A new breakthrough promised efficient hydrogen production from solar energy without using any platinum.

A major challenge is the use of the metal platinum as a co-catalyst when sunlight and water are used to produce hydrogen. The Earth’s reserves of platinum are limited, and extraction is associated with risks to both the environment and to human health. Moreover, the production is concentrated in only a few countries, for example South Africa and Russia.

Now a team led by Chalmers University of Technology, Sweden have created hydrogen gas using sunlight, water and tiny particles of electrically conductive plastic, making its production efficient, sustainable, at low cost and completely without platinum.

In a new study, published in the scientific journal Advanced Materials, a research team led by Professor Ergang Wang at Chalmers outline a new approach using advanced materials design of the electrically conductive plastic used in the process. This type of plastic, known as conjugated polymers, absorbs light efficiently, but is typically less compatible with water. By adjusting the material properties at the molecular level, the researchers made the material much more water compatible.

“With as little as one gramme of the polymer material, we can produce 30 litres of hydrogen in one hour”, explained Chalmers researcher Alexandre Holmes.

Furthermore, the electrically conductive plastic can also be produced without the use of harmful chemicals and in a much more cost-effective way. The next major step for Wang’s group will be to make the hydrogen process work using only sunlight and water, without any added helper chemicals. Currently, they use vitamin C, which acts as a so-called sacrificial antioxidant. By donating electrons, it prevents the reaction from stalling, which in the laboratory can show high hydrogen production rates.

To realise truly sustainable solar hydrogen, Professor Wang explains, the goal is to split water molecules into hydrogen and oxygen simultaneously, with sunlight and water as the only inputs.

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