Effect of calcination atmosphere on the structure and photocatalytic properties of titania mesoporous powder

In the work presented here, mesoporous titania (MTO) powders are synthesised by the sol?Cgel method using amphiphilic triblock copolymer as a template in two different calcination atmospheres, N₂ and air. Various techniques such as sequential thermal analysis (STA), small-angle X-ray diffraction (SAXRD), wide-angle X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet (UV)?Cvisible spectroscopy, high-resolution transmission electron microscopy (HRTEM) and N₂-adsorption/desorption analysis were utilised to study the prepared samples. Furthermore, the photocatalytic activities of the prepared samples were evaluated from the photo-degradation analysis of methylene blue (MB). For the sample calcined at N₂, the formation of an ordered mesostructure with a high specific surface area (172?m²?g^?1), mesoporosity (48%) and enhanced photocatalytic activity were obtained compared to that of the sample calcined in air. The observed increased MB degradation for the latter is mainly attributed to the formation of higher specific surface area and mesoporosity. The availability of highly ordered open-pore channels could provide increased contacts between reactants in the solution and the active sites on the surface of titania mesoporous particles. Considering the photoactivities of the samples, it is revealed that the photocatalytic activity is enhanced, together with an increase in the surface defects in N₂ atmosphere.