MIT’s ‘artificial leaf’ transforms sunlight into storable fuel


MIT research team led by professor Daniel Nocera has developed an ‘artificial leaf’ that aptly describes its job of converting sunlight directly into chemical fuel – hydrogen and oxygen gas which can be stored for later use as a source of energy.

The ‘artificial leaf’ made up of a thin silicon solar cell fastened on either side with different catalytic materials needs no external circuits or controls to operate. When the leaf is placed in a container of water and exposed to sunlight, it quickly releases bubbles – oxygen on one side and hydrogen on another. If a barrier is used the separate the sides, then the bubbles can be collected separately and stored to generate power later. The streams of oxygen and hydrogen bubbles could be fed to a fuel cell that combines them into the water to generate an electric current.

The ‘artificial leaf’ is lightweight, portable, and the “solar water-splitting cells” can power right from individual houses to utility-scale power plants.  Other than capturing and storing the streams of bubbles, there is not much of the technology’s equipment. Just drop it in a container, and it does its job.

Nocera, the Henry Dreyfus Professor of Energy and professor of chemistry at MIT explains that they need to take the experiment a step further by breaking down the ‘artificial leaf’ into smaller particles to split water molecules similar to the process photosynthetic algae rather than leaves. He reasons that small particles will have much more surface area available for the efficient harnessing of the sun’s energy.

Commercial production of the ‘artificial leaf’ is still not on the cards as systems to collect, store, and use the gases are yet to be developed. But Nocera is happy that the research is heading in the correct direction.

Professor James Barber, a biochemist from Imperial College London who finds this discovery as necessary as Nocera’s earlier findings of cobalt-based catalyst in 2008, warns that much work remains to resourcefully use the protons derived from the water-splitting reaction for hydrogen production.

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