A next-generation reactor could transform water and sunlight into clean fuel.
The idea is based on a natural but complex process: the separation of water molecules into oxygen and hydrogen, using photocatalysts. The latter, exposed to light, initiate chemical reactions which release hydrogen, a key energy resource. However, existing systems struggle to achieve sufficient efficiency for operation at large scale.
In detail, the prototype developed is based on the use of photocatalytic sheets capable of capturing solar energy to decompose water molecules. Unlike conventional systems, this reactor uses a two-stage configuration, known as Z-shaped, which effectively separates oxygen and hydrogen.
This approach not only improves the efficiency of the process, but also reduces the risks associated with the formation of explosive gases like oxyhydrogen. Using this method, the researchers were able to demonstrate almost perfect energy conversion under ultraviolet light, an important milestone for photocatalyst optimization.
The team designed a 100 m² reactor capable of operating outdoors with natural light, proving the feasibility of large-scale deployment. This device incorporates advanced safety measures to manage potentially hazardous byproducts, while allowing direct separation of hydrogen and oxygen. This configuration promises a safer and more sustainable solution for hydrogen production.
Furthermore, the development of photocatalysts sensitive to visible light remains a priority, as it would make it possible to exploit a larger part of the solar spectrum and further improve overall efficiency.
According to Professor Kazunari Domen, this advance could transform the conversion of solar energy into storable chemical energy, provided that catalysts are improved. Currently, their efficiency barely reaches 5% in real conditions. Researchers also emphasize the role of public policies. A notable breakthrough in this technology would encourage governments and businesses to invest in this type of infrastructure and revise regulations around solar fuels.
Beyond technology, the ecological potential is immense. A clean, renewable fuel accessible at scale could significantly reduce our dependence on fossil fuels, marking a crucial step towards a sustainable energy transition. This discovery shows that there is still a long way to go before commercial adoption. But the first steps are promising and the commitment of scientists could well open the way to a greener energy future.
What is photocatalysis and why is it key for hydrogen?
Photocatalysis is a chemical reaction accelerated by a catalyst activated by light, often the Soleil. It is essential for breaking down molecules like water into its basic elements: hydrogen and oxygen.
Photocatalysts absorb light energy, exciting their electrons to initiate the reaction. These energized electrons then help break the chemical bonds in the water.
In the quest for a clean fuel, this process makes it possible to produce hydrogen without CO₂ emissions. Its theoretical simplicity, however, masks practical problems: it requires high-performance materials and efficient systems.
