Crystalline Fe2O3/Fe2TiO5 heterojunction nanorods with efficient charge separation and hole injection as photoanode for solar water oxidation. (April 2016) - Bassi, Prince Saurabh
Abstract: We have constructed a Fe2 O3 /Fe2 TiO5 heterojunction based photoanode deposited on Fluorine Doped Tin Oxide (FTO) substrate by initially fabricating hematite (Fe2 O3 ) nanorods and subsequently pseudobrookite (Fe2 TiO5 ) nanoporous thin film on top of them. Comparatively lower annealing temperature of 650 °C (usually 750 °C or above) was used to avoid degradation of FTO. The crystalline Fe2 O3 /Fe2 TiO5 heterojunction shows a considerable enhancement in photocurrent density ca. 1.4 mA/cm 2 and high surface charge separation efficiency of 85% at operating voltage of 1.23 V vs RHE as compared to its constituents. The crystalline heterojunction showed overall improvement in performance due to enhanced charge separation owing to the favorable band alignment with Fe2 O3 nanorods and efficient injection of photogenerated holes through surface states into the electrolyte observed through Electrochemical Impedance Spectroscopy. Graphical abstract: Highlights: First report of crystalline Fe2 O3 /Fe2 TiO5 heterojunction for solar water splitting. Higher photocurrent density c.a 1.4 mA/cm 2 at 1.23VRHE as compared to pristine oxides. High surface charge separation efficiency of around 85% at 1.23VRHE . Enhanced performance due to efficient surface states mediated hole transfer process.