Energy-dispersive X-ray spectroscopy (EDS) experiments were performed with an Octan Pro EDS detector (Ametek, Berwyn, PA, USA) to determine the element composition of TiO2 patterns at 20 kV with spot size 7. High-resolution transmission electron micrographs of the samples were obtained using a Transmission Electron Microscope (TEM, Thermo Fisher Spectra 300C) with TEM and Scanning-TEM (STEM) imaging modes operated at 300 kV.