The surface modification of semiconductor photoelectrodes with passivation overlayers has attracted great attention as an effective strategy to improve the charge separation and charge transfer processes across the semiconductor-electrolyte interface. In this work, a thin Fe₂TiO₅ layer was decorated on nanostructured hematite nanoflake and nanocoral photoanodes (by thermal oxidation of iron foils) by a facile water-based solution method. Photoelectrochemical measurements show that the Fe₂O₃/Fe₂TiO₅ heterostructure exhibits an obvious enhancement in photoelectrochemical water oxidation performance compared to the pristine hematite. For example, at 1.23 V versus the reversible hydrogen electrode (V_RHE) in 1 m KOH under AM 1.5 G (100 mW cm⁻²) illumination, a 4–8× increase in the water oxidation photocurrent is achieved for Fe₂O₃/Fe₂TiO₅, and a considerable cathodic shift of the onset potential up to 0.53–0.62 V_RHE is obtained. Moreover, the performance of the Fe₂O₃/Fe₂TiO₅ heterostructure can be further improved by decoration with a SnO_x layer. The enhancement in photocurrent can be attributed to the synergistic effect of Fe₂TiO₅/SnO_x overlayers passivating surface states, and thus reducing surface electron–hole recombination.