Characterization of the Surface of α-FeOOH Powder by XPS

Abstract

We report x-ray photoemission spectra of the surface of iron (III) oxyhydroxide (α-FeOOH) particles. Research grade purity (99.0%) α-FeOOH sample was commercially obtained from Alfa/AESAR. The XPS spectra were measured with the Physical Electronics Model 5400 X-ray Photoelectron Spectrometer using unmonochromated Mg Kα x-rays at two pass energy settings corresponding to analyzer energy resolutions of 1.34 and 0.54 eV. We present the survey spectrum (binding energy range of 0–1100 eV) measured at an analyzer energy resolution of 1.34 eV. Multiplexes of the C 1s, O 1s and 2s, Fe 2p and 3p photoemission lines, valence band region as well as the Fe L3VV Auger line were measured at an analyzer energy resolution of 0.54 eV. The XPS spectra indicate that the surface of α-FeOOH powdered material consists mainly of its bulk chemistry with small quantities of oxidized carbon and hydrocarbon as contaminants.

Analytical utility of valence band X-ray photoelectron spectroscopy of iron and its oxides, with spectral interpretation by cluster and band structure calculations

“…Table 2 gives the details of the binding energies of the principal core peaks and the O2 s region of the valence band. The results agree with previously published studies of core and valence band features for metallic iron [24,25], FeO [26], Fe 3 O 4 [12,27,28,29], α-Fe 2 O 3 [28,30], γ-Fe 2 O 3 [28,31], α-FeOOH [30,32], and γ-FeOOH [28,31].…”

Systematic Investigation of the Electronic Structure of Hematite Thin Films

“…When comparing valence band spectra of nominally hematite phases from the last decades quite drastic differences can be noticed . The features of the valence bands are different from one study to the other.…”

Nanosheets of iron-based compounds : synthesis and their lithium storage properties

“…The specific surface areas were calculated using Brunauer-Emmet-Teller (BET) method. The 2p1/2 and 2p3/2 photoelectrons at 711 and 724 eV of the Fe 2p XPS data ( Figure 5-2b) correspond to the reported values for Fe 3+ in Fe2O3 or FeOOH, [182,183] which confirms complete oxidation from Fe 2+ to Fe 3+ . The XPS spectrum of oxygen ( Figure 5-2c) can be convoluted to three distinct peaks, implying that oxygen presents in three different states.…”

“…The two convoluted peaks at 530.10 eV and 531.50 eV can be assigned to O 2and OHin FeOOH, respectively. [182,183] To characterize chemical bonding in this amorphous compound, FTIR was conducted in the wavenumber range of 400-4000 cm -1 . Figure 5-3a displays the FTIR spectrum of the amorphous sample and its crystalline counterpart, which is obtained by annealing the amorphous sample at 800 o C. The annealed sample is identified to be α-Fe2O3 (JCPDF #00-039-1346) by XRD pattern in Figure 5-3b.…”