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 (-Fe2O3) nanoflakes has been investigated. It is shown that flame annealing can yield a considerable enhancement in the maximum photocurrent under AM 1.5 (100mWcm(-2)) conditions compared to classic furnace annealing treatments. Optimizing the annealing time (10s at 1000 degrees C) leads to a photocurrent of 1.1mAcm(-2) at 1.23V (vs. RHE) with a maximum value 1.6mAcm(-2) at 1.6V (vs. RHE) in 1M 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.