3D ordered urchin-like TiO2@Fe2O3 arrays photoanode for efficient photoelectrochemical water splitting

Abstract In this work, we report a three-dimensional ordered urchin-like TiO 2 @Fe 2 O 3 arrays as photoanode for photoelectrochemical (PEC) water splitting application by a combination of colloid spheres template, atomic layer deposition and hydrothermal growth route. Combined with a further TiO 2 surface passivation and decoration of water oxidation catalyst of cobalt phosphate (Co-Pi), the urchin-like TiO 2 @Fe 2 O 3 /TiO 2 /Co-Pi composite photoanode yields significantly improved PEC performance with an impressive photocurrent density of 1.58 mA cm −2 at 1.23 V vs. RHE and 3.6 mA cm −2 at 1.6 V vs. RHE, respectively. The significantly enhanced performance could be attributed to the 3D ordered composite structure design that provides large specific area and fast electron transport paths as well as improves the charge separation efficiency and water oxidation kinetics.