My watch list  

Nanoparticles digging the world’s smallest tunnels


The world’s smallest tunnels have a width of a few nanometers only. Researchers from Karlsruhe Institute of Technology (KIT) and Rice University, USA, have dug such tunnels into graphite samples. This will allow structuring of the interior of materials through self-organization in the nanometer range and tailoring of nanoporous graphite for applications in medicine and battery technology. Results are now presented in Nature Communications.

The tunnels are manufactured applying nickel nanoparticles to graphite which then is heated in the presence of hydrogen gas. The surface of the metal particles, that measure a few nanometers only, serves as a catalyst removing the carbon atoms of the graphite and converting them by means of hydrogen into the gas methane. Through capillary forces, the nickel particle is drawn into the “hole” that forms and bores through the material. The size of the tunnels obtained in the experiments was in the range of 1 to 50 nanometers, which about corresponds to one thousandth of the diameter of a human hair.

To furnish proof of the real existence of these graphite tunnels, the researchers have made use of scanning electron and scanning tunneling microscopy. “Microscopes, in fact, image only the upper layers of the sample,” the principal authors of the study, Maya Lukas and Velimir Meded from KIT’s Institute of Nanotechnology, explain. “The tunnels below these upper layers, however, leave atomic structures on the surface whose courses can be traced and which can be assigned to the nanotunnels by means of the very detailed scanning tunneling microscopy images and based on computerized simulations.” In addition, the depth of the tunnels was determined precisely by means of a series of images taken by a scanning electron microscope from different perspectives.

Porous graphite is used, for example, in the electrodes of lithium ion batteries. The charge time could be reduced using materials with appropriate pore sizes. In medicine, porous graphite could serve as a carrier of drugs to be released over longer periods of time. Replacing graphite by nonconductive materials, e.g. boron nitride,  with atomic structures similar to that of graphite,  the tunnels could serve as basic structures for nanoelectronic components such as novel sensors or solar cells.

Facts, background information, dossiers
  • Rice University
  • Karlsruher Institut…
More about KIT
  • News

    3-D-printing of glass now possible

    Glass is one of mankind's oldest materials. It was used as far back as in ancient Egypt and ancient Rome and has found a place now also in manufacturing technology of the 21st century. An interdisciplinary team at the KIT led by mechanical engineer Dr. Bastian E. Rapp developed a process us ... more

    Metal-organic frameworks used as looms

    Researchers of Karlsruhe Institute of Technology (KIT) have made major progress in the production of two-dimensional polymer-based materials. To produce cloths from monomolecular threads, the scientists used SURMOFs, i.e. surface-mounted metal-organic frameworks, developed by KIT. They inse ... more

    Cloud Formation: How Feldspar Acts as Ice Nucleus

    In the atmosphere, feldspar particles act as ice nuclei that make ice crystals grow in clouds and enable precipitation. The reason was found by researchers of Karlsruhe Institute of Technology (KIT) and University College London (UCL) with the help of electron microscopy observations and mo ... more

More about Rice University
  • News

    Boron nitride foam soaks up carbon dioxide

    Rice University materials scientists have created a light foam from two-dimensional sheets of hexagonal-boron nitride (h-BN) that absorbs carbon dioxide. They discovered freeze-drying h-BN turned it into a macro-scale foam that disintegrates in liquids. But adding a bit of polyvinyl alcohol ... more

    Technique enables printable and rewritable color images

    A chemical process that allows color images to be printed on specially coated paper and then erased so that different images can be printed on the same paper has been developed by researchers at Rice, Yonsei and Korea universities. The technique makes use of structural colors, which have di ... more

    Laser-induced graphene made from wood

    Rice University scientists have made wood into an electrical conductor by turning its surface into graphene. Rice chemist James Tour and his colleagues used a laser to blacken a thin film pattern onto a block of pine. The pattern is laser-induced graphene (LIG), a form of the atom-thin carb ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE