ABSTRACT The photoelectrochemical (PEC) activity of hematite for water oxidation is hindered by sluggish charge‐carrier transport and high electron‐hole recombination rates. To address these issues, this study fabricated a Ti‐doped Fe 2 O 3 /WO 3 heterojunction photoanode on a three‐dimensional (3D) Ti felt substrate via a hydrothermal process yielding Ti‐doped Fe 2 O 3 followed by WO 3 growth. Characterization by XRD, Raman spectroscopy, and FESEM confirmed the composite, consisting of spherical Ti─Fe 2 O 3 particles and irregular WO 3 nanorods. The Ti─Fe 2 O 3 /WO 3 heterojunction demonstrated improved PEC activity, achieving a current density of 0.106 mA cm −2 at 1.23 V versus RHE, representing approximately a threefold enhancement over the pristine Ti─Fe 2 O 3 photoanode. This enhanced performance is attributed to effective band engineering induced by WO 3 modification. Photoelectron yield and x‐ray photoelectron spectroscopy indicated that the formation of the heterojunction shifted the valence and conduction band positions of Fe 2 O 3 by 0.5 and 0.6 V, respectively, to more negative potentials. Electrochemical impedance spectroscopy and Mott–Schottky analyses confirmed that the reduced charge‐transfer resistance and a high donor density ( N D = 5.6 × 10 21 cm −3 ), consistent with the enhanced PEC performance. This fabrication strategy leverages a well‐engineered heterojunction on a 3D substrate to enable efficient solar‐driven water oxidation.
Bodro et al. (Wed,) studied this question.