Corundum-type tubular and rod-like In2O3nanocrystals: synthesis from designed InOOH and application in photocatalysis

Abstract

Indium oxyhydroxide (InOOH) 1-D nanostructures have been synthesized utilizing the hexamethylene diamine (HMDA)-assisted hydrolysis of In³⁺ cation method in the solvent poly(ethylene glycol 400) (PEG-400). It was found that the amount of distilled water and the solvent type were two key factors for the synthesis of high quality nanocrystals. The anisotropic growth of InOOH could be attributed to the HMDA molecule-assisted oriented attachment of nanoparticles, and the formation of tubular InOOH nanostructures could be due to “dissolution and recrystallization”. By annealing InOOH precursors at 400 °C in air, hexagonal corundum-type indium sesquioxide (H-In₂O₃), which inherits the morphologies of its precursor with a slight size shrinking, was also prepared. The photocatalytic properties of tubular and rod-like H-In₂O₃nanocrystals were investigated by the photodegradation of rhodamine B (RhB) molecules under ultraviolet (UV) light irradiation.