Preparation, electrocatalytic and photocatalytic performances of nanoscaled CuO/Co3O4 composite oxides

Cu-Co composite oxides with different Cu/Co atomic ratios were prepared by the calcination of the precursors synthesized via a co-precipitation method. The samples were characterized by XRD, SEM and TEM, respectively. The XRD analysis revealed that only spinel structure of Cu-Co composite oxide was confirmed with lower Cu/Co ratio (<1:2). The sizes and morphologies of samples are controlled significantly by the Cu/Co atomic ratios. The electrocatalytic activity for p-nitrophenol reduction in a basic solution with the samples decorated on glassy carbon (GC) electrodes was tested by cyclic voltammetry (CV). The results showed that the sample with Cu/Co ratio of 2:8 exhibited the highest catalytic activity for p-nitrophenol reduction. The photocatalytic performances of the samples for the degradation of methyl orange under irradiation of visible light were investigated. The samples with Cu/Co ratios from 5:5 to 10:0 all showed better photocatalytic activities for methyl orange degradation, but the sample with Cu/Co ratio of 9:1 exhibited much higher catalytic activity. The catalyst with Cu/Co ratio of 9:1 also exhibited excellent repeatability for the catalytic degradation of methyl orange.