Hydrogen encapsulation properties of heteroatoms doped fullerenes: A DFT study for potential hydrogen storage application

Abstract

The hydrogen storage properties of C 60 , As C 59 , Bi C 59 , N C 59 , and P C 59 , are assessed herein at DFT/m062x/LANL2DZ level of theory; a novel approach where the H 2 molecule is adsorbed onto the encapsulated region of the C 60 cage. After optimization, stable configurations were obtained for all systems with binding energy values of approximately 39 eV. Notably, Bi atom portrayed the highest binding to C 60 as a result of spatially localized 6p and 4p orbital of Bi and As, forming an overlap with 2p orbital of carbon. Among the interactions, H 2 -Bi-C 59 depicted increased electrical conductivity and high reactivity due to the low energy gap of 1.9538 eV. H 2 -N-C 59 follows this with an energy gap of 2.7356 eV. In contrast, the highest energy gap is exhibited by H 2 -C 59 interaction with an energy gap of 7.1022 eV showing heightened stability, minimal charge transfer, and low interaction strength . H 2 -As-C 59 and H 2 -Bi-C 59 promote chemisorption (−0.0656 and −0.0669 eV respectively) by providing more favorable sites for H 2 interaction. In contrast, H 2 -N-C 59 , H 2 -P-C 59, and H 2 -C 59 , N, and P dopants show weak interaction (borderline chemisorption) with values of −0.01162, −0.01162, and −0.1171 eV respectively. Negative ΔG 0 values were obtained for all the systems, indicating that hydrogen adsorption is spontaneous and thermodynamically feasible, while ΔH 0 suggests an exothermic reaction process in all systems. In conclusion, this study showcases the potential of As C 59 , Bi C 59 , N C 59 , and P C 59 surfaces as effective hydrogen storage materials compared to C 60 , ranking Bi-C 59 > As-C 59 > N-C 59 as the optimal surfaces in order of effectiveness, due to increased conductivity and favorable adsorption properties. • Hydrogen storage potential of C60 doped with Group 15 elements analyzed using DFT. • Impact of heteroatom doping on electronic and structural properties explored. • Feasibility of doped fullerenes for hydrogen encapsulation demonstrated. • Insights provided into the design of advanced materials for renewable energy storage.