Sol–gel synthesis of Sn/Fe co-doped TiO2 nanoparticles: study of structural, optical and photocatalytic properties

Abstract

Titanium dioxide (TiO2) nanoparticles co-doped with tin and iron cations were synthesized using a simple sol–gel method with titanium(IV) tetra isopropoxide, tin(II) chloride dihydrate and iron(III) chloride hexahydrate as precursor materials. Different samples of Sn and Fe co-doped TiO2 nanoparticles (3, 5, 7 wt% Sn and 3, 5, 7 wt% Fe) were prepared. The effect of co-dopant on structural, optical, photocatalytic, and morphological properties of doped TiO2 nanoparticles were studied by X-ray diffraction (XRD), UV–Vis absorption spectroscopy, scanning electron microscopy, and transmission electron microscopy. Surface chemical state of nanoparticle was thoroughly examined by atomic X-ray photoelectron spectroscopy. XRD results showed the formation of TiO2 anatase phase in all samples. UV–Vis spectra showed that Sn/Fe co-doped TiO2 nanoparticles showed a decrease in the band gap energy (Eg) relative to undoped TiO2 sample. Thus, co-doped samples showed enhanced absorption at visible region and exhibited excellent photocatalytic activity for degradation of methylene blue solution under visible irradiation. 5 wt% Sn + 5 wt% Fe sample showed better photocatalytic activity than others samples.