The device is an advanced solar cell, no bigger than a typical playing card, which is left floating in a pool of water. Then, much like a natural leaf, it uses sunlight to split the water into its two core components, oxygen and hydrogen, which are stored in a fuel cell to be used when producing electricity.
Nocera’s leaf is stable — operating continuously for at least 45 hours without a drop in activity in preliminary tests — and made of widely available, inexpensive materials — like silicon, electronics and chemical catalysts. It’s also powerful, as much as ten times more efficient at carrying out photosynthesis than a natural leaf.
With a single gallon of water, Nocera says, the chip could produce enough electricity to power a house in a developing country for an entire day. Provide every house on the planet with an artificial leaf and we could satisfy our 14 terrawatt need with just one gallon of water a day.