Facet-controlled synthesis and morphological evolution of Cu2O microcrystals

Cu2O microcrystals were prepared through reduction of Cu2+ ions by glucose in an alkaline aqueous solution. Various shapes of Cu2O microcrystals were obtained by adjusting the reaction temperature, NaOH concentration, and glucose amount. The morphology of the Cu2O crystals changed from pure octahedra to beveled cubes via corner-truncated octahedra and truncated cuboctahedra as the reaction temperature was increased. These changes arose because of the growth of the {100} and {110} facets at the expense of the {111} facet with increasing reaction temperature. The morphological evolution of Cu2O crystals from truncated cuboctahedra to corner-truncated octahedra via corner- and edge-truncated octahedra was observed with increasing NaOH concentration, which occurred because of the growth of {111} facets at the expense of {100} facets during simultaneous growth in the early stage and at the expense of {110} facets in the late stage. The morphological evolution of the Cu2O crystals from truncated cuboctahedra to pure cubes via beveled cubes and corner-truncated cubes was observed with increasing amount of d-(+)-glucose. The {110} and {111} facets were gradually replaced by {100} facets with increasing amount of d-(+)-glucose.