Dr Keith McKenna of the Department of Physics at the University of York was part of a research team which discovered that the catalytic activity of nanoporous gold (NPG) originates from high concentrations of surface defects present within its complex three-dimensional structure. The research has the potential to assist in the development of more efficient and durable catalytic converters and fuel cells because nanoporous gold is a catalytic agent for oxidising carbon monoxide. The researcher created NPG by immersing an alloy of gold and silver in a chemical solution which removed the latter metal to create a porous atomic structure. Then, using transmission electron microscopy, they were able to detect evidence that the surface defects on the NPG were active sites for catalysis and the residual silver made them substantially more stable.


Dr McKenna, of the Department of Physics at the University of York, said: "Unlike gold nanoparticles, dealloyed NPG is unsupported so we are able to monitor its catalytic activity more accurately. We found that there are many surface defects present within the complex structure of NPG which are responsible for the high catalytic activity."


http://www.york.ac.uk/physics/


Takeshi Fujita, Pengfei Guan, Keith McKenna, Xingyou Lang, Akihiko Hirata, Ling Zhang, Tomoharu Tokunaga, Shigeo Arai, Yuta Yamamoto, Nobuo Tanaka, Yoshifumi Ishikawa, Naoki Asao, Yoshinori Yamamoto, Jonah Erlebacher & Mingwei Chen: Atomic origins of the high catalytic activity of nanoporous gold, In: Nature Materials AOP, August 12, 2012, DOI:10.1038/nmat3391: http://dx.doi.org/10.1038/nmat3391


Imitating the antennas of the silkmoth, Bombyx mori, to design a system for detecting explosives with unparalleled performance is the feat achieved by a team from the"Nanomatériaux pour Systèmes sous Sollicitations Extrêmes" unit (CNRS / Institut Franco-Allemand de Recherches de Saint-Louis), in collaboration with the Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse (CNRS / Université de Strasbourg).


Made up of a silicon microcantilever bearing nearly 500,000 aligned titanium dioxide nanotubes, this device is capable of detecting concentrations of trinitrotoluene (TNT) of around 800 ppq (parts per quadrillion, i.e. 800 molecules of explosive per 1015 molecules of air), thereby improving one thousand-fold the detection limit attainable until now. This innovative concept could also be used to detect drugs, toxic agents and traces of organic pollutants.


Image: Overall view of a microcantilever nanostructured by aligned titanium dioxide nanotubes. © Fabien Schnell/NS3E

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