Structural, optical and photocatalytic properties of TiO2/SnO2 and SnO2/TiO2 core-shell nanocomposites: An experimental and DFT investigation

•TiO2/SnO2 shows highest visible light absorption in the UV/Visible spectra.•Quenching of peaks in core/shell nanocomposites compared to bare nanoparticles.•Density functional study shows that TiO2/SnO2 structure with oxygen vacancy is semi metallic in nature.•Better photocatalytic activity by TiO2/SnO2 structure than the other three samples.

We employed an efficient and cost effective method to synthesize core-shell TiO2/SnO2 and inverted core-shell SnO2/TiO2 nanocomposites and investigated their visible light photo catalytic activity for degradation of dye methyl orange. We carried out techniques such as XRD and TEM for the structural verification while UV-Visible and photoluminescence spectra for the optical characterization. BET is done to reveal pore diameter and surface area of prepared nanosystems. We have also performed DFT based calculation using VASP 5.2 to calculate density of states. The analyses of density of states indicate a higher photocatalytic efficiency of core-shell TiO2/SnO2 nanostructures and which we indeed observe through experiment as well.

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