“Artificial leaf” device turns water and sunlight into hydrogen fuel

Researchers from Rice University have built a simple new solar-powered device that can create hydrogen for fuel by splitting water. The system is very similar to other “artificial leaf” designs, but the team says it’s self-sufficient and relatively cheap to produce.

The system is made up of a perovskite solar cell, hooked up to electrodes made of a catalyst that electrolyzes the water. When sunlight hits the solar cell, it produces electricity that powers the catalyst, which then splits the water into oxygen and hydrogen. These bubble up to the surface where they can be collected for use.

The sunlight-to-hydrogen efficiency sits at around 6.7 percent, which is relatively high for these types of systems. But the most useful feature, the team says, is just how self-contained the new design is. The solar cell and the electrodes are all in one unit – the solar cell components are encased inside a polymer shell that protects them from water damage while still letting sunlight through. The electrodes sit on the outside where they can split the water.

The idea is that this device could basically be dropped into some water with direct sunlight and left to run for long periods of time, producing hydrogen as needed.

A schematic and vertical slice of the artificial leaf design, comprised of a solar cell and catalysts
A schematic and vertical slice of the artificial leaf design, comprised of a solar cell and catalysts

Jia Liang

“With a clever system design, you can potentially make a self-sustaining loop,” says Jun Lou, lead author of the study. “Even when there’s no sunlight, you can use stored energy in the form of chemical fuel. You can put the hydrogen and oxygen products in separate tanks and incorporate another module like a fuel cell to turn those fuels back into electricity.”

The team says that the perovskite solar cell has also been tweaked so that it doesn’t require expensive components like platinum. Instead, those have been switched out for cheap elements like carbon. This should bring down the cost to produce the devices and make them more viable for commercial production.

Along with hydrogen fuel, artificial leaf designs are also being explored as ways to produce electricity, drugs, fertilizers, syngas and other useful chemical compounds.

The new study was published in the journal ACS Nano.

Source: Rice University

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