Future Car - The Problems with Hydrogen Part II
Problems with Hydrogen
This is an extension to the original article on the problems with hydrogen.
This hub will concentrate on hydrogen production, not storage. e.g. problems with producing hydrogen and a potential new solution. Of course storage has to be mentioned so please read on.
Two Main Problems with Hydrogen
The first problem is storage. Hydrogen does not exist in a gaseous state on earth. Even if it did the most efficient and economical way to store it would require upwards of 5,000 Pounds per Square Inch and extremely well made containers to withstand those pressures. Both the container and the energy to reach those pressures are expensive.
Second, because it's lighter than air any hydrogen naturally produced migrates up and out of the atmosphere and into space.This means that any hydrogen we mean to use has to be extracted from molecules of which hydrogen is just a part.
Despite it being the most abundant element in the universe hydrogen bonds readily with other elements to form molecules. Most of the hydrogen on earth comes in two forms, both bonded almost inextricably with something else.
The first is natural gas. The second is water.
So despite being plentiful it's time consuming and expensive to "de-bond" the hydrogen from the other elements. Stripping hydrogen from it's bonds with other elements is also expensive in energy required and, of course, once we've gotten it we are back to the first problem; storage.
Electrolysis of Water
To date the most efficient means of extracting hydrogen involves immersing an electrode and cathode in water, running an electric current between the two, and thus stripping the hydrogen from the oxygen forming the two distinct gases.
Platinum as Catalyst
Platinum, at almost $2,000 per ounce, has been the most efficient material used as catalyst in the production of hydrogen from water. But platinum, despite being one very tough and useful metal, is oxidized during the process, "wears" away over time and ends up being an expensive type of material for this extraction of gas. Add to this the cost of stopping the process to replace the platinum, though up to now the best metal, the process becomes an expensive proposition.
Additionally, with this platinum catalyst, the water has to be within a tight temperature range, have no impurities, but must also be in a particular Ph range, and will not work at all with sea-water.
Suddenly, with all these conditions, electrolysis of water is not a cheap proposition at all, never mind the storage issue.
So science has been in a race of sorts to find a substitute that will make the conversion of water to the two primary gases cheap, efficient and cost effective. This has been a daunting task.
U.S. Department of Energy Lawrence Berkeley National Laboratory & University of California at Berkeley researchers Jeffrey Long, Christopher Chang and Hemamala Karunadasa have come up with a platinum substitute. Not only is the material far cheaper than platinum it does not suffer from oxidation, does not require the water to have additives, works with dirty water, and even works with sea-water; the most abundant source of water on the planet.
In fact moly-oxo is about seventy (70) times cheaper to produce than pure platinum or roughly $28.00 per ounce.
Because Moly-oxo places so few demands on both the water and the conversion apparatus the idea of generating hydrogen by converting sunlight to electricity and then using that power to split the water molecule now seems much more economical and far closer to feasibility.
Long, Chang and Karunadasa continue to experiment with other molybdenum compounds in case the moly-oxo discovery turns out the be a catalyst that is less efficient than those yet discovered.
The Remaining Problem
If moly-oxo is indeed the "holy-grail" of electrolysis of water the storage problem remains. Still, this was two major problems (other methods of producing hydrogen also produce CO2) that now seems to be down to one.
Since Nickle Metal Hydride, a metallic substance that acts like a hydrogen sponge, is still very expensive to produce (making storage this way impracticable) perhaps this or some other team (Long started his research with hydrogen storage) will finally find a substitute for this expensive substance and the "hydrogen economy" can begin once and for all.