DFT Study of Ca-adsorbed MoS2 Monolayer for Hydrogen Storage Application

Abstract

Surface metal adsorption on 2D structures is demonstrated to be an effective tool for improving hydrogen storage capacity. In the current work, the behavior of Ca atom adsorption on monolayer MoS 2 is studied and subsequently its hydrogen storage capacity is investigated computationally using van der Waals (vdW) revised Density Functional Theory. It is found that the Ca binds strongly with the MoS 2 monolayer without being clustered, leading to high hydrogen storage capacity. It is further shown that five hydrogen molecules to each Ca atom can be adsorbed with the average adsorption energy of 0.23eV per hydrogen molecule, indicating it to be a good choice for reversible adsorption/desorption of H 2 molecules at ambient conditions. It is revealed that hybridizations between s orbitals of H 2 and p orbitals of S are also responsible for adsorption mechanism, along with coulomb interactions. It is demonstrated that a steady and uniform high Ca coverage can be achieved without clustering and with enhanced binding energy which can be used as high hydrogen capacity storage system. Copyright