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

Abstract

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 °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 m²g^-1, which decreased with increase in calcination temperature; 38 m²g^-1 at 800 °C; 5 m²g^-1 at 1200 °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.