DFT based investigations on inherent CO2 adsorption and direct dissociation capability of Ti2C and Nb2C mxenes

Transition metal carbide MXenes, specifically Ti2C 2 C and Nb2C, 2 C, have been investigated for their ability to efficiently adsorb and dissociate CO2 2 using First Principles Calculations based on Density Functional Theory (FPSDFT). Pure Ti2C 2 C and Nb2C 2 C sheets were studied with the adsorption of 1 to 4 CO2 2 molecules, , and the results were analyzed for each case. For 4 CO2 2 molecules adsorbed on Ti2C 2 C and Nb2C 2 C sheets, the weight percentage (wt%) ratio was found to be 21.39% and 14.33%, respectively. The Density of States (DOS) analysis revealed that, upon CO2 2 adsorption, the CO2 2 molecule dissociates into CO and O atoms on the MXene surface. . The CO molecule showed no significant hybridization with the host sheet atoms, whereas the O atom exhibited strong hybridization with the MXene surface. Transition State (TS) profiles illustrated the dissociation steps on both Ti2C 2 C and Nb2C 2 C surfaces. Phonon calculations confirmed the dynamic stability of both pure and CO2 2 adsorbed MXenes. Molecular Dynamics (MD) simulations conducted at 900 K indicated uniform temperature and Mean Square displacement (MSD) profiles, suggesting the stability of both pure and CO2 2 adsorbed MXenes at elevated temperatures, as well as uniform CO2 2 adsorption behavior. The adsorption energies for Ti2C 2 C and Nb2C 2 C sheets were calculated to be in the range of-1.89 to-2.77 eV, suggesting that the adsorption process is favorable, , spontaneous, and predominantly involves chemisorption. . These findings indicate that Ti2C 2 C and Nb2C 2 C MXenes, in their intrinsic forms, are promising candidates for CO2 2 adsorption and dissociation technologies.