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

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.