Electrochemical synthesis and photoelectrochemical properties of grass-like nanostructured α-Fe_2O_3 photoanodes for use in solar water oxidation

摘要

Grass-like nanostructured α-Fe_2_3 photoelectrodes were prepared for the first time through a simple cathodic electrodeposition method from an oxygenated aqueous solution of Fe~(3+) at room temperature without using surfactant, capping agents or any other additives. The α-Fe_2_3 electrodeposits were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis absorption and photoelectrochemical (PEC) techniques. The SEM and XRD results indicated that the as-deposited α-Fe_2_3 are composed of single crystalline nanoleaves. The formation mechanisms of α-Fe_2_3 have also been proposed based on a series of cyclic voltammetric and XPS studies. This new electrochemical method is expected to be a useful technique for the fabrication of single crystalline and photoactive α-Fe_2O_3 nanostructures directly onto the electrode surface, which is required in most applications, such as energy conversion and storage and sensors.