A novel and facile method to synthesize self-assembled BiOI microrings composed of nanoplatelets

Self-assembled BiOI microrings composed of nanoplatelets have been successfully fabricated via a simple hydrothermal method using an oleic acid contained solvent as a reaction medium. For a comparison, only BiOI microplatelets were obtained without oleic acid. Oleic acid acts critically as a trigger for the assembly of microrings through an interaction between carboxylate anion and Bi3+ ion (3COO−-Bi3+). The complex (3COO−-Bi3+) adsorbed onto the planes of BiOI nuclei, controlling the orientated crystal growth, and the microrings formed through a self-assembly of nanoplatelets. The photocatalytic activity of the obtained BiOI microrings was found to be about 30% higher than that of microplatelets. The novel way may also be extended to preparation of a wide range of self-assembled microrings composed of nanoplatelets.