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Photocatalyst Cracks Water with Sunlight
lonenut writes: "With fuel cell laptop batteries in the news lately, I thought this article on water-cracking photocatalysts would be good reading. A bit short on details, but apparently Zhigang Zou of the NIAIST in Tsukuba, Japan is working on a promising catalyst which creates hydrogen and oxygen from water and sunlight. I look forward to someday watering my laptop just like the houseplants."
No it doesn't
a) catalyssts are by definition resuable
b) there are other source of minerals than just the Earth. (There aren't any other useful sources of hydrocarbons on the other hand).
Were that I say, pancakes?
Building the solar pannel requiers more energy than you get out of it. Same as a battery. It's only "efficient" for the end user.
Petrolium is efficient because we are just harvesting millions of years of sunlight-and-plant stored energy. In real terms, it's not efficient at all. Ethanol is more efficient, brewing burnable liquid fuel out of sugar, or using lye and methanol to crack vegetable oil into "diesel" fuel. Or just burn the veggie oil directly, like Heir Diesel did in his original engines.
All of these convert sunlight into fuel, with various efficiencies and usefulness. I think the direct use of veggie oil to be the best myself, but one still has to press the oil out!
The answer, I believe, is to use them all. Bio-diesel, veggie oil, ethanol, hydrogen, tide and wave forces, wind, sunlight, petrolium.
The "scarce resource" idea is a myth. 150 years ago, whale oil was an important strategic national resource. Silica is as common as sand, and more valuable than gold when formed into a computer chip.
Bob-
The Ludwig von Mises Institute. The reasoning individuals economics
Why? When you "burn" the hydrogen to recover the
energy, guess what you get back?
Every bloody emperor has his hand up history's skirt [Peter Hammill/VdGG]
I believe that this is no longer true. The latest generations of cells are much thinner and lighter (less silicon to refine and melt so less energy) and more efficient than earlier generations.
You still need to recharge your laptop with Hydrogen, and it will polute just as much as batteries do today(very little)
;)
There is a funamental difference between the use of hydrogen for power in a fuel cell and the use of a normal cell.
You 'make' a cell. It's made of some pretty nasty things. There are around 70 million mobile phones in the UK, each of which has around 100 grammes of heavy metal in their rechargable (but not infinitely so) cells. In a few years each of these cells will need to be replaced. By my calculation that's 7 million kilogrammes, or 7000 tonnes of heavy metals that needs to be processed and/or recycled (or, thrown away). That's a hell of a lot of material for a place the size of the UK.
A hydrogen fuel cell does not contain such nastiness and, baring wear and tear and failure, would last at least as long. Additionally, the oxidation of hydrogen (which is ultimately where the energy comes from) produces water. Not slightly nasty water, but pure water. The kind of thing which tastes awful
I think you'd find that a hydrogen fuel cell industry would be far better for the environment and cheaper to do (lower displosal, recycling, replacement cost) than any other chemical storage power supply.
The part of the equation which is missing is an efficient (read, cheap) way of producing hydrogen. Sunlight is clean and free - if we don't use it then it's wasted. The sun emits quite a lot of it continuously. Using a million times more of it than we necessarilly need is still a hell of a lot cheaper and better than drilling for crushed and fermented vegetation below rock strata. If it can be made commercially viable, I for one am all for the use of H2 for power. The advantages are clear: the only thing missing is a cheap and plentiful supply of H2.
Ian Woods