Comments on the XPS Analysis of Carbon Materials

Abstract

The surface chemistry of carbon materials is predominantly explored using x-ray photoelectron spectroscopy (XPS). However, many published papers have critical failures in the published analysis, stemming from an ill-informed approach to analyzing the spectroscopic data. Herein, a discussion on lineshapes and changes in the spectral envelope of predominantly graphitic materials are explored, together with the use of the D-parameter, to ascertain graphitic content, using this information to highlight a simple and logical approach to strengthen confidence in the functionalization derived from the carbon core-level spectra.

Tuning the Coordination Structure of CuNC Single Atom Catalysts for Simultaneous Electrochemical Reduction of CO2 and NO3– to Urea

“…The high‐resolution C 1s (Figure S10, Supporting Information) and O 1s (Figure S11, Supporting Information) spectra confirm the absence of Cu carbides or oxides in the catalysts, with peaks in the C 1s spectra representing graphite‐like CC (284.5 eV), CN (285.9 eV), and CO and OCO species (287.8 and 288.6 eV, respectively). [ 36,37 ] The Cu 2p spectra (Figure S12, Supporting Information) show that only one type of Cu species is present, the oxidation state of which inconsistent with tabulated Cu 0 and Cu 2+ compounds. [ 38 ] A Cu surface concentration of ≈0.1 at% (0.5 wt%) was measured by XPS (Table S1, Supporting Information).…”

Redox Replacement of Silver on MOF‐Derived Cu/C Nanoparticles on Gas Diffusion Electrodes for Electrocatalytic CO2 Reduction

“… [25] The broad C 1s spectrum was deconvoluted into C−C (284.8 eV), C=C (284.4 eV), C−O (286.2 eV), C=O (287.6 eV), and O=C=O (288.9 eV; Figure S7). [26] The XPS spectra of the Ag@Cu/C‐3 to Ag@Cu/C‐24 GDEs were also deconvoluted into elemental Cu 0 (core level Cu 2p 3/2 , binding energy 932.6±0.2 eV; Figures 3 c, d and S8). The Ag@Cu/C‐34 GDE revealed an additional Cu I component, also supported by Cu LMM Auger spectra.…”

A Redox-Mediator-Integrated Flexible Micro-Supercapacitor with Improved Energy Storage Capability and Suppressed Self-Discharge Rate

“…The measured electrical resistance of the We also carried out X-ray photoelectron spectroscopy (XPS) measurements to determine the surface properties of the GCEs (Figure 2c). The GCEs exhibited a common graphite characteristic with a strong C-C peak clearly observed at 284.6 eV, which indicates a high degree of formation of layered graphite structures [37][38][39]. In addition, as shown in Figure 2d, the as-prepared GCEs showed a highly porous structure based on a three-dimensional network, owing to the rapid formation of gaseous species produced during laser irradiation.…”