Cobalt incorporation and MoS2–NiS2 heterostructure synergistic for improving full water electrolysis efficiency

Abstract

Designing a robust bifunctional water splitting catalyst at low cost is of great importance for water splitting. Herein, the in situ-generated MoS₂/NiS₂ nanosheet heterostructures by cobalt incorporation on carbon paper (Co–MoS₂/NiS₂/CP) are first obtained by applying a scalable chemical vapor vulcanization approach. Based on the synergistic effects of cobalt element doping and the construction of MoS₂/NiS₂ heterostructures, the much enhanced electrocatalytic performance for full water electrolysis is clearly revealed. In particular, the electronic structure of MoS₂/NiS₂ heterostructures was further effectively modified by cobalt incorporation along with the electron density of catalytic sites, which both promote the Volmer step to speed up alkaline hydrogen evolution reaction (HER) and optimize the oxygen-containing intermediate adsorption to enhance oxygen evolution reaction (OER). Consequently, Co–MoS₂/NiS₂/CP heterostructures presented low overpotentials (HER: η₁₀ = 109 mV; OER: η₁₀ = 323 mV) in the basic solution. Furthermore, Co–MoS₂/NiS₂/CP was designed as a two-electrode alkaline electrolytic configuration for full water electrolysis. This strategy experimentally illustrates the feasibility of designing a conventional electrocatalyst for water electrolysis via the cooperative effects of metal doping and heterostructured engineering.