Studies on formation mechanism of 3D Cu2O nanospheres through self-assembly of 0D nanodots. (August 2015) - Zhang, Lun
Graphical abstract: The growth mechanism of porous Cu2 O nanospheres was revealed successfully, which involved a self-assembly process from nanodots (0D) to nanosheets (2D) and nanospheres (3D). Highlights: Cu2 O crystals with average sizes ranging from 25 to 282 nm were synthesized. Concentration of PVP and acid ions has great influences on the final morphologies. Morphologies were less dependent on the concentration of NO3 − compared with Ac − . Self-assembly of Cu2 O crystals was observed through a route of 0D → 2D → 3D. Cu2 O nanospheres exhibit better adsorption ability toward MO than AC does. Abstract: Cu2 O crystals with different morphologies (solid and porous) and sizes (from 25 to 282 nm) were synthesized controllably through a facile solvothermal route. The growth mechanism was investigated by SEM and TEM with varying the concentration of poly (vinylpyrrolidone) (PVP, K30), CH3 COO − (Ac − ) and NO3 − acid ions in the precursor solution. The self-assembly of three types of Cu2 O nano-structures was observed through a general route of zero-dimensional (0D) → 2D → 3D. When Cu(Ac)2 ⋅H2 O was used as the copper sources, 0D Cu2 O nanodots with size of 2–7 nm were firstly assembled to 2D quasi-spherical and bookmark-like structures via Oriented attachment (OA), and then converted into 3D hierarchical Cu2 O nanoclusters (a few tens of nm) and porous sub-microspheres with an average size of 282 nm, respectively. While Cu(NO3 )2 ⋅3H2 O was used instead of Cu(Ac)2 ⋅H2 O, the similar assembly process occurred leading to the formation of Cu2 O porous nanospheres of 40–140 nm which exhibit better adsorption ability toward methyl orange compared with activated carbon. In addition, we also investigated the dependence of Cu2 O crystals on the concentration of acid ions (Ac − and NO3 − ). Compared with Ac −, the size and morphology of the obtained products were less dependent on the concentration of NO3 − acid ions. This study might provide a new insight into the growth mechanism of Cu2 O based micro- or nanostructures.