Engineering On The Edge

Most of us don’t pay much mind to leaves until they need raking, or they clog our gutters. But leaves play an important role in the plant kingdom, using the energy from sunlight to convert carbon dioxide into organic compounds that serve as “food” for the plants — photosynthesis, a process you may dimly recall from your high school biology class.

Researchers at MIT have developed an artificial “leaf” that can likewise use the energy from sunlight to create a chemical fuel that can be stored and used as an energy source. The leaf is actually a silicon solar cell with different catalytic materials bonded onto its two sides. It doesn’t require any external wires or circuits. Just placing it in a container of water and exposing it to sunlight will cause it to generate streams of oxygen and hydrogen bubbles.

You can read more about the device from the original paper, written by lead researcher Daniel Nocera, in in the Sept. 30 issue of Science.

Conceivably, a solar collection system based on this concept could use sunlight to produce hydrogen and oxygen that could be stored in tanks, then fed into a fuel cell to generate electricity. Nocera hopes such systems could be deployed in less developed areas of the world where access to electricity is limited.

“I think there’s going to be real opportunities for this idea,” Nocera says. “You can’t get more portable — you don’t need wires, it’s lightweight,” and it doesn’t require much in the way of additional equipment, other than a way of catching and storing the gases that bubble off. “You just drop it in a glass of water, and it starts splitting it.”

Watch a video of the ‘leaf’ creating oxygen and hydrogen bubbles:

Source: MIT