Abstract: Water pollution has become one of the critical environmental issues threatening human survival and development. In recent years, photoelectrocatalysis (PEC) technology has attracted extensive attention due to its ability to effectively degrade organic pollutants in wastewater. However, traditional TiO₂ photoanodes suffer from narrow visible light response range and facile recombination of photogenerated charge carriers, which limit their PEC performance. This study successfully constructs a ternary composite photoanode of TiO₂/Fe₂O₃/FeOOH with a stepwise charge transfer pathway by incorporating non-toxic and low-cost Fe₂O₃ and FeOOH into TiO₂. The introduction of Fe₂O₃ significantly broadens the light absorption range, while FeOOH facilitates hole migration toward the interface and accelerates surface oxidation reaction kinetics. Meanwhile, the heterostructure formed between TiO₂ and Fe₂O₃ enables efficient spatial separation of photogenerated electrons and holes, greatly suppressing carrier recombination. Tests in a three-electrode system show that the photocurrent density of this ternary composite electrode reaches 0.42 mA/cm²—seven times higher than that of pure TiO₂ electrodes—while the Tafel slope is only 82 mV/dec, just one-fourth of that for pure TiO₂. Degradation experiments using typical organic pollutants (MB, RhB, and BPA) demonstrate that the composite electrode achieves degradation efficiencies of 95.30%, 92.27%, and 95.67% for MB, RhB, and BPA, respectively, within 2.5 h, indicating high efficiency in pollutant removal and promising potential for PEC applications. Based on radical trapping experiments, the photocatalytic degradation mechanism was further explored, revealing that reactive oxygen species (ROS), primarily superoxide radicals (·\mathrmO_2^- ) and hydroxyl radicals (·OH), play dominant roles throughout the process.