NiS–MoS2 hetero-nanosheet array electrocatalysts for efficient overall water splitting

Abstract

Coupling two-dimensional earth-abundant element based electroactive species with three-dimensional carbon substrates is a promising but highly challenging strategy to prepare highly active, robust and eco-friendly electrocatalysts for sustainably generating hydrogen and oxygen from water splitting. Here we report a facile one-step collaborative growth method to directly construct NiS–MoS₂ hetero-nanosheet arrays on carbon cloth (NiS–MoS₂ HNSAs/CC) by introducing sodium dodecyl sulfate as a surfactant together with Ni, Mo and S sources. Benefiting from the well-exposed electroactive sites, fast transport of catalysis-relevant species and strong synergistic catalytic effect between NiS and MoS₂, the as-prepared NiS–MoS₂ HNSAs/CC exhibits excellent electrocatalytic performance for water splitting in 1 mol L⁻¹ KOH, presenting an overpotential of 106 mV for the hydrogen evolution reaction and 203 mV for the oxygen evolution reaction at 10 mA cm⁻², and superior kinetics for them with a Tafel slope of 56.7 and 77.4 mV dec⁻¹, respectively. Moreover, a current density of 10 mA cm⁻² at a low cell voltage of 1.54 V for overall water splitting could be achieved along with an excellent stability for at least 24 h. This simple strategy might also be applied to assemble other kinds of active species on different inert substrates, providing new insight into the design and development of high-performance electrocatalysts and other electrochemical devices.