Facile fabrication of ultrasmall and uniform copper nanoparticles

Ultrasmall and uniform copper nanoparticles were synthesized through a trace-level ethylenediaminetetraacetic acid (EDTA)-assisted wet chemical route in which Cu(OH)(2) colloid, KBH4 and polyvinyl pyrrolidone (PVP) were used as the Cu source, the reducing agent, and the protective agents, respectively. The copper nanoparticles exhibit a spherical morphology with a narrow size distribution, a uniform shape, and the average diameter of ca. 4 nm. The presence of trace EDTA is indispensable for the preparation of ultrasmall and uniform copper nanoparticles. EDTA concentration directly influences the copper nanoparticle size and uniformity. As EDTA concentration decreases, the size of the copper nanoparticles decreases, whereas the uniformity increases. The possible formation mechanism of ultrasmall and uniform copper nanoparticles was determined according to experimental results. (C) 2011 Elsevier B.V. All rights reserved.