That's a show stopper for widespread use, and there isn't enough platinum in the world to produce enough hydrogen to power very many cars.
One team, at Australia's Monash University, discovered that birnessite, a common mineral that produces a black stain on rocks, also works as a catalyst for splitting water into hydrogen and oxygen. It mimics the way plants split water into fuel for growth, suggesting that there may be even more effective -- and cheaper -- substitutes for platinum.
Scientists at Stanford University are following a similar course. They are studying natural catalysts used by plants and other organisms to produce fuel for growth, and it looks like a common compound, molybdenum sulfide, might be "an inexpensive solution" for catalyzing hydrogen production, the researchers reported earlier this month. However, a different catalyst must be found to isolate the other component of water -- oxygen -- and the team is experimenting with other prospects. Left free to roam, oxygen will clog the chemical solar cell that powers the system.
Following a different course, scientists at Los Alamos National Laboratory have had some success experimenting with a compound of carbon, iron and cobalt as a catalyst.
But even if the cheap production of hydrogen is closer, how do you tame the stuff once you've got it? Hydrogen is the smallest atom, and thus it can squeeze in and out of every pore. You could use it today to run the family car, but it would seep past every hose clamp, and don't even think of keeping it in an ordinary gas tank. What is needed is some kind of matrix that is capable of holding a lot of hydrogen in a small place.
The hurdle here is to create seemingly solid stuff that has room for hydrogen. Rice University scientists say they have found that a class of material known as metallacarborane can store hydrogen better than the benchmarks set by DOE's hydrogen program for 2015. Other researchers at the University of California, Los Angeles, claim to have already solved the storage problem with a brand new material that works something like a sponge.
So if all of this pans out, is a hydrogen car in your future? It looks more likely now than it did just a couple of years ago. But success is not guaranteed. There's no way to distribute it like gasoline, but it seems reasonable that such an infrastructure would evolve fairly quickly if the potential is as great as so many scientists believe. However, there's a little problem with the competition.
Gasoline and diesel engines are getting better and better. So are batteries, leading to widespread acceptance of hybrids and electric vehicles. And sticker shock at the local hydrogen car dealership is likely to be awful as a brand new technology weaves its way through the marketplace.
So it's not going to happen tomorrow. But much progress is being made.