Titanium-vanadium oxo-alkoxy (VTOA) nanoparticles with vanadium addition (V:Ti) between 0 and 20 mol% were prepared via sol-gel method in a chemical reactor with ultra-rapid micromixing. A control of the nucleation and growth process in the reactor permitted synthesis of size-selective V-TiO2 nanoparticles, which were used for the nanocoatings deposition on glass beads. The activity of the prepared photocatalysts (after calcination at 450 °C) was studied by the degradation of methylene blue in aqueous solutions under UVA illumination. A steady decrease of the reaction rate was observed with an increase of the vanadium content. This effect was explained by the residual presence of non-crystallized oxide, which elimination requires further studies.