TMB2C (TM = Ti, V): 2D transition metal borocarbide monolayer with intriguing electronic, magnetic and electrochemical properties

Abstract

Designing two-dimensional materials with intriguing electronic and magnetic properties holds great potential for electronic and spintronic device application. By means of density functional theory calculations, we predicted a class of 2D MXene-like transition metal (TM) borides, TMB2C (TM = Ti, V, Cr, Mn, Fe) monolayer and their TMB2CX analogues by terminating various functional groups (X = H, O, F, S). The results show that two TMB2C monolayers at TM = V and Cr are thermodynamically stable with lager cohesive energies and positive frequencies in the phonon dispersion bands. TiB2C is antiferromagnetic (AFM) semiconductor and VB2C is ferromagnetic (FM) half metal with a high Curie temperature (Tc) of ∼ 580 K. Moreover, TiB2CXs and VB2CXs (X = H, O, F, S) show better mechanical stability and distinct electronic and magnetic properties with semiconductor-(half) metal and FM-AFM transform. Interestingly, VB2CF is revealed to exhibit excellent hydrogen evolution reaction (HER) performance with an adsorption Gibbs free energy for H atom close to zero (ΔGH* = 0.03 eV). The high stability and excellent properties make TMB2C(X) monolayer a promising candidate for potential spintronic and electrocatalytic application.