing it out when the hydrogen's burned off. Plus, that creates the expense and hassle of dealing with piles of spent fuel.

So the group of authors, including UA post-doctoral student Monica Vasiliu, graduate student Edward Garner III and junior J. Pierce Robinson, set out to find an efficient way of recharging the spent ammonia borane. According to the paper, they found a simple way to reactivate the old fuel by exposing it to the chemical hydrazine in liquid ammonia for about 24 hours.

That means future customers could either trade in their detachable hydrogen fuel tanks at a service station for new ones -- much like returning propane tanks at the grocery store -- or have the borane sucked out of the tank and replaced with fresh fuel, Dixon said. The borane would then be trucked to a plant to be recharged with hydrogen for an almost endless supply of energy.

There are still plenty of challenges. So far, they don't have the ammonia borane recycling at 100 percent, but they're close, at least on a small scale. The cost works out to about two to three times the price of gasoline, an equivalent of about $8 or $9 a gallon, though that could come down, he said. And there may need to be better ways to produce the hydrazine needed for recycling.

Dixon said he and his lab plan to keep refining the process. They're also following other paths to alternative fuels, including looking at how plants could be turned into jet fuel. He likes the challenges of practical application, he said.

"When you start mixing economic ideas with science, you have to rethink some of the science," Dixon said. "It forces you to think about different things."