Theoretical investigation of metalloporphyrin-induced C₈₂ fullerene as a hydrogen storage material via DFT

چکیده مقاله

The density functional theory (DFT) calculations were utilized to investigate the optimized structure and electronic properties of the Fe and Mg—transition metal-porphyrin induced C₈₂ fullerene (TM-PIC₈₂F). After inducing porphyrin into the C₈₂ fullerene by removing two carbon atoms and replacing the closest neighbor carbon atoms with four nitrogen (PIC₈₂F), the adsorption of Fe and Mg atoms into three isomers of PIC₈₂F was investigated. The Fe and Mg elements were adsorbed into PIC₈₂F through chemisorption with adsorption energy equal −36.42, −20.08, and −18.28 kcal/mol for A, B, and C isomers of Fe-PIC₈₂F; and −14.49, −14.94, and −14.25 kcal/mol for A, B, and C isomers of Mg-PIC₈₂F, respectively. The strong binding energy of adsorption H₂ molecule over the Fe-PIC₈₂F as compared to its Mg-PIC₈₂F was indicated that Mg-PIC₈₂F could be proper candidate for hydrogen storage. The results of investigation the electronic properties also were exhibited that the changes of band gap (E_g) were appropriate. The binding energy, NBO and DOS analysis were confirmed that the TM-PIC₈₂F structures are highly stabilized structures in three designed isomers. A large binding energy was realized for Fe-PIC₈₂F in each isomer which was confirmed a chemisorption process. However, the favorable binding energy was obtained for Mg-PIC₈₂F in three isomers which was indicated a strong physisorption process. The Mülliken and NBO charge distribution upon the surfaces of the TM-PIC₈₂F structures was measured in the range of +0.999 to +1.094 on iron atoms and +1.505 to +1.538 on magnesium atoms vs. −0.691 and −0.613 on nitrogen atoms. Comparison of E_g in these structures with that of the initial PIC₈₂F structure was displayed that because of chemisorption this data was decreased about 0.19–0.37 eV in A isomer, 0.21–0.22 eV in B isomer, and 0.05–0.13 eV in C isomer. Based on Froudakisʼs findings, the obtained results from E_g and the charge distribution; each three isomers of the Mg-PIC₈₂F structure can be considered as promising candidate for hydrogen storage. © 2026