It should be noted that this observation is in stark contrast to the data for Mo-doped BiVO4 (with similar doping concentration) reported by Ye et al. who observed a slight negative shift of the OCP after Mo-doping. However, our observation of a positive shift of the OCP after the Mo-doping is completely in line with the observed decrease of photocurrent at low bias potentials induced by the Mo-doping (Fig. ), and suggests that the Mo-doping does not have only beneficial effects, such as the enhancement of photocurrents at relatively high bias potentials, but also induces effects that are detrimental to the PEC performance.