Herein, we report a systematic study on the electronic structure of surface and bulk TiO2 doped with C, N or S. The results were attained with a semi-empirical method consisting of a combination between resonant X-ray emission spectroscopy (RXES) measurements and localized density of states (LDOS) simulations. Experimental TiO2 RXES data was used to fit FEFF code empirical parameters, and subsequently frozen for the theoretical analysis of LDOS of TiO2 doped materials. The results show significant electronic structure differences between bulk and surface doping, as well as in the nearest Ti atom electronic structure if it is located at the surface or sub-surface, with potential consequences to the photo-catalytic process. The methodology can be adapted to study other dopants, morphologies, structures and surface terminations and as well as other inorganic semiconductors. (C) 2018 Elsevier B.V. All rights reserved.