MIT: Harnessing solar energy like plants do
Much more chemical research will be needed to make solar energy technologically and economically viable. When plants photosynthesize, they produce high-energy sugars such as glucose; the chemists aim to produce hydrogen fuel or hydrocarbons such as methanol.When sunlight strikes the artificial photosynthesis device, high-energy photons will split water into hydrogen and oxygen. One of the researchers' biggest challenges is developing inexpensive catalysts that can split water efficiently. Platinum does the job, but it is very rare and expensive, so the researchers are focusing on more abundant metals, such as iron, cobalt, nickel and manganese.
With hydrogen fuel cells, the need for hydrocarbon fuels isn't clear, at least to me. Maybe it has to do with the distribution infrastructure we already have in place? With that, maybe the idea is that the ability to produce liquid hydrocarbon fuels would result in more immediate, short-term benefit?
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Need for Hydrocarbons
The need for hydrocarbons lies in a few places. Hydrogen gas tends to be difficult to store on it's own, eventually working its way out of any container. Liquid Hydrocarbons are much easier to store and meter while dispensing. In addition, there is much higher density per volume OR per molecule in hydrocarbons than hydrogen gas. H2 + O2 = H20 while HxCx + O2 = H20 + CO2. As you can see there are additional product from the combustion of hydrocarbons. There is a lot of energy stored between the carbons in the carbon chains than there are in burning H2. When you add double or triple bonds between carbons, you get even MORE energy. Check out the difference between Propane, Propene, and Propyne (single, double, and triple bonded hydrocarbon with 3 carbons). Propyne is also known as Metylacetylene... or part of MAPP gas... a fuel used for welding. Try doing THAT with just H2.
Thanks for the explanation.
Thanks for the explanation.
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