Form Of Fe2O3 Research Articles

Studies of α-Fe2O3 electrode surface of wet cells for the photodecomposition of water

Abstract In this paper the experimental results on stoichiometric α-Fe 2 O 3 , surface sputtered by Ar + ions are reported. It is demonstrated that on the sputtered surface there exist Fe 2+ ions in the form of FeO. Owing to the catalytic action of the 3d electrons of the surface Fe 2+ , water is adsorbed dissociatively on the surface. We also identify by UPS, XPS, and SIMS techniques that OH − exists on the FeO-like surface after the exposure to H 2 O vapor. We demonstrate that the Fe 2+ ions on the surface are the active centers for the decomposition of water. Therefore, to increase the efficiency of the decomposition of water, it is important to have active Fe 2+ centers on the α-Fe 2 O 3 surface in addition to the effects of band structure and conductivity of the material.

Studies of α-Fe 2O 3 electrode surface of wet cells for the photodecomposition of water

In this paper the experimental results on stoichiometric α-Fe 2O 3, surface sputtered by Ar + ions are reported. It is demonstrated that on the sputtered surface there exist Fe 2+ ions in the form of FeO. Owing to the catalytic action of the 3d electrons of the surface Fe 2+, water is adsorbed dissociatively on the surface. We also identify by UPS, XPS, and SIMS techniques that OH − exists on the FeO-like surface after the exposure to H 2O vapor. We demonstrate that the Fe 2+ ions on the surface are the active centers for the decomposition of water. Therefore, to increase the efficiency of the decomposition of water, it is important to have active Fe 2+ centers on the α-Fe 2O 3 surface in addition to the effects of band structure and conductivity of the material.

An Electron Diffraction Study of the Effects of Heat Treatment on -Fe2O3(Haematite) Single Crystals

Electron diffraction patterns have been taken from a large variety of natural single crystals of α-Fe2O3 (haematite) which had previously been heated to 500°C. Some of these showed additional patterns similar to those observed by Finch and Sinha in 1957. Measurements of the basic plane spacings associated with the extra patterns showed that these differed considerably from the corresponding basic plane spacings of α-Fe2O3. This result is in contradiction to the findings of Finch and Sinha who claimed that the basic plane spacings associated with the extra patterns approximated closely to those of α-Fe2O3. There is therefore no justification for assuming that a new form of Fe2O3 (β-Fe2O3) exists.

The fine structure of submicron iron particles

High resolution electron micrographs are shown of samples of colloidal alpha iron. According to the conditions of manufacture the samples occur as (1) large, well-formed dendrites, (2) shorter, more fragile dendrites, (3) serrated rods, (4) needles and (5) cubic particulates. The central stem is a line-up of single cubic crystals. Representative dimensions are given for the various measurable units. A fine laminar structure in the cubic particulates, and some of the side branches and main stems is noted. The same laminar structure is observed in some of the background platelet material from the mother liquor. Stereoscopic studies show that the dendrites are three dimensional with their branches and main stem not in the same plane. X-ray diffraction detects alpha iron plus some form of Fe2O3 in most samples.