The top image shows a nanonet magnified 50,000 times. At bottom, a
flexible nanonet rolls up when poked by the tip of a scanning tunneling microscope.
One problem with solar cells is that they only produce electricity during the day. A promising way to use the sun’s energy more efficiently is to enlist it to split water into hydrogen gas that can be stored and then employed at any time, day or night. A cheap new nanostructured material could prove an efficient catalyst for performing this reaction. Called a nanonet because of its two-dimensional branching structure, the material is made up of a compound that has been demonstrated to enable the water-splitting reaction. Because of its high surface area, the nanonet enhances this reaction.