Sol–gel synthesized TiO2–CeO2 nanocomposite: an efficient photocatalyst for degradation of methyl orange under sunlight

The nanocomposites of TiO2–CeO2 are synthesized by a simple and cost-effective sol–gel method with cetyl trimethyl ammonium bromide (cationic surfactant) as capping agent at 500 °C. The X-ray diffraction analysis revealed phase purity of synthesized product. The X-ray photoelectron spectroscopy showed Ti4+ oxidation state of Ti element while Ce element was exist as a mixture of Ce3+ and Ce4+ oxidation state. The UV–Vis diffuse reflectance spectra clearly indicate the positive alteration in the optical response of TiO2 nanoparticles by the introduction of CeO2 nanoparticles. Scanning electron microscopic study revealed the formation of nanoclusters of spherical particles with uniform size distribution. Energy dispersive X-ray analysis confirmed the elemental composition. Fourier transform infrared spectroscopy analysis confirmed the presence of Ti–O–Ti stretching modes in the range of 900–400 cm−1. Photoluminescence spectroscopy was used to study the rate of recombination and transfer behaviors of photoexcited electron–hole pairs in the nanocomposites. Further, the photocatalytic activity of pure TiO2 nanoparticles and nanocomposite of TiO2 was studied using methyl orange. The TiO2:CeO2 nanocomposites exhibit high dye degradation compare with pure TiO2 nanoparticles. The composite TiO2:CeO2 (7:3) shows highest photocatalytic degradation of methyl orange dye in UV (60 min) and sunlight (90 min).