Two-dimensional (2D) CuO layered oval nanosheets and three-dimensional (3D) nanoellipsoids were grown on a large scale at ∼65 °C by a facile template-free method. Shape and dimensionality control of well-defined CuO single crystals could be achieved by simple variations of pH value. At pH 8.5, CuO nanosheets were obtained, whereas at pH 7.5, CuO nanoellipsoids were formed. XRD, SEM, TEM, and HRTEM were used to characterize the products. The growth mechanisms were discussed by monitoring the early growth stages. It was shown that the CuO nanoa...
