Chemical state analysis using Auger parameters for XPS spectrum curve fitted with standard Auger spectra

Abstract

Chemical state analysis is quite important in X‐ray photoelectron spectroscopy. Auger parameter analysis is one of the useful methods to analyze the chemical state in X‐ray photoelectron spectroscopy, because it is not necessary to take the charging effect into account for the analysis of nonconductive materials, especially for the simple material systems of a single chemical state. For the analysis of complicated complex systems, here, we developed the Auger parameter analysis combined with the curve fitting calculation using standard Auger spectra. Copper oxide complexes consisting of a mixture of CuO and Cu2O oxide states were formed on copper platelets by annealing in atmospheric ambient. For those samples, by combining the curve fitting using standard Cu, CuO, and Cu2O Auger spectra, two oxide states were clearly distinguished in the Auger parameter analysis. Thus, this advanced Auger parameter analysis is believed to be promising for the chemical state analysis of complicated complex systems.

Molecular multifunctionality preservation upon surface deposition for a chiral single-molecule magnet

“… 61 The XPS-derived modified Auger parameter (Table S11 † ), insensitive to charging of non-conducting specimens, has the same value (within standard deviation) for 1 , 1@AuNPs and 1@Au(111) , suggesting a constant oxidation state in the three samples. 62 , 63 However, since in XPS, intense Au4f peaks totally cover the Mn3s signals, and Au4p partially interferes with the weak Mn2p signals (Fig. S12 † ), we performed X-ray absorption spectroscopy (XAS) to compare the oxidation state of Mn in 1 and in 1@AuNPs .…”

XPS as a probe for the bonding nature in metal acetates

“…This parameter has proved to be very useful in characterizing different chemical states of the target atom and exploring the electronic structure of surfaces, with the advantage that it is insensitive to either the energy reference level or uniform charging effects. 24,27,52–54 The main utility of the AP derives from the finding that, to a good approximation, for two different chemical states eqn (2) is fulfilled:Δ α ′ = 2Δ R ea where R ea is the relaxation energy of the core-hole that comes from extra atomic contributions (polarization energy) and can be related to the electronic polarizability of the bonds involving the core ionized atom. 55–57 Hence, Δ α ′ accounts for the difference in the final-state effects of the selected atom occurring in two chemical environments.…”

“…This parameter has proved to be very useful in characterizing different chemical states of the target atom and exploring the electronic structure of surfaces, with the advantage that it is insensitive to either the energy reference level or uniform charging effects. 24,27,[52][53][54] The main utility of the AP derives from the finding that, to a good approximation, for two different chemical states eqn ( 2) is fulfilled:…”

Facile One-Pot Synthesis of CuxO/TiO2 Photocatalysts by Regulating Cu Oxidation State for Efficient Solar H2 Production

“…The modified Auger parameter (α′) calculated for TiCu-1, TiCu-2, TiCu-3 and TiCu-4 is 1848.8, 1849.55 and 1851.8, 1851.8, and 1851.9 eV, respectively (Table S1). 43,44 The KE and α′ values are further evidence that Cu species is/are in +1, +1 and +2, +2 and +2 oxidation states in TiCu-1, TiCu-2, TiCu-3, and TiCu-4, respectively. 43,45 The Cu content on the surface of TiO 2 plays a vital role in the photocatalytic water-splitting activity.…”