How does anodization time affect morphological and photocatalytic properties of iron oxide nanostructures?

Iron oxide nanostructures are promising materials to be used as photocatalysts in different photoelectrochemical applications. There are different techniques in order to synthesize these nanostructures, but one of the most inexpensive and simple method is electrochemical anodization. This method can lead to different nanostructures by controlling its parameters. Anodization time is one of the most critical parameters since it considerably affects the properties of the obtained nanostructures. In this work, different anodization times (5, 10, 15, 30 and 60 min) were studied. The resulting nanotubes were characterized by field emission scanning electron microscopy, Raman laser confocal microscopy, water splitting measurements, Mott-Schottky analysis and electrochemical impedance spectroscopy, in order to test their viability for being used as photocatalysts in photoelectrochemical applications. Results showed that the best photocurrent density values in water splitting tests (0.263 mA m⁻²) were achieved for the sample anodized for 10 min under hydrodynamic conditions. [ABSTRACT FROM AUTHOR]