Despite being the most naturally abundant element in the known universe, monatomic hydrogen (H) is remarkably difficult to produce in an environmentally responsible manner. Currently, the commercial production of "free hydrogen" generally involves the separation of hydrogen and oxygen atoms found in water H2O by means of reacting superheated steam with natural gas. While this prevalent procedure proves effective, it also generates substantial amounts of CO2, a greenhouse gas likely responsible for global warming.
This past July, chemists at Argonne National Laboratory's Center for Nanoscale Materials and Chemical Sciences and Engineering Division as well as Northwestern University's Chemistry Department discovered a new means of producing free hydrogen without the consumption of fossil fuels. Their nanoscale hydrogen generator features an approximately one atom thick sheet of two-dimensional graphene, pure carbon atoms joined together in a honeycomb lattice structure. On this graphene sheet, the researchers placed a bacteria found in single-celled organisms, bacteriorhodospin (bR), which is known to absorb sunlight and convert it into chemical energy in the form of proton motion. They also placed a titanium dioxide catalyst (TiO2) on the graphene and nanoparticles of platinum on top of this catalyst. When visible light is absorbed by the bR protein and graphene sheet, electrons are directed towards the titanium dioxide catalyst. At the same time, the bR protein releases protons which converge at the platinum nanoparticles and interact with the electrons on the titanium dioxide catalyst to form diatomic molecules of hydrogen (H2).
While this hydrogen generator currently exists only on the nanoscale, they remain hopeful that one day a similar procedure may be scaled-up so greater quantities of hydrogen are produced and the resulting hydrogen fuel may begin to replace the burning of fossil fuels as our primary source of usable energy.
No comments:
Post a Comment