XPS and factor analysis study of initial stages of cerium oxide growth on polycrystalline tungsten

Abstract

The initial stages of growth of the nanostructured cerium oxide deposited on the polycrystalline tungsten surface by pulsed laser deposition are studied using XPS technique. The population of Ce (III) and Ce (IV) oxidation states in the deposited CeO2−x layers is determined applying factor analysis method. Tungsten atoms react with oxygen from the cerium oxide nanoparticles already at the room temperature, and a layer of tungsten trioxide is formed at the interface. Gradual heating of the samples up to 900 K leads to the increase of the thickness of WO3 oxide layer and a partial reduction of Ce (IV) to Ce (III). The spectra of O (1s) photoelectrons are composed from a signal originating from metal oxides and a signal of surface superoxide and hydroxyl groups. Factor analysis was performed on the spectra of Ce (3d) photoelectrons to determine the position, shape, and intensity of the spectral components belonging to Ce (III) and Ce (IV) oxidation states. We propose a new simple method to generate components of the spectroscopic meaning. The basic idea of our method consists in the use of the slightly positive values instead of zeros to the needle test vector. Two components are required to reproduce the original data within the experimental errors. Copyright © 2015 John Wiley & Sons, Ltd.

Amino-Functionalized MXene Nanosheets Doped with Ce(III) as Potent Nanocontainers toward Self-Healing Epoxy Nanocomposite Coating for Corrosion Protection of Mild Steel

“…The appearance of two peaks of Ce 3d 5/2 and Ce 3d 3/2 at binding energy ranges of 878–893 eV and 894–912 eV, respectively, indicates the presence of both Ce 3+ and Ce 4+ components doped in Ti 3 C 2 MXene-Ce 3+ . , As stated earlier, the encapsulation of Ti 3 C 2 MXene was performed in an aqueous solution at pH 8. In this medium, owing to the presence of O 2 , H 2 O, OH – , and H 2 O 2 as an oxygen reduction intermediate, a portion of Ce 3+ ions is turned to Ce 4+ ions (eqs and ). , …”

“…In this medium, owing to the presence of O 2 , H 2 O, OH − , and H 2 O 2 as an oxygen reduction intermediate, a portion of Ce 3+ ions is turned to Ce 4+ ions (eqs 15 and 16). 45,46 3.2.2. FT-IR and TGA.…”

Ceria–tungsten–tin oxide catalysts with superior regeneration capacity after sulfur poisoning for NH3-SCR process

“…8b), suggesting that the W 6+ is the main tungsten valence. 50 The Sn 3d XPS spectra of the CeWSnO x -800 catalyst showed spin–orbit peaks at 495.1 and 486.7 eV (Fig. 8c), respectively, which indicated that the Sn species on the surface were in the form of Sn 4+ .…”

Redox behavior of potassium doped and transition metal co-doped Ce0.75Zr0.25O2 for thermochemical H2O/CO2 splitting

“…45 The u 000 , u 00 , u, v 000 , v 00 , v peaks were associated to the Ce 4+ state while the u 0 , u 0 , v 0 and v 0 peaks were attributed to the Ce 3+ state. [46][47][48] As can be appreciated in Table 2, the fresh doped samples show a signicant increase in supercial Ce 3+ with respect to the CeZr sample. This suggests that the atoms of the transition metals can enter into the CeZr lattice and then Ce 4+ can be partially converted to Ce 3+ .…”