Synthesis, characterization and photocatalytic H2 generation over ternary indium titanate nanoparticles.

A low temperature surfactant-free solution-phase method has been successfully developed for the synthesis of ternary In2TiO5, nanoparticles using a solvothermal route. The mechanistic aspects of synthesis of In2TiO5 nanoparticles from precursors, In(acac)3 and Ti(IV) isopropoxide in benzyl alcohol at 220 degrees C under solvothermal conditions, were investigated by GC-MS and 13C{1H} NMR analysis. The N2-BET surface area of the 5-8 nm sized In2TiO5 nanoparticles was found to be 60 m2 g(-1), which decreased with increase in calcination temperature; 38 m2 g(-1) at 800 degrees C; 5 m2 g(-1) at 1200 degrees C. The High resolution transmission electron microscopy (HR-TEM) shows well-developed lattice fringes of the crystalline nanoparticles, and selected area electron diffraction (SAED), pattern was indexed to be orthorhombic In2TiO5. The nanoparticles show better photocatalytic hydrogen generation from water-methanol mixtures over bulk In2TiO5, anatase TiO2 nanoparticles prepared by identical route and commercial TiO2 photocatalyst (Degussa, P25) under UV-visible irradiation (16% UV + 84% visible). Photocatalytic properties as a function of crystallinity and surface area of indium titanate nanoparticles have also been investigated. The high photoactivity obtained is correlated with the electronic and crystal structure of In2TiO5.