Ti₂C-MXene/activated carbon nanocomposite for efficient CO₂ capture: Insights into thermodynamics properties

This study investigates the uniqueness and intrinsic properties of a composite material, composed of Ti₂CT_x MXene and activated carbon (AC), for efficient adsorption of CO₂. The evaluation is carried out through a combination of experimental and computational methods at various process conditions. The Ti₂C-MXene/AC nanocomposite materials are synthesized by solid-state impregnation (SSI), and their properties are characterized using techniques such as N₂-sorption, Raman, FTIR, XRD, SEM, and TEM. The characterization results demonstrate that the MXene particles are evenly dispersed and maintain their crystalline structure on the AC surface for maximum adsorption of CO₂. Analyzing the CO₂ isotherm data reveals that incorporating MXene enhances the CO₂ adsorption capacity of AC, with an optimal loading of 2.5 wt% MXene. The adsorption capacity of AC increased from 46.46 cm³/g to 67.83 cm³/g when 2.5 wt% of MXene was introduced. The experimental isotherm data are fitted to Freundlich, Langmuir, Sips, and Tóth, isotherm models. The parameters of these models are employed to determine the thermodynamic characteristics of the adsorption process. The goodness-of-fit of the CO₂ isotherm models is found to be excellent, with R² values consistently exceeding 0.99 in nearly all cases. Thermodynamic analysis indicates that the adsorption processes, favorable, spontaneous, and involve physisorption multiple layers adsorption, while kinetic modeling indicates the dominance of chemisorption in AC-MX-x based adsorbent. Furthermore, a selectivity analysis demonstrates that the adsorbent has a higher affinity for CO₂.