Magnetite, goethite, and lepidocrocite thin films have been electrochemically grown on titanium substrates by the anodic oxidation of ferrous ions in a <mml:math display="inline"><mml:mrow><mml:mn>0.01</mml:mn><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">M</mml:mi></mml:mrow></mml:math>0.01M <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Fe</mml:mi><mml:mi mathvariant="normal">S</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi mathvariant="normal">N</mml:mi><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:mo form="postfix">∙</mml:mo><mml:mn>6</mml:mn><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mo>+</mml:mo><mml:mn>0.04</mml:mn><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">M</mml:mi></mml:mrow></mml:math>FeSO4(NH4)2SO4∙6H2O+0.04M <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">C</mml:mi><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mi mathvariant="normal">C</mml:mi><mml:mi mathvariant="normal">O</mml:mi><mml:mi mathvariant="normal">O</mml:mi><mml:mi mathvariant="normal">K</mml:mi></mml:mrow></mml:math>CH3COOK , pH 6.0, aqueous solution. It is demonstrated that the deposition potential can be used as a tool to tune the obtainment of the different pure phases of the iron oxide-oxyhydroxides thin films. Results of an exhaustive structural characterization, a morphological study, and X-ray photoelectron spectroscopy characterization are presented.

Electrochemical deposition of hematite thin films was investigated on covered glass substrates. A new electrochemical method to obtain hematite thin films through a potential cycling procedure in an aqueous solution of at room temperature is presented. The electrodeposited iron oxide thin films submitted to an annealing treatment showed a good quality and crystallinity. X-ray diffraction analysis confirmed the presence of the rhombohedrally centered hexagonal structure: , hematite, as the sole crystalline phase. A bandgap energy of ca. was measured for these films.

The electrochemical formation of hematite precursor thin films (oxyhydroxide iron compounds), onto gold substrates in an aqueous solution of was investigated in situ using an electrochemical quartz crystal microbalance (EQCM) and voltammetric techniques. Nanostructured obtained after annealing of oxyhydroxide iron compounds thin films have been prepared onto covered glass substrates through a potential cycling procedure in this electrolytic bath. Photoelectrochemical measurements, carried out in electrolyte at pH 13, show an n-type behavior, a flatband potential of vs saturated mercury/mercury sulfate reference electrode, and an apparent donor density of at .

Photoelectrochemical response of electrodeposited hematite (α-Fe₂O₃) thin films, whose surface has been modified by a catalytic cobalt layer, has been studied. Structural and morphological characteristics of the resulting nanostructured hematite films have been studied by X-ray diffraction and scanning electron microscopy techniques. Surface characterization of the Co-modified hematite films has been carried out by X-ray photoelectron spectroscopy in order to study the chemical nature of Co onto these films. The hematite films exhibited an n-type behavior, and a donor carrier concentration, N_D = 3 × 10₁₇ and 10₁₈ cm₋₃ for the un-modified and Co-modified ones, respectively. The photoelectrochemical performance of the un-modified and Co-modified electrochemically grown hematite thin films has been explored using a liquid-junction in a photoelectrochemical system in a 0.1 M NaOH electrolytic solution, under monochromatic illumination of wavelengths over the range 350–600 nm. Significant performance gaining can be seen upon Co-modification throughout the illumination wavelengths. Cobalt modification enhances the IPCE by a factor of 1.1–2.0 (370–450 nm range), and by a factor of 2.0 (at 350 nm). With an IPCE of 46% at 370 nm at 1.43 V vs. RHE, this electrode is much more efficient in water photo-oxidation than the best published Fe₂O₃ single-crystal specimen.