Nanoparticles digging the world's smallest tunnels

Jan 23, 2013
Graphite consists of layered carbon atoms. A metal particle bores into the graphite sample from the edges of these layers. Credit: KIT

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 the scientific journal Nature Communications.

The tunnels are manufactured applying nickel nanoparticles to graphite which then is heated in the presence of . The surface of the , 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 , 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 . "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 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.

Explore further: Transformations on carbon surfaces under the influence of metal nanoparticles and microwaves

More information: DOI: 10.1038/ncomms2399

Related Stories

New technique controls graphite to graphene transition

Jul 02, 2012

(Phys.org) -- University of Arkansas physicists have found a way to systematically study and control the transition of graphite, the “lead” found in pencils, to graphene, one of the strongest, lightest ...

Scientists shed light on magnetic mystery of graphite

Jan 26, 2012

The physical property of magnetism has historically been associated with metals such as iron, nickel and cobalt; however, graphite – an organic mineral made up of stacks of individual carbon sheets – has baffled ...

At the nanoscale, graphite can turn friction upside down

Oct 17, 2012

(Phys.org)—If you ease up on a pencil, does it slide more easily? Sure. But maybe not if the tip is sharpened down to nanoscale dimensions. A team of researchers at the National Institute of Standards and Technology (NIST) ...

Recommended for you

The simplest element: Turning hydrogen into 'graphene'

Dec 16, 2014

New work from Carnegie's Ivan Naumov and Russell Hemley delves into the chemistry underlying some surprising recent observations about hydrogen, and reveals remarkable parallels between hydrogen and graphene ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.