XPS spectral analysis for a multiple oxide comprising NiO, TiO2, and NiTiO3

By Kota Sakamoto, Fumio Hayashi, Kazuyoshi Sato, Mitsuhiro Hirano, N. Ohtsu. 2020

191 citations recorded by the source corpus.

Abstract XPS spectra collected from a mixture of NiO, TiO2, and NiTiO3 cannot be analyzed using a standard curve-fitting method; thus, principal component analysis (PCA) was conducted to accurately determine the ratio of various oxides in the mixture. Model samples comprising NiO, TiO2, and NiTiO3 exhibited a complex-shaped Ni 2p spectrum with a satellite peak, from which the atomic ratio of NiO and NiTiO3 could be accurately quantified using the PCA. In contrast, the Ti 2p spectrum exhibited a symmetric shape despite comprising both NiTiO3 and TiO2 states; thus, the PCA results predicted the ratio inaccurately. However, the PCA results showed linear correlation with the theoretical values over an entire range. Thus, accurate ratios were obtained using a calibration curve. The PCA procedure for multiple oxides was applied to angle-resolved XPS spectra for thermally oxidized nickel titanium alloy. The results revealed the in-depth distribution of NiO, TiO2, and NiTiO3 on the surface of the alloy.

Subfields: Materials Chemistry, Polymers and Plastics, Surfaces, Coatings and Films

View Paper: https://www.semanticscholar.org/paper/c5914eb701b59bbf1381a5200237772b0e172265