A novel, facile method based on a non-aqueous sol-gel solvothermal process has been developed to synthesise spherical TiO 2 nanoparticles (NPs) in one pot. The reaction between titanium (IV) tert-butoxide (Ti[OC(CH 3 ) 3 ] 4 ) and benzyl alcohol is a simple procedure, that resulted in the formation of highly crystalline titania NPs with a small size of only 6 nm, and with a correspondingly high surface area. The chemical formation mechanism of the metal oxide NPs has been proposed, and the degree of surface hydroxyls (-OH groups) examined. The products of the synthesis were characterised by X-ray powder diffraction (XRPD) including the advanced whole powder pattern modelling (WPPM) method, high-resolution transmission electron microscopy (HR-TEM), thermo-gravimetric analysis (TGA), UV-visible diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR). The photocatalytic activity (PCA) was evaluated both in liquidsolid phase, by monitoring the degradation of an organic dye (methylene blue (MB)) under UV-light irradiation, and in gas-solid phase, by following the degradation of 2-propanol, under UV-and visible-light exposure. The synthesized titania powders showed themselves to be excellent photocatalysts in liquid-solid phase (under UV irradiation), but also to possess a superior PCA in gas-solid phase, under visible-light exposure. The effects on the PCA of the very small crystalline domain size, surface composition and the presence of organic molecules from the synthesis process of the TiO 2 NPs were shown to account for this behaviour.