COMPUTATIONAL MODELLING AND SIMULATION OF CARBON DIOXIDE CAPTURE BY CARBON CAPTURING COMPOUNDS

Abstract

Carbon dioxide adsorption studies have been gaining popularity in the world since last two decades. Researchers reported CO2 adsorption on solid surfaces; however theoretical benefits for adsorption studies are still needed to explore. In the current study, ten heterocyclic compounds and transition metal oxide functionalized graphene were selected to understand the adsorption behavior of CO2 at molecular level using theoretical and computational DFT/LDA+GGA+METAGGA approach along with DZ basis set. To explore the mechanism of adsorption, we investigated the thermodynamic, kinetic and electronic parameter before and after complex formation. Thermodynamic parameter (ΔG, ΔH and ΔS) were also determined for the spontaneity of adsorption reaction of CO2 on heterocyclic compound and transition metal oxides functionalized graphene. ΔG values were found to be more negative for PU and PHEN i.e; -118.9 kJ/mol and -143.6 kJ/mol respectively. Highest adsorption constant KD was also found for PU and PHEN i.e; 7.0 ×1020 M-1 at 3 A0 and 1.5 ×1025 M-1 at 6 A0 respectively. Enthalpic and entropic contribution for ΔH and ΔS supported the maximum binding of CO2 with PU and PHEN. However, EHOMO, ELUMO and density of state has verified the maximum electron transfer with the formation of stable complex. TiO2 functionalized graphene depicted favorable ΔEads and KD as compared to ZnO, NiO, AuO and Ag2O functionalized graphene. ΔG value -223.9 kJ/mol considered the favored adsorption for graphene-TiO2 and contributed towards the more spontaneity of the adsorption process. The study revealed excellent viability for the application of CO2 capturing device and gas sensor devices.