OICC Press Journal of Theoretical and Applied Physics 2251-7235 7 1 2023 11 17 A DFT study of interaction of hydrogen molecules and (5,5) carbon nanotube with bioinspired functionalization 10.1186/2251-7235-7-56 EN Md Shahzad Khan Department of Physics, Jamia Millia Islamia Mohd Shahid Khan Department of Physics, Jamia Millia Islamia Journal Article 2023 11 17 AbstractAll electron density functional theory (DFT) calculations have been carried out for calcium-doped porphyrin-incorporated(5, 5) carbon nanotube (Ca-PICNT) to investigate the formation energies, electronic properties of this system, and its application in hydrogen storage. It is found that the incorporation of porphyrin ring in carbon nanotube led to a decreased value of the highest occupied molecular orbital and lowest unoccupied molecular orbital gap and a strong binding of Ca over nanotube and consequently resulted to a drastic reduction of clustering of Ca atom over Ca-decorated carbon nanotube. The Ca-PICNT can bind a maximum of 4H2 with binding energy value of 0.105 eV per H2 molecule. Charge decomposition analysis indicated that the mode of hydrogen storage is via coulomb-electrostatic force, which is further supported by the natural bond orbital and partial density-of-states studies.