Argonne researchers produce trace amounts of hydrogen with visible light by merging light-collecting proteins from a single-celled organi...
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| Argonne researchers produce trace amounts of hydrogen with visible light by merging light-collecting proteins from a single-celled organism with a graphene platform. Both graphene and protein absorb the light and re-direct electrons towards the titanium dioxide. Electrons interact with protons at the site of the platinum nanoparticles to produce hydrogen. Credit: John Lambert. |
Researchers at the US Department of Energy's (DOE) Argonne National Laboratory have created a small scale "hydrogen generator" that uses light and a two-dimensional graphene platform to boost production of the hard-to-make element.
The research also unveiled a previously unknown property of graphene. The two-dimensional chain of carbon atoms not only gives and receives electrons, but can also transfer them into another substance.
Hydrogen is virtually everywhere on the planet, but the element is typically bonded with other elements and must be separated from oxygen in H2O to produce free hydrogen. The commercial separation process uses natural gas to react with superheated steam to strip away hydrogen atoms producing hydrogen fuel, but also carbon dioxide —a greenhouse gas byproduct which escapes into the atmosphere.
Argonne's early-stage generator, composed of many tiny assemblies, is proof that hydrogen can be produced without burning fossil fuels. The scale is small, a little smaller than the diameter of spider silk. Scaling this research up in the future may mean that you could replace the gas in your cars and generators with hydrogen—a greener option, because burning hydrogen fuel emits only water vapor.
"Many researchers are looking to inorganic materials for new sources of energy," said Elena Rozhkova, chemist at Argonne's Center for Nanoscale Materials, a DOE Office of Science (Office of Basic Energy Sciences) User Facility. "Our goal is to learn from the natural world and use its materials as building blocks for innovation."
For Rozhkova, this particular building block is inspired by the function of an ancient protein known to turn light into energy. Researchers have long known that some single-celled organisms use a protein called bacteriorhodopsin (bR) to absorb sunlight and pump protons through a membrane, creating a form of chemical energy. They also know that water can be split into oxygen and hydrogen by combining these proteins with titanium dioxide and platinum and then exposing them to ultraviolet light.
There is just one downside: titanium dioxide only reacts in the presence of ultraviolet light, which makes up a mere four percent of the total solar spectrum. If the researchers wanted to power their generators with sunlight, they'd need to improve on that.
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