The rational design of heterostructures as an ideal photoelectrode system for H2 and O2 conversion in photoelectrochemical (PEC) system has been regarded as an essential key to boost PEC performance. In this work, to demonstrate the energetic photoanode cell, deposition of a thin layer of Bi2O3 is utilized to hybridize with the 5 wt% Ba-doped TiO2 nanorod heterostructure under the cascading band diagram, where Ba-doping can enhance the charge transport/separation rate in bulk phase, in terms of increasing the donor density, enhancing the bulk electronic conductivity, and increasing the band bending. Furthermore, with optimizing the thickness (∼15 nm) of Bi2O3, the (NiFe)OOH as a cocatalyst was adapted to improve the interfacial charge transfer rate in the PEC cell, reaching the high photocurrent density (J) of ∼4.1 mA/cm2 at 1.23 V (vs. Reversible Hydrogen Electrode) and stability retention of 100%, even after 15 h at 1 M NaOH under 1 Sun illumination condition. The improvement mainly comes from the extended absorption of visible light from the thin Bi2O3 layer, effective transfer/separation of photogenerated charge carriers, and acceleration of water oxidizing reaction, caused by the narrowed band gap and the favorable charge transfer under the cascading band alignment built by the heterojunction, as well as electrocatalyst, offering the timely consumption of photogenerated holes accumulated at the electrode surface.