Sn-doped hematite modified by CaMn2O4 nanowire with high donor density and enhanced conductivity for photocatalytic water oxidation.

Herein, we report a novel nanocomposite consisting of n-type Sn-doped hematite and p-type CaMn2O4 nanowire (CaMn2O4/α-Fe2O3). The nanocomposite was characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), ultraviolet-visible absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), which showed that nanospindle-like Sn-doped hematite and CaMn2O4 nanowire contact intimately in the nanocomposite, resulting in efficient charge transfer and separation. Photoelectrochemical results reveal that the nanocomposite possesses higher donor density, enhanced conductivity and lower overpotential for dioxygen evolution. In addition, the nanocomposite demonstrates high photocatalytic activity for water oxidation to produce oxygen in a photoelectrochemical cell. The amount of O2 evolved from the optimized photoanode of the photoelectrochemical cell was 1.98 μmol in 2 h of simulated sunlight irradiation. This work demonstrates a facile synthesis of a novel nanocomposite as anode material for photocatalytic water oxidation to produce O2.