Title: Synthesis and characterization of TiO2/SnS2 core-shell nanostructures.
Recent breakthrough in nanotechnology for energy related applications require the use of complex structures with controlled morphology as well as heterostructures combining different compounds.Thus, higher conductivity, better chemical stability,improved photovoltaic and photocatalytic performance can be achieved. Fabrication of core-shell nano heterostructures has become avery active research topic in the recentyears.Basically, Type-ii) core- shell structures have both valence and conduction bands in the core lower (or higher) than those in the shell,as a result of which one carrier is confined to the core and other to the shell, in addition to allowing access to wavelengths that would otherwise not be possible with a single material. In the present study, TiO2/SnS2 core-shell nanostructureswith TiO2 as the core and SnS2 as the shell have been synthesised by a single-step hydrothermal method followed by calcination in either an oxidising atmosphere (labelled as CS1) or in Ar atmosphere (labelled as CS2). HRTEM studies revealedthe formation of core-shell nanorods with rutile as well as defective Ti3O5 as core in case of CS2 whichwas found to be rich in oxygen vacancies and had a lower band gap. Raman studies showed considerable peak shift of rutile TiO2 for CS2 compared to CS1 due to the presence of oxygen vacancies.