Designing of Copper Nanoparticle Size Formed via Aerosol Pyrolysis
- PDF / 770,968 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 54 Downloads / 239 Views
CTION
TODAY, submicron and micron particles of copper are industrially produced either from copper sulfate solutions by electrolytic recovery[1] or by hydrogen reduction under high pressure in an autoclave.[2] In the hydrocopper process, copper sulfate is reduced by hydrogen at a temperature of 448 K (175 C) and pressure of 25 bar.[2] Previous experimental and theoretical studies have shown very good mechanical and catalytic properties of so-obtained nanostructured copper powders,[3] which in many applications, as shown elsewhere, are vastly superior to bulk copper materials. This probably results from their fine grain size and enhanced specific surface areas. There are, of course, some drawbacks related to difficulties in preparation of powders without thin oxide layers, which are frequently formed immediately after their exposure to air, even in the cases of very low concentrations of oxygen during powder fabrication. The application of copper nanoparticles of diameters in the range 0.1 to 1000 nm in preparation of drugs for delaying senility and treating cerebral ischemia and cerebral thrombus squeal is well known. Its main advantages are a curative effect and high levels of safety. The use of copper in interconnection of integrated circuits is one example of amazing copper applications in nanotechnology. Today, the dominant VUKOMAN JOKANOVIC´, Research Professor, and BOZˇANA CˇOLOVIC´, Research Associate, are with the Institute of Nuclear Sciences ‘‘Vincˇa’’, University of Belgrade, 11001 Belgrade, Serbia. Contact e-mail: [email protected] SREC´KO STOPIC´ and BERND FRIEDRICH, Research Professors, are with the IME Process Metallurgy and Metal Recycling, RWTH Aachen University, 57410 Aachen, Germany. Manuscript submitted October 27, 2008. Article published online May 31, 2012 METALLURGICAL AND MATERIALS TRANSACTIONS A
application of copper nanopowders is in catalysis. Although gold nanoparticles show the highest catalytic activity, the advantages of nanocopper are significant; its reactivity is similar to that of nanogold and its price is much lower. Chemical reactions catalyzed by fine copper powders, such as copper powders obtained by ultrasonic spray pyrolysis, exhibit faster kinetics and can be carried out at temperatures lower than those when coarse powders are used. Copper nanoparticles can be used in organic synthesis reactions, like the oxidation of phenol with molecular oxygen,[4] oxidation of alkanethiols,[5] coupling of epoxyalkylhalides,[6] and in the Ullmann reaction.[7] Also, the Cu nanoparticles enhance the catalytic activity and selectivity of ZnO in hydration, dehydration, and hydrogenation reactions in methanol synthesis.[8] The ultrasonic spray pyrolysis (USP) is an innovative, powerful tool for the synthesis of particles of various materials with controlled and narrow particle size distribution.[9–12] The process also enables very efficient powder morphology control and the use of relatively cheap precursors. The precursors also have great potential as efficient solutions for the synthesis of various met
Data Loading...
