Transition metal improved the dehydrogenated capacity, electronic and optical properties of the layered V2C MXene for hydrogen evolution reaction

Abstract

Although the 2D layered V₂C MXene is an attractive electrocatalyst for hydrogen evolution reaction (HER) due to the excellent conductivity, low electronic transfer resistance and low overpotential, the dehydrogenation mechanism of 2D layered V₂C MXene is entirely unknow. To understand and improve the dehydrogenated capacity of V₂C MXene electrocatalyst, the influence of transition metals (TM=Ti, Zn and Ru) on the dehydrogenated capacity, electronic and optical properties of V₂C electrocatalyst is studied by using the ab-initio calculations. The result shows that the calculated hydrogen dissociation energy of V₂C MXene is 1.646 eV. Naturally, the dehydrogenated capacity of V₂C is determined by the bond strength of V-C bond at the V-C-V-C layered structure. In particular, these doped transition metals reduce H desorption energy cost compared to V₂C MXene because these transition metals weaken the electronic interaction between V and C atoms, and between V and H atoms, which is beneficial to H desorption in V₂C. In addition, the V₂C and TM-doped V₂C show ultraviolet properties. Compared to V₂C, the doped transition metal results in the adsorption coefficient moved from the ultraviolet region to the light visible region. Therefore, we believe that these transition metals are better catalysts to improve the dehydrogenated behavior of V₂C electrocatalyst for hydrogen evolution reaction (HER).