Hydrogen From Vitamin C

Scientists have taken photosynthetic machinery from bacteria and rewired it with a platinum cluster catalyst to create a nanomachine capable of producing hydrogen gas from vitamin C. The light-driven, self-assembling apparatus can pump out H₂ for “up to three months without special treatment or chemical preservatives,” notes the research team, led by Barry D. Bruce of the University of Tennessee, Knoxville (Nat. Nanotechnol., DOI: 10.1038/nnano.2009.315). The researchers estimate that the system operates at an efficiency equivalent to converting 6% of U.S.-incident solar radiation into usable fuel and could “exceed the best biomass-to-fuel schemes by a factor of 25.” Furthermore, unlike many biomass strategies, the system could be placed in nonarable regions so it doesn’t compete with food production. To make H₂, vitamin C (ascorbate) from the bioreactor’s buffered acidic solution is oxidized by means of a thermostable bacterium’s cytochrome c protein. The bacterial photosystem I complex nabs the electrons from cytochrome c, boosts the electrons’ energy level, and passes them on to the platinum catalyst. The catalyst then reduces two H⁺ ions into H₂.