Figure 3

SEM images of Cu ₂ O samples obtained with different concentrations of EDA. The concentrations of NaOH solution is 15 mol L⁻¹ and the concentrations of EDA were as follows: (a) 0 μL (EDA)/28 mL (total solution) (SI1-B1 in Additional file1), (b) 70 μL/28 mL (SI1-B2 in Additional file1), (c) 150 μL/28 mL (SI1-B3 in Additional file1), and (d) 300 μL/28 mL (SI1-B4 in Additional file1). The inset is the corresponding TEM morphology of the Cu₂O crystal.