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Activated carbon fibers (ACFs) as one of the most important porous carbon materials are widely used in many applications that involve rapid adsorption and low-pressure loss, including air purification, water treatment, and electrochemical applications. For designing such fibers for the adsorption bed in gas and aqueous phases, in-depth comprehension of the surface components is crucial. However, achieving reliable values remains a major challenge due to the high adsorption affinity of ACFs. To overcome this problem, we propose a novel approach to determine London dispersive components ( γ S L ) of the surface free energy of ACFs by inverse gas chromatography (IGC) technique at an infinite dilution. Our data reveal the γ S L values at 298 K for bare carbon fibers (CFs) and the ACFs to be 97 and 260–285 mJ·m−2, respectively, which lie in the regime of secondary bonding of physical adsorption. Our analysis indicates that these are impacted by micropores and defects on the carbon surfaces. Comparing the γ S L obtained by the traditional Gray's method, our method is concluded as the most accurate and reliable value for the hydrophobic dispersive surface component of porous carbonaceous materials. As such, it could serve as a valuable tool in designing interface engineering in adsorption-related applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Graphene is of great interest for many far-reaching applications that involve interparticle interactions in adsorbents, coatings, and composites. A deep understanding of the surface components has been crucial but achieving the most accurate and reliable values of these, unaffected by experimental conditions or the analytical techniques used, remains a major challenge. To this end, we have proposed in this paper a novel approach for the first time, to the best of our knowledge, to determine London dispersive and specific (polar) components including the Lewis acid-base character of the surface free energy of graphene materials (graphene oxide (GO), reduced graphene oxide (rGO), and graphite) using inverse gas chromatography (IGC) technique at an infinite dilution. We have estimated the London dispersive surface energy values of graphite, GO, and rGO as van der Waals interaction to be 156–179, 89–106, and 110–119 mJ m−2, respectively, in the temperature range of 320–360 K. These are attributable to the surface properties impacted by the oxygen moieties, defects, and micropores on the carbon frameworks. Further, the acceptor (K A) and donor (K D) parameters of GO were found to be 0.71 and 0.96, respectively, while those of rGO were 0.54 and 1.05. Notably, the GO is more of the Lewis acid character that could be amphoteric, while the Lewis base characteristics of both GO and rGO are not significantly changed. These results provide foundational knowledge to understand the physicochemical properties of graphene surfaces, which should be helpful to designing interface engineering in various applications. [ABSTRACT FROM AUTHOR]