Synthesis and structural features of mesoporous NiO/TiO2 nanocomposites prepared by sol–gel method for photodegradation of methylene blue dye

A novel series of mesoporous NiO/TiO2 nanoparticles was successfully synthesized by sol–gel method using cetyltrimethylammonium bromide as controlling template in attempts to study the photodegradation of methylene blue dye. Structural and textural features of the composite samples were investigated by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherm, Fourier transformer infra-red (FTIR) and transmission electron microscope (TEM). The band energy gap of the samples was estimated using UV–vis spectrometer. A remarkable reduction in particle size to 4 nm and increasing the surface area up to 220 m2/g is detected upon increasing nickel oxide contents revealing the successful role of dopants in controlling the crystal growth and pore structure of the catalyst. Nearly complete mineralization of methylene blue dye occur significantly at higher rate over doped samples compared with pure titanium oxide. The degradation of the dye follows a pseudo first-order kinetics and the apparent rate constant increases with increasing the nickel oxide content up to 5 mol%. The exceptional photocatalytic activity of the samples was attributed to reduction in particle size, increasing in surface area, photoelectron/hole separation efficiency and the extension of the wavelength range of photoexcitation.

Photocatalytic degradation of methylene blue dye was successfully carried over Ni/TiO2. Embedded 5 mol% NiO compared with pure titania.Figure optionsDownload as PowerPoint slideHighlights
► Mesoporous NiO/TiO2 nanocomposites were successfully synthesized by sol–gel method.
► Design of particle structure by micelle template approach.
► The nanocomposites exhibit mesoporous structure with large surface area and nanoparticle size.
► The existence of nickel oxide is a prime factor in controlling nature of phase and particle size.
► Complete photocatalytic degradation of methylene blue dye was successfully carried over the nanocomposite samples.