The formation mechanism of nanosize copper-silver encapsulated in the inert carbon shell (CuAg@C) has been studied by in-situ small angle X-ray scattering (SAXS) spectroscopy. SAXS is a very useful method in studies of electron density distributions of nanoparticles. The in-situ synchrotron SAXS spectra have been determined during the temperature-dependent formation of the nanosize CuAg@C. A detailed structural changes corresponding to the growth of the CuAg nanoparticle during carbonization of Ag+-, Cu2+- and beta-cyclodextrin (beta-CD) complexes at the temperature range of 303-573 K is observed. By controlling the molar ratios of OH on beta-CD to metal (OH/M), the desired size (i.e., ranged from 7 to 40 nm) can be synthesized. Note that a characteristic transition temperature for the growth of the 14 nm CuAg(1:1)@C is found. A rapid growth of the CuAg nanoparticle occurs at 333-533 K. As expected, by TEM, the CuAg@C nanoparticles have a diameter of about 14 nm with the carbon shell thickness of about 3-5 nm.
Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2010: Advanced Materials, CNTs, Particles, Films and Composites
Published: June 21, 2010
Pages: 417 - 420
Industry sector: Advanced Materials & Manufacturing
Topics: Nanoparticle Synthesis & Applications