A group of scientists has taken a major step towards creating a device that can collect water from the air and obtain hydrogen fuel powered entirely by solar energy. This way of generating energy has been a dream for researchers, and it looks like it’s coming.

Hydrogen fuel is an interesting energy vector that can contribute to ending the era of burning fossil fuels, which is leading the world to a catastrophic situation due to climate change, which has serious effects on terrestrial and marine ecosystems, but also on the socio-economic development of the country. world; migration and displacement; food security and the worsening of human diseases.

Although no method of energy production is harmless to the planet, it is clear that huge differences must prevail between them and the “cleanest” ones that come from renewable energies and, in the future, from nuclear fusion. Hydrogen fuel is not a direct part of renewable sources, but yes, they can be generated from them and it has one more essential feature: it can be stored.

Inspired by a plant leaf

Researchers from EPFL’s Optoelectronic Nanomaterials Molecular Engineering Laboratory, in collaboration with Toyota Motor Europe, have developed an ingenious system that combines semiconductor-based technology with new electrodes that have two key properties: they are porous to maximize contact with water in the air. ; and transparent to maximize exposure of the semiconductor coating to sunlight. When the device is exposed to sunlight, it takes water from the air and creates hydrogen gas.

The method is similar in concept to what nature itself does, where plants convert sunlight into chemical energy using carbon dioxide from the air. Other research groups have previously shown that it is possible to perform artificial photosynthesis generating hydrogen fuel from liquid water and sunlight using a device called a photoelectrochemical cell (PEC).

This technology can be adapted to collect moisture from the air, which led to these results. “The development of our prototype device was challenging because transparent electrodes for gas diffusion had not been demonstrated before and we had to develop new procedures for each step. However, because it is relatively simple and scalable, I believe our approach will open up new horizons for a wide range of applications from gas diffusion substrates to solar-powered hydrogen production.”they explain.

Technically, the process starts with a type of glass wool, which is essentially fibers of quartz (silicon oxide), and is processed into felt sheets by fusing the fibers together at high temperature. The wafer is then coated with a thin transparent film of fluorine-doped tin oxide, which is known for its excellent conductivity, robustness and ease of processing. The result is a transparent, porous and conductive sheet, necessary to maximize contact with water molecules in the air and allow photons to pass through. Finally, the wafer is again coated with a thin film of semiconductor materials that absorb sunlight.

Researchers acknowledge that the efficiency of converting the sun into hydrogen is modest and lower than for liquid cells. Efficiency is the driving force behind much of this research and investment in the underlying technologies to end dependence on fossil fuels. All this if the energy lobby, the most powerful on the planet, allows it, because part of the current situation stems from it.

Method and other information | SciTechDaily