Hydroxyl ions: flexible tailoring of Cu 2 O crystal morphology.

The precise control architectures of Cu 2 O crystals are very crucial, which have a significant influence on their various performances. Herein, Cu 2 O crystals with diverse architectures were achieved via finely adjusting the concentration of NaOH. The intriguing results showed that the addition of specific amounts of OH - to the solution was crucial to tailor the morphology and size of the resulting microcrystals. We observed the evolution of the shapes of the Cu 2 O microcrystals, which change from a rhombic dodecahedron to spherical, octahedral-like and then to hexapod upon the increase in the NaOH concentration. Adjusting the volume of NaOH added provides a means to vary the particle size. Furthermore, density functional theory (DFT) may reveal that OH - ions serve as an efficient coordination agent selectively adsorbing onto different crystal faces of Cu 2 O crystals modifying the crystal energies, inducing the structure anisotropy on crystal growth. This work reveals that an effective and facile strategy has been developed for morphology-control of Cu 2 O crystals.