The analysis of the surface chemistry of carbon materials is of prime importance in numerous applications, but it is still a challenge to identify and quantify the surface functional groups which are present on a given carbon. Temperature programmed desorption with mass spectrometry analysis (TPD-MS) and X-ray photoelectron spectroscopy with an in situ heating device (TPD-XPS) were combined in order to improve the characterization of carbon surface chemistry. TPD-MS analysis allowed the quantitative analysis of the released gases as a function of temperature, while the use of a TPD device inside the XPS setup enabled the determination of the functional groups that remain on the surface at the same temperatures. TPD-MS results were then used to add constraints on the deconvolution of the O1s envelope of the XPS spectra. Furthermore, a better knowledge of the evolution of oxygen functional groups with temperature during a thermal treatment could be obtained. Hence, we show here that the combination of these two methods allows to increase the reliability of the analysis of the surface chemistry of carbon materials.

This work presents the influence of some graphite physico-chemical characteristics such as morphology, structure, textural properties, surface functionality and active surface area (ASA) on the electrochemical performance. The reversible and irreversible capacities, SEI formation at different charging rates, cycling ability have been determined using alkylcarbonate based electrolytes containing LiTFSI as main salt. Three families of graphites have been investigated by SEM, XRD, N2 adsorption, Temperature Programmed Desorption (TPD-MS), and their physico-chemical properties have been correlated to some extent to their electrochemical performances. The irreversible capacity at first cycle increases with the active surface area (ASA) and the specific surface area. The applied current density plays an important role in the SEI formation as shown by the reversible and irreversible capacities and the SEM observations. The passivation layer is mainly formed by polymeric species along with inorganic salts such as Li2CO3 or Li alkylcarbonates (ROLi) as revealed by XPS measurements. Nevertheless, very small quantities of LiTFSI degradation compounds have been detected (LiF, SOx) along with a reversible capacity fade.

Adsorptive removal of dibenzothiophene (DBT) and 4, from model diesel fuel with 20 ppmw total concentration of sulfur was investigated on polymerderived carbons with incorporated heteroatoms of oxygen, sulfur and phosphorus. The materials before and after exposure to model diesel fuel were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The results indicated that the presence of phosphorus, especially in the form of pyrophosphates and P 2 O 5 , increases the capacity and selectivity for removal of dibenzothiophenes. It also affects the adsorption mechanism. Phosphorus suppresses oxidation reactions of DBT and DMDBT. Owing to a possible location of bulky phosphorus groups in pore with sizes between 10-30 Å thiophenic molecules are strongly adsorbed there via dispersive forces. Acidic environment also enhances adsorption via acid-base interactions. Physical adsorption mechanism and stability of surface make these carbons attractive candidates for thermal regeneration.

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