Nonaqueous sol-gel synthesis of a nanocrystalline InNbO₄ visible-light photocatalyst

A solution to nanocrystalline InNbO₄ as a photocatalytically active ternary metal oxide semiconductor was presented, which involved the reaction of two chemically different precursors. The reaction temperature was kept at 200°C and the photocatalysis was characterized by high crystallininty and a high surface area of 54 m²g^-1. The volume-weighted average crystallite size was calculated as 27.7 nm. Nitrogen sorption measurements were applied to determine the surface area of the InNbO₄nanoparticles. A type IV adsorption-desorption isotherm was found, which points to the existence of an interparticle porous structure. The results prove that simple solution routes can go beyond the common metal oxides generally synthesized on the nanometer-scale, and that they can be extended to functional materials traditionally prepared by high temperature, solid-state processes.