Exploring effects of strain on newly synthesised two-dimensional polyaramid for hydrogen storage using DFT

Abstract

Using Density Functional Theory, we have explored the hydrogen storage potential of a newly synthesised polymeric material, 2dpa (Two-dimensional polyaramid). Pristine 2dpa is not a good medium for hydrogen storage at ambient temperatures because it adsorbs hydrogen molecules via van der Waals interactions. The adsorption energy of hydrogen molecules, on the other hand, can be increased by doping or decorating metal atoms on the 2dpa monolayer. But, because of oxygen interference in hydrogen adsorption and metal atom clustering, the doping and decorating processes are difficult. Thus, we investigated the hydrogen storage capacity of 2dpa monolayers in the presence of tensile and compressive strain. Though the tensile strain does not give any chances for storage, at 4 % biaxial compressive strain, a 2dpa unit cell can adsorb 10 H2 molecules with a binding energy of -0.24 eV and weight% 6.9 meeting the conditions set by DoE. The desorption temperature is 209.73 K at 12bar indicating that the adsorption is reversible. The interaction of 2dpa and hydrogen atom orbitals, as well as the charge transfer process, has been examined using the partial density of states and surface charge density plots. The stability of the media is confirmed using AIMD simulationsand Phonopy calculations.