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The team at the Centre for Computational Engineering and Sciences in Brazil extracted the material, which they called hematene, from ordinary iron ore. The material is described as two-dimensional because it is only three atoms thick, only slightly thicker than the much-hyped ‘wonder material’ graphene.
Hematene is a photocatalyst, meaning it increases the speed of chemical reactions when energised by light. This property makes it a prime candidate for photocatalytic water splitting, an artificial photosynthesis process which uses sunlight to convert water into hydrogen and oxygen.
A recent IMechE report called for more development of hydrogen as an energy source. As renewable power takes a bigger share of the market, excess energy must be stored, but lithium-ion batteries carry environmental risks. Hydrogen could generate electricity by powering turbines, be injected into the heating system or be used as low-emission fuel for cars.
“By widening our use of gas in the energy system, the UK will not be restricted to an electricity and battery future and will be able to adapt to a changing climate, emerging technologies, population and political demands,” said the report, led by Dr Jenifer Baxter, head of engineering at the IMechE.
Photocatalytic water splitting is a promising technique for hydrogen generation, but the process has not yet been commercialised. Hematene is more efficient than its precursor hematite, a well-known yet poorly-performing photocatalytic material.
The newly synthesised material absorbs visible light and generates negative and positive charges within a few atoms of its surface. Combining the material with titanium dioxide nanotube arrays also allowed more light to be absorbed. The light-generated electrons interact with the water molecules to generate hydrogen.
Hematene is a promising prospect for efficient hydrogen generation because hematite is one of the most common minerals on Earth and the main source of iron, which is the cheapest metal, said the researchers.
The work was funded by the Sao Paulo Research Foundation. The research appeared in Nature Nanotechnology.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.