In all cases, the polarons localize on or near the VO-TiO2(101) surface and are qualitatively similar to those observed on the pristine TiO2(101). However, the presence of vacancies leads to polaron formation at more positive potentials and the presence of more polarons on the VO-TiO2(101) than on the pristine TiO2(101) at same potential, as seen in Figure and 3a. Figure demonstrates that the surface charge of VO-TiO2 (101) decreases linearly with gradually increasing negative electrode potential from 1.5 VSHE to -2.0 VSHE, similar to that of ideal TiO2 (101) surface shown in Figure (orange diamonds). A comparison of the slopes in Figures and shows that electron accumulation is easier on the defected surface than on the pristine TiO2 (101) surface. This implies that oxygen vacancies enhance the electron uptake and formation of electron polarons as a function of the electrode potential. Figures 1b and 3e also demonstrate a more oscillatory relationship between Ef and electrode potential on VO-TiO2 (101) than on the pristine TiO2 (101) surface. We tentatively attribute these larger oscillations to the VO-accelerated electron accumulation and polaron formation. Furthermore, we examined the stability of a complete bi-Ti 3+ state trapped by an oxygen vacancy using CIP-DFT-MD simulations, which show that thermal hopping does not occur, see Figure . Thus, it can be concluded that potential-induced Ti 3+ polarons in pristine TiO2 are more mobile than those trapped by oxygen vacancies. Overall, our computational results clearly demonstrate that the electrode potential significantly impacts polaron formation, charge distribution, and an electronic structure of TiO2 (101) both in the presence and absence of oxygen vacancies.