We report on high-quality polycrystalline Fe-doped TiO₂ (Fe–TiO₂) porous films synthesized via one-step electrochemical oxidation. We demonstrate that delicate properties such as the impurity concentration and the microstructure that strongly influence the performance of the material for photovoltaic and photocatalysis applications can be controlled by adjusting the electrolyte composition. Compared to Fe-doped TiO₂ films prepared with traditional phosphate- or silicate-based electrolytes, our newly synthesised Fe–TiO₂ films contain solely Fe dopants, which results in excellent photocatalytic and photovoltaic performance under visible light irradiation.