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Aluminum Alloy Releases Hydrogen From Water
mdsolar writes "PhysOrg is reporting on a method of releasing hydrogen from water by oxidizing aluminum in an alloy with gallium. In the presence of water the aluminum oxidizes, leaving aluminum oxide, gallium, and hydrogen gas. The Purdue scientists who discovered the effect think this could help to overcome difficulties with hydrogen storage. Quoting: 'On its own, aluminum will not react with water because it forms a protective skin [of aluminum oxide] when exposed to oxygen. Adding gallium keeps the film from forming, allowing the aluminum to react with oxygen in the water.'"
Just another way of converting electrical energy into a form that can be used later.
We need to have a source of reliable cheap electricity to make the aluminum. And we don't at this time.
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The aluminum smelting process requires vast amounts of electricity.
quoting a random googled page : "On average, around the world, it takes some 15.7 kWh of electricity to produce one kilogram of aluminium from alumina. Design and process improvements have progressively reduced this figure from about 21kWh in the 1950's."
so it doesnt matter that it produces hydrogen. It's almost assured coal equivalent to or greater than the tank of gas it replaces was burned somewhere to get the aluminum.
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It's not a closed system because it requires energy to recycle the aluminum and gallium. Also, it's still not terribly efficient, since it requires 1 lb of aluminum per mile you drive.
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But it's not one of the major hurdles that needs to be overcome to use hydrocarbons. Regarding the "hydrogen economy," Hydrogen is actually pretty far from ideal as a storage mechanism. Liquid hydrocarbons turns out to be one of the best ways to store hydrogen all around, and the infrastructure's already in place to handle it.
The way to get off "foreign oil" is to produce synthetic octane/diesel fuel. Since it's already possible to do this in a number of ways, the thing holding us back from kicking the oil habit is that oil is freakin' cheap. It's already made, all you have to do is pump it out of the ground. And maybe a little fractional distillation, but that's peanuts compared to the energy needed to synthesize liquid hydrocarbon fuel (or any easily transportable fuel, really.)
We'd all better hope that the carbon trapped in easy-to-get spots is pretty much insignificant atmosphere-wise, 'cause the cat's out of the bag, and it's not going to stop being pumped till it's gone.
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Actually, once the reaction takes place you have Alumina, i.e. Aluminum Oxide. Although you could say this item is "recyclable" it's actually quite worthless to do so. It takes an incredible amount of energy to convert it back to aluminum, not to mention the process of creating aluminum from alumina oxide requires the reaction of a carbon anode which generates carbon dioxide. Also, the electrolysis has to occur at high temperatures which are probably generated with coal. My guess it would be far more efficient to just continue using the alumina that is efficiently mined and transported in bulk than to try recycling the byproduct from each vehicle. The gallium might be much rarer, I don't know.
So, pure hydrogen on the other hand can be generated by a simple science experiment. Just try making your own aluminum at home and see how easy it is.