A first-principles study on two-dimensional tetragonal samarium nitride as a novel photocatalyst for hydrogen production

Abstract

The prospect of using two-dimensional tetragonal samarium nitride (t-SmN) in photocatalytic applications is being reported. First principles calculations were performed in order to study structural, electronic, thermal and photocatalytic properties of the material. The phonon band structure and cohesive energy computed using density functional perturbation theory revealed dynamical stability of the monolayer. Ab-initio molecular dynamics (AIMD) simulations were carried out to check the thermal stability of the monolayer which pointed that the material is stable above 1000 K and chemically inert at room temperature. The electronic structure calculations revealed SmN as ferromagnetic semiconductor with a direct bandgap of 1:41 eV that predicts applications of the material in spintronics. The band alignment pointed towards suitability of band offsets for electrochemical reduction of water splitting at neutral pH. The optical properties indicated decent light-harvesting ability of the material from visible and ultraviolet regions of solar spectrum. The micro-mechanisms of water decomposition and photocatalytic hydrogen formation on the SmN monolayer are unraveled to confirm water splitting and hydrogen generation.

Keywords: SmN, Ab-initio calculations, Stability, Surface, Water splitting