Three and one-dimensional hierarchical α-Fe2O3 nanostructures for photoelectrochemical water oxidation

Herein, we report the synthesis of three-dimensional (3D) and one-dimensional (1D) hierarchical hematite (α-Fe2O3) nanostructures on fluorine-doped tin oxide (FTO) glass substrate by hydrothermal and hybrid microwave annealing (HMA) process for photoelectrochemical (PEC) water oxidation. The properties of prepared α-Fe2O3 nanostructures were characterized by different characterization techniques. Moreover, the PEC water oxidation performance of the α-Fe2O3 nanostructures was studied under simulated solar irradiation. The 3D α-Fe2O3 nanostructures shown an enhanced photocurrent density of 0.48 mAcm−2 at 1.23 V vs. RHE when compared with 1D α-Fe2O3 nanostructure (0.07 mAcm−2 at 1.23 V vs. RHE) under 100 m Wcm−2 solar irradiation. This result demonstrates that the 3D α-Fe2O3 nanostructures have higher PEC water oxidation ability than 1D α-Fe2O3 nanostructure. The enhancement in the PEC water oxidation process was due to the higher electrical conductivity with suppressed charge recombination rates.