Visible light photocatalytic activity of pure and palladium (Pd) doped SnO₂ nanoparticles by a one step facile route

In this paper, we report palladium (Pd) doping induced modifications in the structural, optical and photocatalytic behavior of SnO₂ nanoparticles. Powder X-ray diffraction and transmission electron microscope studies confirmed that both the pure and Pd doped SnO₂ (Pd: 0, 5, 10 wt%) crystallized in tetragonal rutile-type structure with spherical morphology. Furthermore crystallinity is reduced upon Pd doping. The crystallite size decreased from 42 to 35 nm and 31 for pure, 5 and 10 wt% Pd doped SnO₂ respectively. A noticeable red shift in the absorption edge was found and band gap narrowing in the range of 3.67–3.25 eV after doping by Pd. The photoluminescence emissions observed in the visible region are attributed to the defect levels rising due to oxygen vacancies. The photocatalytic activities of the pure and Pd doped SnO₂ samples were evaluated by the degradation of Methylene Blue (MB) Rhodamine B (RHB) in an aqueous solution under visible light irradiation. The photocatalytic activity and reusability of Pd (10 wt%) doped SnO₂ was much higher than that of the pure SnO₂. The improvement mechanism by Pd doping was also discussed.