Star Trek-style device harvests water from thin air

By Mark Waghorn via SWNS

A Star Trek-style device that harvests water from thin air to provide hydrogen fuel has been developed by scientists.

The solar-powered system opens the door to cheap green gasoline, diesel and kerosene used for air travel.

Principal investigator Professor Kevin Sivula of the Swiss Federal Institute of Technology, Lausanne said: "To realize a sustainable society, we need ways to store renewable energy as chemicals that can be used as fuels and feedstocks in industry.

"Solar energy is the most abundant form of renewable energy, and we are striving to develop economically-competitive ways to produce solar fuels."

(Alain HERZOG 1006 LAUSANNE via SWNS)

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Zero carbon hydrogen yields only water when used in fuel cells. But it is not abundant in nature. Large-scale production usually involves fossil fuels.

The international team was inspired by leaves. They convert sunlight into energy using carbon dioxide from the air.

A plant transforms the molecules into sugars and starches, which it stores - a process known as photosynthesis.

The prototype acts like an artificial leaf. It has a semi-conductor and electrodes that are porous - maximizing contact with humidity.

A transparent coating boosts exposure to sunlight - taking water from the air and turning it into gas.

Instead of building traditional opaque layers, the substrate is a 3-D mesh of felted glass fibers.

Lead author Dr. Marina Caretti said: "Developing our prototype device was challenging since transparent gas-diffusion electrodes have not been previously demonstrated, and we had to develop new procedures for each step.

"However, since each step is relatively simple and scalable, I think our approach will open new horizons for a wide range of applications starting from gas diffusion substrates for solar-driven hydrogen production."

The researchers began with a type of glass wool, which is essentially quartz or silicon oxide fibers. They processed it into felt by fusing them together at high temperatures.

The wafer is coated with a transparent thin film of fluorine-doped tin oxide, known for its excellent conductivity, robustness and ease to scale-up.

It is ideal for letting light particles known as photons through. The wafer is further smothered with a thin-film of sunlight-absorbing semiconductor materials.

It still lets light through but appears opaque due to the large surface area of the porous substrate. It can already produce hydrogen fuel once exposed to sunlight.

The scientists went on to build a small chamber containing the coated wafer, as well as a membrane for separating the produced hydrogen gas for measurement.

When their chamber is exposed to sunlight under humid conditions, hydrogen gas is produced, achieving what the scientists set out to do.

Sivula said: "It shows the concept of a transparent gas-diffusion electrode for solar-powered hydrogen gas production can be achieved."

A project named "Sun-to-X" is dedicated to advancing the technology described in Advanced Materials.

It could accomplish some of what 'The Replicator' does in Star Trek by providing an endless supply of cheap fuel.