The effect of fluorine doping on the photocatalytic properties of hematite for water splitting

Fluorine-doped hematite samples with different concentrations were successfully synthesized through a hydrothermal method. The 3% F-doped hematite is found to be the optimal catalyst in this study which has a [110]-oriented structure and a remarkable photocurrent density of 1.24 mA cm(-2) at 1.23 V vs. RHE under one sun irradiation, which is about ten times higher than that of bare hematite (0.12 mA cm(-2)). F doping also reduces the recombination of free electron-hole pairs. The shift of the Fermi level position caused by F doping leads to the decrease of charge-transfer resistance in the bulk (R-1) and interface (R-2) and the increase of charge carrier concentration (N-d). In addition, F doping contributes to the shadow defect. All the results indicate that 3% F is the best doping concentration.