Energy

"Artificial leaf" device turns water and sunlight into hydrogen fuel

"Artificial leaf" device turns...
A new "artificial leaf" design can produce hydrogen fuel from sunlight and water
A new "artificial leaf" design can produce hydrogen fuel from sunlight and water
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A new "artificial leaf" design can produce hydrogen fuel from sunlight and water
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A new "artificial leaf" design can produce hydrogen fuel from sunlight and water
A schematic and vertical slice of the artificial leaf design, comprised of a solar cell and catalysts
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A schematic and vertical slice of the artificial leaf design, comprised of a solar cell and catalysts

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

“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

11 comments
ChairmanLMAO
can i run stanley meyers water car with it?
Phil
how is the hydrogen physically captured and stored?
Aross
Ok so if I understand this, we will be able to create O2 and H2 using electricity created by the solar panel component and then use the H2 and O2 in a fuel cell to create electricity. Why?
Kpar
Aross, the main problem with "renewables" is that they only produce energy when an input is available (sunlight, wind, etc) and that leaves one in the lurch when not. A means of storing the energy to use at night, calm winds and so on might make those renewables viable. Might. But I doubt it.
Captain Danger
@Kpar Using solar to convert water to hydrogen and oxygen implies that storage is taking place. At a later time the fuel is converted into useful work.
However at t a%7 effenincey rate the payback will most likely be so long as to make this technology no so useful.
As to the statement of using chemical energy to power this process when sunlight is not available boggles my mind and make me question this teams credibility. If you have a chemical process available to generate electricity why on earth would you use it to power this device at an efficiency of %7. There must be easier ways to waste money than that.
Les LaZar
When I think of an "Artificial Leaf" I think of a device that uses sunlight as an energy source to crack water AND Carbon Dioxide into oxygen and a hydrocarbon...the hydrocarbon can later be combined with oxygen in the air to get energy as well as water and CO2.

This device is simply an electrolyzer. The O2 and H2 that it produces have to be collected, compressed and stored to be useful later in a fuel cell. The collection, compression and storage require more energy. While that energy could also come from solar panels, it is difficult to see how the entire process and capital investment would be superior to alternatives already available.

The main accomplishment I see is the solar cell component, which they claim is relatively inexpensive.
moreover
@ Captain Danger – Efficiency for renewable energy is not the be all, end all unlike power generation where you have to pay for fossil fuel AND equipment. For advanced experimental processes it's more important to identify the proper use case where this solution might be a better fit for reasons beyond efficiency. Also, Perovskites can be tuned to absorb light and produce power over more daytime hours.
The deerhunter
What about scaling the process up to produce and store useful large quantities? If it is only ever 6.7% efficient, then it is just a toy. The scaled up model would be what the world has been waiting for.
sam12
Apart from using the hydrogen when there are no sunlight, it can also be used to generate extra electricity during peak hours and also be harvested for hydrogen fuel cells vehicles, ships and planes.
For electric generation, there’s no need for complicated pumps and compressors. It’s splitting a liquid into gases, creating pressure to push into storage. When used to generate electricity, the fuel cells are turning hydrogen and oxygen into water, it will draw the gases as pressure will drop as they turned into liquid. It just needs some electronic wizardry and simple guidance pumps or valve systems.
As for efficiency, who cares, the solar energy beating down on earth is free and limitless. The crux is the cost of producing the energy and how feasible it is to scale.
kurt
reminds me of Daniel Nocera's work...

https://www.greenoptimistic.com/molybdenum-catalyst-hydrogen-20110414/