Category Chemistry/Nanotechnology

Schematic of the pathway describing the evolution of adsorbed ethene (top left) to graphene (bottom left). The sequence of intermediates identified in the study and their respective appearance temperatures are indicated. Credit: F. Esch, R. Schaub, U. Landman

An international has developed a new way to produce single-layer graphene from a simple precursor: ethene aka ethylene – the smallest alkene molecule, which contains just two atoms of carbon. By heating the ethene in stages to a temperature of slightly >700C – hotter than had been attempted before – the researchers produced pure layers of graphene on a rhodium catalyst substrate. The stepwise heating and higher temperature overcame challenges in earlier efforts to produce graphene directly from hydrocarbon precursors.

Because of its l...

Scientists have developed a new molybdenum-coated catalyst that prevents an unwanted back reaction in certain chemical systems that split water into hydrogen and oxygen. (Andy Freeberg/SLAC National Accelerator Laboratory)

Hydrogen is one of the most promising clean fuels for use in cars, houses and portable generators. But water-splitting systems require a very efficient catalyst. Now an international research team, including scientists at DOE SLAC National Accelerator Laboratory, has developed a new catalyst with a molybdenum coating that prevents this problematic back reaction and works well in realistic operating conditions...

This image illustrates changes in photocurrent before and after exposure to UV light. Persistent photoconductivity is demonstrated even hours after the UV light has been turned off. This is illustrated by the pictograms showing charge carriers that come into contact with cells at the interface during in vitro experiments. Credit: Albena Ivanisevic

Researchers have developed a new approach for manipulating the behavior of cells on semiconductor materials, using light to alter the conductivity of the material itself. Albena Ivanisevic, a professor of materials science and engineering at NC Stat said: “Our work here effectively adds another tool to the toolbox for the development of new bioelectronic devices.” The new approach uses a phenomenon called persistent photoconductivity...

3-dimensional microstructures can be written using a laser, erased, and rewritten. Credit: KIT

3D printing by direct laser writing produces micrometer-sized structures with precisely defined properties. Researchers of Karlsruhe Institute of Technology (KIT) have now developed a method to erase the ink used for 3D printing. In this way, the small structures of up to 100 nm in size can be erased and rewritten repeatedly. This development opens up many new applications of 3D fabrication in biology or materials sciences, for instance.

Direct laser writing means that a computer-controlled, focused laser beam generates the structure in a photoresist similar to a pen...