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Science Blog ZINC PROJECTS

Harnessing solar energy to mimic photosynthesis

Date: 24-Jun-08
Author: Massachusetts Institute of Technology

Ask any scientist to name Earth's most abundant source of energy, and the answer comes quickly: sunlight. In one hour, the Sun strikes Earth with enough energy to power the entire planet for a year.

Three MIT researchers are building a device that mimics photosynthesis -- the process plants use to capture and store the Sun's vast energy.

MIT chemistry professor Jonas Peters, Dan Nocera, Henry Dreyfus Professor of Energy, and Chris Cummins survey Nocera's piece of their solar energy work on artificial photosynthesis in Nocera's lab. Courtesy: Donna Coveney, MIT

When plants photosynthesize, they produce high-energy sugars such as glucose; the chemists aim to produce hydrogen fuel or hydrocarbons such as methanol.

When sunlight strikes the artificial photosynthesis device, high-energy photons will split water into hydrogen and oxygen. One of the researchers' biggest challenges is developing inexpensive catalysts that can split water efficiently. Platinum does the job, but it is very rare and expensive, so the researchers are focusing on more abundant metals, such as iron, cobalt, nickel and manganese.

Once water molecules are split into hydrogen and oxygen, the hydrogen can power fuel cells.

For solar energy to have a very significant impact on world energy use, it must also yield a liquid fuel that can power cars and other vehicles. To achieve that, hydrogen fuel could be further processed into hydrocarbons such as methanol.

Full story: Harnessing solar energy like plants do