2D Material Revolutionizes Solar Fuel Generation

Following the isolation of graphene in 2004, a race began to synthesize new two-dimensional materials. 2D materials are single-layer substances with a thickness of between one atom and a few nanometers (billionths of a meter). They have unique properties linked to their reduced dimensionality and play a key role in the development of nanotechnology and nanoengineering.

An international group of researchers including Brazilian scientists affiliated with the University of Campinas (UNICAMP) have succeeded in producing a new material with these characteristics.

The researchers extracted a 2D material they call hematene from ordinary iron ore like that mined in many parts of the world, including Brazil. The material is only three atoms thick and is thought to have enhanced photocatalytic properties.

International group of researchers including Brazilian scientists obtain new material from iron ore with application as a photocatalyst

The research was conducted at the Center for Computational Engineering and Sciences (CCES), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP, and during a research internship abroad that was also supported by FAPESP via a specific scholarship.

Douglas Soares Galvão, a researcher at CCES and one of the authors of the study, told Agência FAPESP about the discovery. “The material we synthesized can act as a photocatalyst to split water into hydrogen and oxygen, so that electricity can be generated from hydrogen, for example, as well as having several other potential applications,” he said.

The new material was exfoliated from hematite, one of the most common minerals on earth and the main source of iron, which is the cheapest metal, used in many products and above all to make steel.

Unlike carbon and its 2D form graphene, hematite is a non-van der Waals material, meaning it is held together by 3D bonding networks rather than by nonchemical and comparatively weaker atomic van der Waals interactions, which are noncovalent (they do not involve the sharing of one or more pairs of electrons by the atoms that participate in the bond).

Because it is a naturally occurring mineral, has highly oriented, large crystals and is a non-van der Waals material, the researchers believe that hematite is an excellent precursor for the exfoliation of novel 2D materials.

Most of the 2D materials synthesized to date were derived from samples of van der Waals solids. Non-van der Waals 2D materials with highly ordered atomic layers and large grains are still rare,” Galvão said.

Hematene was synthesized by the liquid-phase exfoliation of hematite ore in an organic solvent, N,N-dimethylformamide (DMF). Transmission electron microscopy confirmed the exfoliation and formation of hematene in single sheets with a thickness of only three iron and oxygen atoms (monolayer) and in randomly stacked sheets (bilayer).

The innovation is described in an article published in Nature Nanotechnology.

Source: http://agencia.fapesp.br/