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Meet the hematene, the “iron graphene”, promising for solar energy generation

A nanomaterial with specific characteristics has been achieved from iron ore by CCES reserachers in collaboration with institutes from the USA, India and Germany

Driven by studies with graphene, researchers from the Center for Computational Engineering & Sciences (CCES) developed the hematene, a bidimentional material as thick as a few atomic layers (nanometers), from iron ore, more specifically from hematite (Fe2O3). Physicists Douglas Soares Galvão and Cristiano Woellner collaborated with researchers based in the US, India and Germany to obtain 2D materials from abundant and cheap 3D sources, such as iron ore. The reasearch was published by Nature Nanotechnology.

The hematene was obteined by liquid exfoliation, in the Department of Materials Science and NanoEngineering, Rice University, in Huston/TX, USA. In this process, the hematite was submitted to sonication (application of sound waves), centrifugation and vacuum filtration. These procedures are necessary for the hematite to be able to be manipulated in solution and have its iron and oxygen atoms rearrenged to form the nanomaterial.

In addition to having a stable structure, the hematene presented potential for photocatalysys. In other words, it is capable of absorbing natural light, converting it into electricity and allowing electrons to flow on the surface without dissipation, which makes this new material a promising ingredient to the composition of photovoltaic cells – that capture sunlight to generate eletric power. Associating the hematene to titanium dioxide nanotubes may also increase its ability to absorb natural light, allowing greater energy generation.

Transforming the hematite in hematene also changes the magnetic properties of the new compound when compared to its origin. While the hematite is not ferromagnetic, the hematene shows magnet-like characterictics, thanks to the alignment of the iron and oxygen atoms. “At first, this could be useful in spintronic applications, data storage, and magnetic sensing”, illustrates Galvão.

Another uncommon hematene characteristic is that it is not obtained from lamellar solids – stabilized by van der Waals forces – unlike the graphene. That is to say that the hematene is a 2D structure obtained from a non-lamellar 3D structure. This property has gotten the researchers’ attention to explore other non-van der Waals minerals as feedstock to new 2D materials.

“Up until now, nearly all 2D materials were obtained from lamellar structures. The hematene was obtained from the hematite – non-lamellar 3D – which is a groundbraking approach”, describes Galvão. “At first there was no guarantee that by ‘slicing’ a 3D material we could get stable 2D structures. There are hundreds of materials such as the hematite with potential to generate new nanomaterials. We are looking into which other materials could be good candidates to doing so (pontetially using Artificial Intelligence methods, such as machine learning)”, concludes the author.

 

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