Adsorption, sensing and catalytic properties of the pristine C24N24 nanocage to small gas molecules: A DFT-D3 investigation

Adsorption of small gases (H2, N2, O2, CO, NO, CO2, N2O, NO2, H2S, H2O, SO2, NH3, CH4, C2H4, and C2H2) on the C24N24 (noted by CNNC) was studied using the B3LYP-D3/6-31G(d,p) method. Adsorption energies and ther-modynamics of all the studied gases adsorbed onto the CNNC and NBO charge analysis of their adsorption structures were obtained. Adsorption ability of the CNNC on gases was in order: H2O (Delta Eads =-25.06 kcal/mol) > SO2 (Delta Eads =-11.84 kcal/mol) > NH3 > C2H2 > H2S > N2O > CO2 > NO2 > O2 > NO > C2H4 > CH4 > SO2 > CO > H2 > N2. The high adsorption strength The CNNC was suggested to be a storage material for all studied gases and a potential to be a sensing material for NO. On the CNNC surface, co-adsorption of H2O and SO2 conversion to H2CO3 assumed as Langmuir-Hinshelwood mechanism and co-adsorption of H2O and CO2 co -adsorbed on the CNNC surface was assumed as Langmuir-Rideal mechanism were found. The H2O phys-isorption over C-N bond of the CNNC to form dissociative chemisorption on C-N bond via transition-state barrier was found.

Automated summary

The adsorption of small gases on CNNC was studied and the adsorption energies and thermodynamics were obtained. The CNNC showed high adsorption strength and can be used as a storage material for the studied gases and a potential sensing material for NO. Different adsorption mechanisms were observed on the surface of CNNC.