Path-breaking research takes Cusat duo to Nature

KOCHI: An international team of scientists led by Prof. M R Anantharaman and his PhD student Aravind Puthirath Balan of Department of Physics, Cochin University of Science and Technology along with scientists from University of Rice, Houston, USA, University of Houston, USA and others have extracted a three atom thick 2D material called ‘Hematene’, from a commonly occurring natural ore ‘Hematite’. This two-dimensional material derived from a non-van der Waals (non-layered) material hematite, the researchers said, could be a game changer for solar fuel generation.

This important finding is a major landmark in the realm of nano materials, since all other 2D materials which have been extracted so far are Van der Waals solids (layered materials), for eg: graphene. “2D materials from bulk precursors (non-van der Waals) having 3D bonding networks are rare, and in this context hematene assumes great significance,” said Prof Anantharaman. Hematene is an efficient photocatalyst, especially for hydrogen fuel generation by splitting water into hydrogen and oxygen capturing solar energy.  It could also serve as an ultra-thin magnetic material for applications in spintronic-based devices such as computers and other electronic equipment due to its ferromagnetic property, the researchers said.

Hematene photocatalysis is more efficient than hematite because photons generate negative and positive charges within a few atoms of the surface, the researchers said.  By pairing the new material with titanium dioxide nanotube arrays, which provide an easy pathway for electrons to leave the hematene, the scientists found they could allow more visible light to be absorbed. The researchers also discovered that hematene is ferromagnetic like a common magnet while hematite is anti-ferro magnet.  In ferro magnets, atoms’ magnetic moments point in the same direction whereas in anti ferro magnets, the moments in adjacent atoms alternate.

This investigation has been published in the latest issue of famed journal ‘Nature Nanotechnology’published on May 7, 2018. Along with Prof. M R Anantharaman and Aravind, from CUSAT as the lead investigators, Prof.Pulickal M Ajayan, Chair of Rice’s Department of Materials Science and Nano Engineering, the Benjamin M and Mary Greenwood Anderson Professor in Engineering and a Professor of Chemistry, also a native of Kodungallur and Chandrasekhar Tiwary, currently working as an assistant professor at the Indian Institute of Technology, Gandhinagar and others joined as the lead members from Rice University. Prof.Oommen Varghese of the Department of Physics, University of Houston along with his students are the other members of the team.