Synthesis and Enhanced Solar Light Photocatalytic Activity of a C/N Co-Doped TiO2/Diatomite Composite with Exposed (001) Facets

Abstract

A C/N co-doped TiO2/diatomite composite with exposed (001) facet was prepared through a facile sol–gel method using tetrabutyl titanate as a titanium precursor and hexamethylenetetramine as C/N dopant. The as-prepared photocatalyst composites were characterised by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS), photoluminescence spectroscopy (PL), as well as X-ray photoelectron spectroscopy (XPS). The TiO2 nanoparticles were immobilised and uniformly distributed on the surface of diatomite with a smaller grain size compared with pure TiO2. In addition, compared with pure TiO2 and the undoped TiO2/diatomite composite, the photocatalytic activity of the C/N co-doped TiO2/diatomite composite under solar light illumination was obviously enhanced. Results indicate that the introduction of a C/N dopant can effectively promote the growth of the highly active anatase (001) facet of TiO2. On the other hand, the N impurity was doped into the interstitial spaces of the TiO2 lattice, which accelerated the charge transfer and hindered the recombination of photogenerated electron–hole pairs. The results show that the as-prepared composite exhibited promising applications in dye wastewater degradation owing to its outstanding reusability and cost-effectiveness.