My watch list
my.chemeurope.com  
Login  

Nanoparticles digging the world’s smallest tunnels

25-Jan-2013

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

    Computer Simulation Discloses New Effect of Cavitation

    Researchers have discovered a so far unknown formation mechanism of cavitation bubbles by means of a model calculation. In the Science Advances journal, they describe how oil-repellent and oil-attracting surfaces influence a passing oil flow. Depending on the viscosity of the oil, a steam b ... more

    How metal clusters grow

    First the nucleus, then the shell: Researchers from Marburg and Karlsruhe have studied stepwise formation of metal clusters, smallest fractions of metals in molecular form. The shell gradually forms around the inner atom rather than by later inclusion of the central atom. Knowledge of all d ... more

    Smallest lattice structure worldwide

    KIT scientists now present the smallest lattice structure made by man. Its struts and braces are made of glassy carbon and are less than 1 µm long and 200 nm in diameter. They are smaller than comparable metamaterials by a factor of 5. The small dimension results in so far unreached ratios ... more

More about Rice University
  • News

    Brittle is better for making cement

    Because concrete, the world's most-used construction material, is such a major contributor to climate change, it's worth knowing every detail about how it's manufactured, according to Rice University scientists. The Rice lab of theoretical physicist Rouzbeh Shahsavari is looking into those ... more

    Battery components can take the heat

    Rice University materials scientists have introduced a combined electrolyte and separator for rechargeable lithium-ion batteries that supplies energy at usable voltages and in high temperatures. An essential part of the nonflammable, toothpaste-like composite is hexagonal boron nitride (h-B ... more

    Sweet technique finds cause of sour oil and gas

    In at least one -- and probably many -- oil and gas drilling operations, the use of biocides to prevent the souring of hydrocarbons wastes money and creates an unnecessary environmental burden, according to researchers at Rice University. The Rice lab of environmental engineer Pedro Alvarez ... more

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