Structure of α-Fe2O3 single crystal surfaces following Ar+ ion bombardment and annealing in O2

Water structure at hematite–water interfaces

“…(0 1 2) surfaces prepared and examined in ultra-high vacuum (UHV) conditions exhibit a stoichiometric bulk-terminated structure (Gautier-Soyer et al, 1996;Henderson et al, 1998;Lad and Henrich, 1988). However, recent work by Tanwar et al (2007b) showed that, when prepared via wet chemical and mechanical polishing, (0 1 2) surfaces exhibited a stoichiometry that was consistent with an incomplete topmost iron layer.…”

Investigation of local structure effect and X-ray absorption characteristics (EXAFS) of Fe (Ti) K-edge on photocatalyst properties of SrTi(1−x)FexO(3−δ)

“…It was obvious that iron in STF x perovskite structure is present as a mixture of Fe 3þ and Fe 4þ (SrTi (1Àx) [Fe 3þ , Fe 4þ ] (x) O (3Àd) ) and with increasing iron dopant the amount of Fe 3þ and Fe 4þ increased significantly. Bocquet et al investigated the electronic structure of the Fe 4þ perovskite oxide SrFeO 3 by XPS, and concluded that the large increase in charge at the Fe site led to a chemical shift to a higher binding energy [49,50,52]. The doublet peaks that appear at 711.8 eV (Fe 2p (b)) and 725.6 eV could be assigned to Fe 4þ .…”

A simple model for the effect of hydration on the distribution of ferrous iron at reduced hematite (012) surfaces

“…This surface can be prepared by oxidation of natural hematite at P O 2 = 10 À6 mbar and 700 K (Gautier-Soyer et al, 1996). After annealing (P O 2 = 10 À10 mbar) at temperature 900 K, the (0 1 2) surface showed a (2 · 1) LEED pattern, indicating surface reconstruction (Gautier-Soyer et al, 1996;Henderson et al, 1998;Lad and Henrich, 1988). The exact atomic structure of reconstructed (2 · 1) surface remains unknown, however, high resolution electron energy loss (HREELS) and Auger spectra have shown that the surface has reduced Fe(II) ions (Henderson et al, 1998).…”