A team of researchers at the University of Alabama recently published an article in the journal Science detailing a new process that could recycle hydrogen fuel, making hydrogen fuel cell technology much more practical, efficient and affordable. In collaboration with an experimental team at Los Alamos National Laboratory, the University of Alabama team compiled and modeled data to predict the kinds of chemical reactions that occur when using different compounds in a hydrogen fuel cell.

Hydrogen has been suggested as a cleaner, widespread alternative to gasoline, but developmental roadblocks such as cost and efficiency have kept it from really taking off as a viable substitute, said David Dixon, professor of chemistry at the University of Alabama and co-author of the article published in March.

“Think of hydrogen like gasoline works today, except it’s a gas rather than a liquid,” explained Dixon. “Right now we dump our combustion out of our tailpipe. With hydrogen, we release it, but we don’t let the compound left over out into the environment; it stays in the car. We’re going to have to take that spent fuel – the waste – and add hydrogen back to it so that we can have a new fuel.”

According to Dixon, researchers have already looked into recycling methods for hydrogen but found the process to be economically inefficient. However, the newly discovered process solves many of these economic concerns by using a more stable compound called ammonia borane.

A GM hydrogen fuel cell vehicle refuels at a Shell hydrogen refueling station

A GM hydrogen fuel cell vehicle refuels at a Shell hydrogen refueling station. Researchers at the University of Alabama used experiments from the Los Alamos National Laboratory to improve hydrogen fuel cell efficiency using hydrogen recycling methods. Credit: DOE

“We take ammonia borane as a solid of liquid, a simple stable compound to handle, and we can release the hydrogen when we need it to run the fuel cell and the car,” Dixon said.

The ammonia borane, stored in a fuel tank, will produce hydrogen, which then reacts chemically with oxygen in the vehicle’s fuel cell to release energy. The energy is converted to electricity and powers the vehicle’s electric motor. Water is the only emission, but a residue remains after the hydrogen is released from the ammonia borane. The researchers refer to the residue as “spent fuel.” Efficient ways to utilize the spent fuel is what the Los Alamos and University of Alabama teams were trying to discover.

“This is a critical step if we want to use hydrogen for the transportation industry,” said Dixon. “What this paper describes is an efficient way to add the hydrogen back to make the ammonia borane again. And, it can be done in a single reactor.”

Other issues must still be resolved before hydrogen is widely adopted as an alternative to gasoline, said Dixon. He added that the nation’s current infrastructure is not ready to support hydrogen production, distribution and use. Another hurdle in the process is fuel production, which is currently neither economically or environmentally sustainable because it relies heavily on fossil fuel-generated electricity to power the chemical reactions that produce hydrogen fuels.

The next step “is to get a cheap source of hydrogen that doesn’t come from coal or fossil fuels,” Dixon said. “We have to continue to find a good way to make hydrogen by using solar power to split water.”

As research continues and new discoveries like the University of Alabama and Los Alamos teams’ are made, hydrogen will continue to become a more viable alternative to gasoline dependency. Dixon said he believes the use of hydrogen as an alternative fuel will be widespread within a decade as long as progress continues to be made.




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