Ab initio calculations and molecular dynamics simulation of H2 adsorption on CN3Be3+ cluster

Abstract

Hydrogen adsorption properties of the CN3Be3+ cluster have been studied using density functional theory and MP2 method with a 6–31++G** basis set. Five hydrogen molecules get adsorbed on the CN3Be3+ cluster with a hydrogen storage capacity of 10.98 wt%. Adsorption of three H2 molecules on one of the three Be atoms in a cluster is reported for the first time. It is due to the more positive charge on this Be atom than the remaining two. The average value for H2 adsorption energy in CN3Be3+ (5H2) complexes is 0.41 (0.43) eV/H2 at MP2 (wB97XD) level, which fits well within the ideal range. Adsorption energy from electronic structure calculations plays an important role in retaining the number of H2 molecules on a cluster during atom-centered density matrix propagation (ADMP) molecular dynamics (MD) simulations. According to ADMP-MD simulations, out of five H2 adsorbed molecules on CN3Be3+, four and two H2 molecules remain absorbed on CN3Be3+ cluster at 275 K and 350 K, respectively, during the simulation.