Morphology-controlled Synthesis of Octahedral-to-Rhombic Dodecahedral Cu2O Microcrystals and Shape-dependent Antibacterial Activities

Morphology-controlled synthesis of cuprous oxide (Cu2O) microcrystal was achieved using a solvothermal method. The morphologies of the Cu2O microcrystals, namely octahedral, truncated octahedral, truncated rhombic dodecahedral, and rhombic dodecahedral, were fine-tuned by varying the oleylamine and sodium oleate concentrations. Only the {111} and {110} facets of the Cu2O microcrystals were involved in this morphological transition. Octahedral Cu2O microcrystals were obtained in the absence of oleylamine and at the highest sodium oleate concentration. Rhombic dodecahedral Cu2O microcrystals were obtained at the highest oleylamine concentration or at the lowest sodium oleate concentration. The rhombic dodecahedron, which exposed only the {110} facets, exhibited better antibacterial activities against Escherichia coli compared to the octahedron, which exposed only the {111} facets.