15 June 2010
Hydrogen seems like a logical choice for fuel - it's energy dense and emits only water upon combustion - but upon closer examination we see that it's extremely expensive to make from water, so all the hydrogen in production today is made from fossil fuels. But Gerardine Botte at Ohio University has figured out an easy and efficient way to break the bonds in urea to produce hydrogen. The process consumes roughly one quarter of the energy needed to electrolyze water. And, yes, the world has a fairly plentiful (and renewable) supply of urea. Maybe not enough to power all our cars, but it's a start.
Very simply, an inexpensive electrode oxidizes the urea creating two H2 molecules, nitrogen gas and potassium carbonate. Success! None of these chemicals are bad for the environment, and, indeed, are useful, saleable byproducts. The urea doesn't need to be pure or anything either, the process works with human urine, meaning that port-o-johns could someday become useful hydrogen-generation stations.
Of course, we don't have oceans or rivers or lakes of urea (good thing) so it is a more limited feedstock than water. The good news is, what we do have of it is a waste product, and (especially in the case of livestock) already needs to be managed more effectively for environmental reasons. So it certainly wouldn't hurt to have an extra source of hydrogen gas while giving the world a reason to more effectively manage its waste.