AbstractCharge transport mediators are commonly used in photoelectronic devices to promote selective charge transport and mitigate carrier losses. However, related investigations are mainly carried out by the trial‐and‐error method, and a deeper understanding of its local charge transport behavior is still lacking. Herein, a comprehensive study is performed on a BiVO4/Ti3C2 photoanode to reveal its local charge transport properties by combing microprobe technologies and numerical computations. For the first time, a nano‐Schottky junction is directly shown at the BiVO4/Ti3C2 interface and the band bending is quantified with promoted hole transport and prolonged photocarrier's lifetime. These mechanistic insights leverage a path to further optimize performance through interface engineering and achieve a photocurrent of 5.38 mA cm−2 at 1.23 V versus reversible hydrogen electrode. This work provides deeper insight into the function of charge transport mediators in view of interface contact rather than material nature and demonstrates a strategy to improve photoelectrochemical performance through Fermi‐level engineering.