## 1 Introduction  
The surface and microstructural properties of carbons are very relevant to their use in consolidated and emerging applications as fuels, adsorbents/catalysts for chemical and environmental applications, or electrodes/supercapacitors for energy storage [1; 2; 3; 4; 5; 6]. The characterization of the surface chemistry of carbons is of primary importance for the proper design and tailoring of smart carbon materials. Among the most widely used and effective surface characterization methods are X-ray photoelectron spectroscopy (XPS) [7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18], Fourier-transformed infrared spectroscopy (FTIR) [19; 20; 21], temperature-programmed desorption (TPD) [7; 22; 23; 24; 25; 26; 27; 28; 29; 30], and attenuated total reflectance (ATR) [31; 32]. Due to its sensitivity to the chemical composition and environment of atomic species, XPS has been extensively utilized to determine the carbon structure features on the surface of graphite and graphene oxides, providing valuable insights into the mechanical and electronic properties of these materials [9; 12; 13; 14]. [PERSON] et al. [7; 15] used XPS to scrutinize the nature of carbon-oxygen functionalities as intermediates in the heterogeneous oxidation of different types of coals and synthetic carbons. Surface chemistry has been correlated with the exothermicity or endothermicity of reactions occurring during oxidation and desorption investigated by thermoanalytical methods (DTG, DSC, TPD). Studies on heterogeneous carbon-oxygen chemistry are relevant to the combustion and gasification of carbon from either fossil or biogenic renewable sources to improve efficiency and reduce CO\({}_{2}\) emissions to the atmosphere [33]. The nature of carbon-oxygen complexes and the mechanisms underlying the desorption of CO and CO\({}_{2}\) under steady and dynamic conditions have been further investigated in [34; 35]. Results from oxidation/desorption experiments are fully consistent with the characterization of the nature and extent of surface oxides formed on the carbon substrate, assessed via XPS spectral intensities. In particular, the CO/CO\({}_{2}\) ratio in the off gas turns out to be a meaningful fingerprint of the relative abundance of \"edge\" oxides (ether, carbonyl, lactone) versus epoxy moieties assessed via XPS. However, the XPS data interpretation of heterogeneous samples, characterized by non-uniform electrical conductivity, may not be straightforward. It is widely recognized that the positive charge generated on the sample surface during the photoemission process is neutralized by an electric current to the grounded sample when the sample's conductivity is prominent, as well as by metals and semiconductors. In contrast, for insulating materials, neutralization is only partial, leading to the accumulation of a significant net positive charge on the surface [36; 37; 38; 39]. As a result, the sample surface develops a positive potential, typically ranging from a few volts to several tens of volts, which results in a lower measured kinetic energy of the photoelectrons and, as a consequence, a higher apparent binding energy. If the charging is very strong, the shift in binding energy may be large to the point of hiding the photoelectron peak in the secondary electron tail. In intermediate cases, the BE shifts lead to difficulties in interpreting the chemical states of the elements or even in the identification of the observed chemical species. The situation is further complicated for composite samples, in which case effects like differential charging [40], where regions with different conductivities are present, can entail different retarding potentials and lead to peak broadening and even distortions [41].