P non-metal doping induced surface charge redistribution of VS2 for strengthening hydrogen evolution activity

This report reveals that the hydrogen evolution activity of VS 2 can be effectively strengthened by inducing the surface charge redistribution of VS 2 via P non-metal doping. The XRD, TEM, GPA, EDS and XPS characterizations confirm that the P atoms are successfully doped into the VS 2 /CC matrix by substituting S atoms, resulting in lattice tensile strain and charge redistribution. The optimal P-doped VS 2 on carbon cloth (P-VS 2 /CC) exhibits a low overpotential of 274 mV at − 50 mA cm −2 and a small Tafel slope of 65.4 mV dec -1 , much lower than those of VS 2 /CC counterpart (622 mV and 120.1 mV dec −1 , respectively). Moreover, the P-VS 2 /CC delivers a long-term stability for 55 h without decay at 10 mA cm −2 , outperforming the VS 2 /CC. Density functional theory calculations suggest that P doping can induce the charge transfer from S and V to nearby P atoms, resulting in the decrease of hydrogen adsorption free energy at the S and V sites and the increase of total density of states at the Fermi level, thus far super hydrogen evolution activity. This work provides a hopeful new route for strengthening the HER activity of VS 2 , and offers a new perspective for developing advanced transition-metal chalcogenides electrocatalysts.