Theoretical study on geometric structures and hydrogen storage in anionic CeH[formula omitted] ([formula omitted] = 2–20) nanoclusters

Abstract

The geometric structures of anionic CeHn− (n = 2–20) clusters are obtained using crystal structure analysis by particle swarm Optimization(CALYPSO) and density functional theory(DFT). The SDD basis set for Ce atom and the all electron 6-311G ＋ ＋ (D, P) basis set for H atom are set respectively, and the lower-energy isomers in each size for CeHn− (n = 2–20) clusters are re-optimized at the B3LYP level. The photoelectron spectroscopy(PES) for the global minimum of anionic CeHn− (n = 2–20) clusters have been simulated using the Time-Dependent Density Function Theory(TD-DFT) method to determine the authenticity of all the lowest-energy structures obtained. The anionic CeH10− cluster with C2v point group symmetry and an excellent hydrogen storage capacity of 6.7 wt% has been discovered. Chemical bond analysis shows that the internal stability of anionic CeH10− cluster is primarily affected by the interaction between Ce 4f orbital and H 1s orbital, which is formed σ bond at the larger HLG of 4.78 eV. Furthermore, anionic CeH10− cluster has high hydrogen storage capacity, large adsorption energy and good stability, which is expected to be a new nanometer hydrogen storage material. The present work provides guidance for the future synthesis and design of new rare earth(RE) hydrogen storage nanomaterials.