Figure 5

Photocatalytic activity of as-obtained Cu ₂ O products under visible light. (a) Plots of concentration ratios of MO in an aqueous solution against given irradiation intervals in the presence or absence of Cu₂O products for samples S1 to S4, which depicted the synthesis conditions as listed in Table 1. (b) The plots of ln(C/C ₀) versus time of MO degradation in presence of Cu₂O products, without H₂O₂.