Exploring the structure and hydrogen storage capacity of CeHn0/+ clusters

Abstract

The unique 4f orbitals and abundant electronic energy levels of rare earth elements enable effective doping and modification to enhance hydrogen storage performance, making it an increasingly prominent focus of research. The structures of neutral and cationic CeH_n^0/+ (n = 2–20) clusters have been determined using the Crystal Structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method in conjunction with density functional theory (DFT). Interestingly, the CeH₁₃ and CeH₁₄⁺ exhibit remarkable stability in the doublet state with C_s and C_2v symmetry, respectively. The adsorption energy of CeH_n^0/+ (n = 2–20) suggests a preference for H atoms to chemically adsorb on Ce atoms. The analysis of molecular orbital composition reveals that the stability of both CeH₁₃ and CeH₁₄⁺ is attributed to the significant hybridization between the H 1s and Ce 4f orbitals. Both CeH₁₃ and CeH₁₄⁺ demonstrate significant hydrogen storage capacities, with values reaching 8.5 wt% and 9.1 wt%, respectively.