Enhancing the water splitting efficiency of Sn-doped hematite nanoflakes by flame annealing

Abstract

The effect of flame annealing on the water-splitting properties of Sn decorated hematite (α-Fe2O3) nanoflakes has been investigated. It is shown that flame annealing can yield a considerable enhancement in the maximum photocurrent under AM 1.5 (100 mW cm-2) conditions compared to classic furnace annealing treatments. Optimizing the annealing time (10 s at 1000°C) leads to a photocurrent of 1.1 mA cm -2 at 1.23 V (vs. RHE) with a maximum value 1.6 mA cm-2 at 1.6 V (vs. RHE) in 1 M KOH. The improvement in photocurrent can be attributed to the fast direct heating that maintains the nanoscale morphology, leads to optimized Sn decoration, and minimizes detrimental substrate effects. Going up in flames: The effect of flame annealing on the water-splitting properties of Sn decorated hematite nanoflakes was investigated (see figure). Flame annealing can yield a considerable enhancement in the maximum photocurrent under AM 1.5 (100 mW cm-2) conditions compared to classic furnace annealing. This is attributed to the fast direct heating that maintains the nanoscale morphology, leads to optimized Sn decoration, and minimizes detrimental substrate effects (AM=air mass). Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.