Morphology tuning of inorganic nanomaterials grown by precipitation through control of electrolytic dissociation and supersaturation

The precise control of the morphology of inorganic materials during their synthesis is important yet challenging. Here we report that the morphology of a wide range of inorganic materials, grown by rapid precipitation from a metal cation solution, can be tuned during their crystallization from one- to three-dimensional (1D to 3D) structures without the need for capping agents or templates. This control is achieved by adjusting the balance between the electrolytic dissociation (α) of the reactants and the supersaturation (S) of the solutions. Low-α, weak electrolytes promoted the growth of anisotropic (1D and 2D) samples, with 1D materials favoured in particular at low S. In contrast, isotropic 3D polyhedral structures could only be prepared in the presence of strong electrolyte reactants (α ≈ 1) with low S. Using this strategy, a wide range of materials were prepared, including metal oxides, hydroxides, carbonates, molybdates, oxalates, phosphates, fluorides and iodate with a variety of morphologies.