Titanium dioxide (TiO2) loaded with gold (Au) as noble metal, acts as an efficient photocatalyst that has been extensively investigated for water splitting processes. In this paper, we report on the microstructure of atomic layer deposited titanium dioxide and the crystallinity modification of the material using energetic electron beam irradiation. A rapid high-energy electron beam induced crystallization of the nanostructures has been observed in-situ inside a High-Resolution Transmission Electron Microscope (HRTEM). The systematic crystallization of the nanomaterial occurring under the electron beam irradiation (300 KV) indicates the transformation of the near amorphous material into a mixture of two nuances of TiO2 polymorphs, namely rutile and anatase. We believe that this transformation will enhance the efficiency of water splitting process, as the mixed phases of rutile and anatase are known to possess better optical properties than the individual polymorphs of TiO2. This finding may be of particular interest in developing appropriate heat treatment methods for these nanostructures dedicated to water splitting to increase their efficiency.