Binary Ni-W metal sulfides with polyhedral nanostructures towards efficient hydrogen evolution

Abstract

Designing multi-transition metal-based sulfides holds promising in alkaline water electrolysis, whereas selecting suitable, cheap candidates and facile building strategy remain challengeable. Herein, based on previous theory of combining 3d-transition metal (Ni) with non-3d-transition metal (W) to lower hydrogen adsorption energy barriers, we develop an indirect access to NiW sulfides supported by nickel foam (NiWO-S/NF) with polyhedral nanostructures. The unique structure not only provides the large surface areas for exposing abundant active sites, but also improves the contact between catalyst/interface and facilitates the mass or charge transportation. Besides, the binary metals are supposed to generate synergistic effect to boost hydrogen evolution reaction (HER) properties of NiWO-S/NF via sulfurization method. Both physical characterization and DFT calculation prove that the electron transport, water dissociation capability and hydrogen adsorption of NiWO-S/NF are finely tuned benefited from the sulfurization, thus greatly expediting HER kinetics. Furthermore, NiWO-S/NF demonstrates high electrocatalytic performances with structural stability in long-term HER process. Therefore, the two-step building of binary transition metal sulfide nanostructures may be provide new method for applications of various transition metal materials with unique architecture and high efficiency in alkaline HER.