The use of hydrogen as a practical, widespread alternative fuel to gasoline might have taken a big step forward with the announcement of a method for recycling a hydrogen fuel storage material.
Scientists have demonstrated that a lightweight material, ammonia borane, can feasibly store hydrogen on vehicles. Once the hydrogen is spent, the alternative fuel can be efficiently added back into the material.
"This is a critical step if we want to use hydrogen as a fuel for the transportation industry," David Dixon, professor of chemistry of the University of Alabama and co-author of an article published in the journal Science last week, said in a statement.
In this approach, ammonia borane in a fuel tank produces hydrogen which releases energy when combined with oxygen in the vehicle's fuel cell. That energy is then converted to electricity that powers an electric motor. Water is the only emission.
After hydrogen is released from the ammonia borane, a residue – which the researchers refer to as "spent fuel" – remains.
"The spent fuel stays in the car, and we need to add hydrogen back to it in order to use it again," Dixon said. "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."
Practical, efficient and affordable storage of hydrogen has been one of the challenges in making the powering of electrical motors via hydrogen fuel cells a viable alternative to traditional gasoline powered engines. Benefits of hydrogen fuel cell technology include cleaner air and less dependence on foreign oil.
The announcement of what scientists call a "fuel regeneration process" overcomes one key hurdle. While there has been much progress toward making the widespread use of hydrogen fuel cell technology practical, Dixon said other challenges remain.
"The basic three steps – the initial synthesis, the controlled release of hydrogen, and the regeneration of fuel – are actually in pretty good shape," Dixon said. "The next piece is to get a cheap source of hydrogen that doesn't come from coal or fossil fuels."