Our results highlight that polaron formation in pristine TiO2 is achieved by changing the electrode potential. However, TiO2 often contains oxygen vacancies and other point defects, which may have decisive role on its (photo)electrocatalytic performance. While TiO2 can host various defects, the Obr is generally regarded as the energetically most favorable surface oxygen defect on anatase TiO2 (101). Therefore, we considered the impact of Obr vacancy (VO) on the polaron generation.