(307d) Large-Scale Production of Carbon-Coated Copper Nanoparticles for Sensor Applications

Copper nanoparticles have attracted considerable interest because of their optical, catalytic, mechanical and electrical properties, resulting in a wide range of applications in the field of metallurgy, catalysis, nano- and optoelectronics.

Here, we use reducing flame spray synthesis for the large-scale production of 1 nm carbon coated metallic copper nanoparticles (10 to 20 nm).[1] The carbon coating protected the zero-valent copper particles from oxidation in air. Raman Spectroscopy and solid state 13C magic angle spinning revealed that the carbon layers consisted of a sp2 – hybridized carbon modification in the form of graphene stacks.

Bulk pills of pressed carbon/copper nanoparticles displayed a highly pressure- and temperature dependent electrical resistivity. The negative temperature coefficient (NTC) behavior of the material revealed a similar or greater material constant (beta= 4550 K) than commercial sensing materials. These properties suggest the use of the carbon/copper nanocomposite as novel, low cost temperature sensing material and offer a metal-based alternative to the currently used brittle oxide based spinels and perovskites.

[1] E. K. Athanassiou, R. N. Grass, W. J. Stark,. Nanotechnology, 17, 1668-1673 (2006)

Fig. 1: Transmission electron micrograph of as prepared (left), etched with HNO3 C/Cu nanocomposite (middle) and the temperature dependence of the resistivity (right) under two experimental conditions (T1, high pressure and T2, ambient pressure (inset)).