Comment on an article by Gonzaga et al. J Am Ceram Soc. 2020;103:6280‐6288

Abstract

I argue that the authors' interpretation of X-ray photoelectron spectroscopy (XPS) Ce3d spectra of their materials is untenable because it largely neglects the electronic structure of cerium ions and spin-orbit interaction of the Ce3d subshell. I conclude that at %Ce 3+ values the authors derived from their Ce3d spectra offer an inaccurate account of the cerium chemistry of their materials. The present Comment deals with the interpretation of XPS Ce3d results that Gonzaga et al put forward in a recent article concerned with CeO 2 and (Ce-Pr)O 2 materials. 1 From the peak-fittings of their Ce3d spectra, the authors derived at%

Reply to “Comment on an article by Gonzaga et al. J Am Ceram Soc. 2020;103:6280‐6288”

“…However, a comparison of this figure with our paper's XPS spectra (see Figure 1 of the present reply) reveals that CeO 2 and CeO 2 :Pr samples in our paper exhibit characteristics of higher at.%Ce 3+ amounts 1,2 . As can be seen clearly in Figure 1 of the present reply, the XPS spectra of CeO 2 and CeO 2 :Pr samples are similar to curve ( d ) of figure 1 of Reference 2, not curve ( b ) as Paparazzo argues. The curve ( d ) is related to at.%Ce 3+ = 24, closer to our calculations 1,2 .…”

“…That author estimated a value of ~10 for the at.%Ce 3+ comparing XPS Ce 3 d spectra in the figure 1 of Reference 2 (which is a reproduction of a figure in the Reference 5) and our results. However, a comparison of this figure with our paper's XPS spectra (see Figure 1 of the present reply) reveals that CeO 2 and CeO 2 :Pr samples in our paper exhibit characteristics of higher at.%Ce 3+ amounts 1,2 . As can be seen clearly in Figure 1 of the present reply, the XPS spectra of CeO 2 and CeO 2 :Pr samples are similar to curve ( d ) of figure 1 of Reference 2, not curve ( b ) as Paparazzo argues.…”

“…Paparazzo argues that our interpretation of XPS Ce 3 d spectra of CeO 2 and CeO 2 :Pr samples is untenable because it largely neglects the electronic structure of cerium ions and spin–orbit interaction of the Ce 3 d subshell 2 . That author estimated a value of ~10 for the at.%Ce 3+ comparing XPS Ce 3 d spectra in the figure 1 of Reference 2 (which is a reproduction of a figure in the Reference 5) and our results.…”

“…Paparazzo argues that our interpretation of XPS Ce 3 d spectra of CeO 2 and CeO 2 :Pr samples is untenable because it largely neglects the electronic structure of cerium ions and spin–orbit interaction of the Ce 3 d subshell 2 . That author estimated a value of ~10 for the at.%Ce 3+ comparing XPS Ce 3 d spectra in the figure 1 of Reference 2 (which is a reproduction of a figure in the Reference 5) and our results. However, a comparison of this figure with our paper's XPS spectra (see Figure 1 of the present reply) reveals that CeO 2 and CeO 2 :Pr samples in our paper exhibit characteristics of higher at.%Ce 3+ amounts 1,2 .…”

“…In the comment on our published article, 1 Paparazzo discuss about the value of Ce 3+ amount determined by the X‐ray photoelectron spectroscopy (XPS) analysis for Pr‐doped and annealed CeO 2 samples 2 . In XPS spectra for Ce‐based materials, 1 Ce 3+ or Ce 4+ components are composed of 10 distinct features in Ce 3 d photoemission spectra 3 .…”