Artificial Photosynthesis: Making Cheap Hydrogen From Water and LightS

Hydrogen is one of the most promising fuels of the future but right now it's expensive to produce in bulk. Enter the work of a team of Stanford researchers who believe they can make it as cheap as fossil fuels—using just some water and sunlight.

Currently, to make hydrogen out of water and light scientists often use a solar panel to make electricity, which is then used to power a commercial electrolyzer that splits water into hydrogen and oxygen. But the guys at Stanford have been busy rolling those two components together—making it far cheaper in the process.

The electrons created by solar panels can themselves power chemical reactions to split water into hydrogen and oxygen. One half of the electrons can be used to split the atoms and form hydrogen, the other half to fill the electron shells of oxygen atoms.

Problem is, most of the materials you'd choose to make such a device—say, silicon, which is the most efficient—actually corrode incredibly quickly. Metal oxides can do a similar job, but are painfully slow. But the Stanford team hit on an idea: they coated silicon with a thin layer of nickel, just two-billionths of a meter thick, to protect it.

Bingo. Instead of being destroyed by corrosion within hours, the researchers let the solar reactions run for three days before stopping to check for damage. They found none. Not only that, their coated silicon was over ten times faster than alternative metal oxides. The research is published in Science.

That speed makes the new nickel-coated silicon device incredibly efficient. In fact, the researchers believe that they can generate hydrogen in such a way that it can compete with fossil fuels on price. That may take a while, so don't hold your breath, but that hydrogen car? It might not be as silly as it once sounded. [Science via Technology Review]

Image by Alan Levine under Creative Commons license