Manipulating heterointerface to boost formation and desorption of intermediates for highly efficient alkaline hydrogen evolution.

ABSTRACT

Promoting water dissociation and H intermediate desorption play a pivotal role in achieving highly efficient hydrogen evolution reaction (HER) in alkaline media but remain a great challenge. Herein, we rationally develop a unique W-doped NiSx/Ni heterointerface as a favorable HER electrocatalyst which was directly grown on the Cu nanowire foam substrate (W-NiSx/Ni@Cu) by the electrodeposition strategy. Benefiting from the rational design of the interfaces, the electronic coupling of the W-NiSx/Ni@Cu can be efficiently modulated to lower the HER kinetic barrier. The obtained W-NiSx/Ni@Cu exhibits an enhanced HER activity with a low overpotential of 38 mV at 10 mA cm-2 and a small Tafel value of 27.5 mV dec-1, and high stability during HER catalysis. In addition, in-situ Raman spectra reveal that the Ni2+ active sites preferentially adsorb OH intermediate. The theoretical calculation confirms that the water dissociation is accelerated by the construction of W-NiSx/Ni heterointerface and H intermediate desorption can be also promoted by H spillover from S active sites in W-NiSx to Ni active sites in metal Ni. This work offers a valuable reference for rational designing heterointerface of electrocatalysts and provides an available method to accelerate the HER kinetics for the ampere-level current density under low overpotential.