Submicron Cu particles were prepared by reducing Cu2+ ions with ascorbic acid via liquid phase reduction method. The oxidation potential of ascorbic acid (C6H8O6) was measured to evaluate the feasibility of the redox reaction at different pH. Ascorbic acid was able to reduce the Cu2+ to Cu particles when the solution pH varied between 3 and 7. The effects of the reaction parameters, including the solution pH, the concentration of PVP (polyvinylpyrrolidone) and Cu2+, on the preparation of Cu particles were also investigated. The reaction path varied with the solution pH. Cu particles could be directly reduced from Cu2+ at pH 3, whereas they are reduced through Cu2O at pH 5 or 7. PVP was effective in inhibiting the agglomeration of Cu particles through steric effect. (C) 2013 Elsevier B.V. All rights reserved.