Photocatalytic preparation of cuprous oxide crystals using a TiO2 catalyst

Abstract

Reddish cuprous oxide crystals can be readily formed by irradiating an aqueous alkaline Cu(II) solution containing suitable complexing agents with UV or sunlight in the presence of a photocatalyst such as TiO2 or ZnO. Various factors, including the Cu(II) concentration, pH of the Cu(II) solution, amount of TiO2 catalyst, method used to agitate the test suspension, concentration of potassium sodium tartarate, and intensity of UV radiation, affecting cuprous oxide preparations were investigated. Concentrations of Cu(II) and potassium sodium tartarate have no significant effect on reaction rates, while pH, and amount of TiO2, play important roles in the reaction. The dispersion of TiO2 in Cu(II) solution is another important factor. Cu(II) reduction rate is not affected as far as the amount of reduced Cu(II) plotted against the cumulative intensity of UV radiation is concerned. It is necessary to stop the cuprous oxide formation before the complete reduction of Cu(II), since metallic copper is formed on cuprous oxide.