Control of CuO Particle Size on SiO₂ by Spin Coating

Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to study the size and distribution of nanometer-sized metallic particles of four Cu/SiO 2 model catalyst systems. The systems were constructed by spin coating copper(II) acetate [Cu(CH 3 CO 2 ) 2 ·H 2 O, Cu(ac) 2 ] solutions of varying concentration (0.0040, 0.0070, 0.0085, and 0.010 M) onto polished Si(100) substrates with an 5−10 nm SiO 2 oxide overlayer. Homogeneously distributed, nanometer-sized CuO particles were formed by calcinating the samples to 450 °C for 4 h. Narrow particle size distributions were observed for each system, with mean particle size increasing with increasing concentration. The ability to control mean particle size to the order of 1 nm was successfully demonstrated over this concentration range.