Effect of edge structure on the activity for hydrogen evolution reaction in MoS2 nanoribbons

Abstract

Density functional theory (DFT) was carried out to investigate the effect of edge structure on the catalytic activity and electronic properties of MoS2 nanoribbons for hydrogen evolution reaction (HER). There are two stable configurations of MoS2 nanoribbons, MoS2NR-L and MoS2NR-R, with an energy barrier of 0.035eV. Four hydrogen adsorbed configurations are obtained by adsorbing the hydrogen atom at the different adsorption sites of two configurations. By calculating the Gibbs free energy and exchange current densities, it is found that these four adsorbed configurations have varied catalytic activity for HER, which demonstrates that location of edge atoms has significantly effect on the catalytic activity for HER. The optimization in HER activities originates from the suitable binding between hydrogen atom and S atom, corresponding to that Gibbs free energy is close to zero. Our results signify that the edge structures play a key role on the HER activity in MoS2 nanoribbons.