pH-Control as a way to fine-tune the Cu/Cu2O ratio in radiation induced synthesis of Cu2O particles

Abstract

In this work we have optimized the γ-radiation induced synthesis of Cu–Cu₂O particles from aqueous CuSO₄ solution by investigating the effect of pH. The obtained precipitate was analyzed by XRD and SEM techniques. The results indicated that at solution pH lower than 3.75, quasi-spherical Cu agglomerates can be formed while at pH higher than 4.40 only octahedron-shaped Cu₂O particles are produced. At solution pH in the range from 3.75 to 4.40, a Cu–Cu₂O mixture is produced. It was found that the relative amount of Cu₂O in the Cu–Cu₂O precipitate increases with pH in the studied range. The influence of solution pH on the Cu/Cu₂O ratios in the product can be explained on the basis of pH-dependent competition kinetics between the reactions leading to either Cu or Cu₂O formation. As a consequence, the composition and morphology of the Cu–Cu₂O precipitate can be tuned by controlling pH of the aqueous CuSO₄ solution during the γ-radiation induced synthesis.