Structure and catalysis of layered rock-salt type oxides for methane oxidation

Abstract

A comparison of X-ray photoemission spectra of LiFeO 2, LiCoO 2, and Li x Ni 2− x O 2 for the range of 0 < x ≤ 1 have been measured. A main O 1s XPS peak of LiNiO 2 and LiCoO 2 with a hexagonal type was observed at 531.9 eV, while that of LiInO 2, LiFeO 2 with a tetragonal type and Li x Ni 2− x O 2 ( x < 0.6) with a cubic type were about 531.4 eV. It was inferred from these results that the layered superstructure of LiNiO 2 and LiCoC 2 largely affected the formation of the active oxygen species for the high selective coupling reaction of methane.