Magnetic Co₂Si monolayer with high performance hydrogen evolution reaction: a first-principle prediction

In this article, we have investigated the electronic structure of Co₂Si monolayer by first-principle calculations, and the phonon spectrum calculation results do not show any imaginary frequencies, indicating its stable existence. The calculation of electronic structure shows that there are two nodal loops centered on gamma in the K_z=0 plane, and these two nodal loops still exist considering the coupling of spin and orbitals. The calculation results of free energy indicate that Co₂Si monolayer is very suitable as a catalyst for hydrogen evolution reactions. Its Gibbs free energy for adsorbing hydrogen atom is as low as -0.067 eV, which is superior to many other catalytic materials and comparable to Pt. In addition, when electron or hole doping is carried out, its Gibbs free energy for hydrogen absorption changes accordingly. These results indicate that Co₂Si monolayer has the potential to become a high-performance and inexpensive catalyst for hydrogen evolution reactions.