Preparation and reduction kinetics of uniform copper particles from copper(I) oxides with hydrogen

Uniform copper particles were prepared by reduction of copper(I) oxides with hydrogen at 69–111°C. Three types of precursor particles having average modal sizes of O.46, 0.62 and 1.26 μm, respectively were produced by reducing Fehling's solutions of different concentrations with glucose. The reduction of fine copper(I) oxide particles took place through an autocatalytic process, while the reaction rates of rather coarse oxide particles were controlled by the diffusion of gaseous species through the copper layers formed at a later stage of the process. The resulting copper particles retained the original morphology of the oxides. A moderately oxygen-rich layer about 30 Å thick was detected on exposure to air by means of photoelectron surface microanalysis (XPS).