I've observed a consistent phenomenon in TiO2 XPS spectra, which is the presence of a minor peak at 75 eV. This peak is noticeable in both commercially available TiO2 powder and in all the TiO2 samples I've synthesized. After a thorough examination of elements known to exhibit peaks around this binding energy (75 eV), none of them seem to have main peaks in the survey spectra. Consequently, I'm left wondering about the origin of this particular peak.