New promising technologies were developed by Gubkin University and Louisiana Tech University as a result of joint research work
As a result of joint research project of Gubkin University and Louisiana Tech University, new methods to produce nanoparticles and nanoclusters of metals and their compounds inside the cavity of halloysite nanotubes are created.
In the 1950s, applying the new method of electron microscopy, the structure of a clay mineral from the group of kaolin – halloysite was discovered. It turned out that the most common form of the mineral was the shape of a multi-layered nanotube, which was formed when kaolin plates were rolled up. The halloysite structure can be imagined as a sheet of paper rolled up into a tube, the size of the inner diameter of which is about 20 nm, the outer diameter is about 50 nm, and the length of the tube varies from 400 nm to 2 microns. In such a way, a new natural nanostructured material was discovered by researchers, and is still actively studied in recent decades and may become the key to the development of nanotechnology on an industrial scale. Halloysite is mined in some regions of the world, including China, USA, New Zealand, Australia; the sites of halloysite are also known in Russia.
Gubkin University under the supervision of the Head of the Department of Physical and Colloid Chemistry Vladimir Vinokurov within the research project “Megagrant” and other related projects takes efforts to create new functional materials based on halloysite nanotubes. The main areas of research are the creation of catalysts for the oil and gas and petrochemical industries, as well as alternative energy, including photocatalysts; development of functional membranes; obtaining biologically active drugs, fluorescent materials; study of the properties of dispersed systems stabilized by halloysite nanotubes.
As a result of joint work, researchers from Gubkin University and Louisiana Tech University created methods which allow to produce nanoparticles and nanoclusters of metals and their compounds inside the cavity of halloysite nanotubes. The developed methods will make it possible to create nanoreactors for chemical processes with the size of the reaction space limited by the internal diameter of the tube. In recent tests of the obtained ruthenium catalysts, it was found that the hydrogenation reactions of aromatic compounds (benzene and its derivatives) proceed faster than in case of using industrial catalysts. Another advantage of the systems created is the stability of nanoparticles synthesized inside the cavity of nanotubes at high temperatures, allowing using catalysts in processes such as afterburning of combustor gases, as well as undergoing calcination and regeneration procedures of catalysts without losing their activity.
The research outcomes were highly appreciated by the international scientific community. In 2018, scientists received the award of one of the leading scientific journal – STAM, for the best article “Formation of metal clusters in halloysite clay nanotubes” (2017, Sci. Technol. Adv. Mater. 18 p.147).
Encapsulation of metal nanoparticles and their compounds inside the cavity of halloysite nanotubes is a promising technology that can be used to create antibacterial drugs, fluorescent tags, and other materials in which nanostructuring plays an important role.
