XPS study of the supported CrO₃/SiO₂ system: Elimination of the oxide‐support contribution from the Cr 2p band

Abstract

The main analytical band of chromium, the Cr 2p band, is -30 eV away from the oxygen 0 1s band and so it superposes with the energy loss band (ELB), which is composed of energy loss peaks from inelastically scattered 1s electrons of oxygen (Fig. 1). During studies of chromium-containing catalysts it has been observed that, in the case of samples with low chromium content, Cr 2p binding energies (BE) are lower but full widths at half maximum (FWHM) are much larger than those expected for the Cr6+ oxide forms. This indicates a significant contribution from the ELB structure and the necessity to remove it.To illustrate the meaning of the problem and its solution, the usual XPS analysis can be compared with that after removal of the ELB for a sample of fused silica grafted to chromium oxide using Cr02C12 .l The chromium content was in the monolayer range.The elimination of the ELB was carried out as follows. In the 0 1s spectrum of a pure silica carrier recorded in an 85 eV wide scan (Fig. l), after Shirley's background subtraction, the ELB region was cut off and the band was fitted using a set of Gaussian-20% 2).

Elucidation of the Active Phase and Deactivation Mechanisms of Chromium Nitride in the Electrochemical Nitrogen Reduction Reaction

“…The Cr 2p XPS spectrum of fresh CN-P on the GDL confirms that Cr 2 N is the dominant surface species (574.9 ± 0.2 eV), accounting for 35% of surface Cr. Moreover, multiple other Cr-based species, including CrN, CrO x (OH) y /CrO x N y , and CrO 3 species, are present based on deconvoluted Cr 2p 3/2 bands at 576.0 ± 0.2 eV, 577.0 ± 0.2 eV, and 580.0 ± 0.2 eV, respectively (Figures b, S9, and Table S3). The N 1s region of the same sample shows two sharp peaks at 396.6 ± 0.1 eV corresponding to CrN and 397.8 ± 0.1 eV corresponding to Cr 2 N and CrO x N y (Figure a). ,, A broad and weak peak at 398.5 ± 0.1 eV is attributed to a N 1s satellite feature. − In addition, a broad and weak feature at ∼400 eV is also present, which has been assigned to N from adsorbed ammonia or ammonium species on the surface .…”

Mobility of geogenic chromium in Asopos river basin

“…3B shows the Cr2p peaks which is analyzed into two doublets with a spinorbit splitting 9.1 eV. The binding energy of Cr2p3/2 of the two components is at 574.0 eV assigned to Cr 0 and at 578.1 eV assigned to Cr(VI) (Mikolaichuk et al, 1993).…”