Mg-decorated CN monolayer with enhanced hydrogen storage

Abstract

Current hydrogen storage confronts safety and high energy cost challenges. Solid-state hydrogen storage provides an efficient pathway with lower cost and pressure conditions. Here, we perform density functional theory (DFT) calculations measuring the hydrogen storage properties of Mg-decorated CN monolayer. 8Mg@CN structure is confirmed based on energetic and geometric criteria and it can absorb up to 40 H2 molecules, achieving a high gravimetric density of 8.92 wt% over the US Department of Energy (DOE) target. The polarized H2 molecules are proven to be physiosorbed on Mg atoms to guarantee desorption. The electronic properties are studied to illustrate the electrostatic attractions between the H2 molecules and the Mg-decorated CN monolayer. Moreover, the desorption temperatures and adsorption pressures are calculated to illustrate the reversibility of hydrogen storage applications on 8Mg@CN. These results indicate 8Mg@CN could be a promising candidate for hydrogen storage with potentially reversible application.