Solar Hydrogen at Night
Ever since I can remember, scientists have been trying to figure out photosynthesis–and do it ourselves. In elementary school, back mid-twentieth century, we were shown a film (the kind you feed through a projector, and hope it doesn’t break) where a little cartoon creature labeled “photosynthesis” says, “And I’m NOT going to tell you!” Outside immunology, bacterial and plant photosynthesis is the most complex topic in my textbook–the one that took three editions to get straight (almost).
Yet the fundamental aim of photosynthesis is surprisingly simple. You absorb light, split water, and store the energy in chemical bonds. Plants mainly store it in sugar, amino acids, vitamins–messy molecules useful to them. But some bacteria, for unaccountable reasons, store much of their energy in hydrogen–and get rid of it.
Why do the bacteria give up hydrogen, losing some of their energy for sugar, amino acids, etc.? New-age evolutionists would suggest that the hydrogen help out their fellow microbes somehow, down in the muck of the bogs where these purple bacteria live, and that overall their fitness is enhanced–well, read the book for details. Or check out Carrie Harwood’s research.
Tom Meyer and colleagues try to imitate plants and bacteria. They’ve made a chromophore (did you find the structure on the internet? I don’t see it, surprise.) that specifically splits water and stores almost all the energy as H2 (supposedly; I don’t see the details published). The idea of such a chromophore is to imitate what chlorophylls have done for at least three billion years. Chlorophylls are amazingly beautiful and intricate molecules that absorb a photon, store it in a chain of conjugated double bonds, and apply it to a precise reaction such as splitting water. And releasing hydrogen fuel–the kind we’ve been saying could drive your next car, and maybe store at night as formate. In fact the next target of Meyer’s group is “to reduce carbon dioxide, a greenhouse gas, to a carbon-based fuel such as formate.”
Could we actually use solar to get rid of some of our excess CO2?