Well-aligned metal–organic framework array-derived CoS2 nanosheets toward robust electrochemical water splitting

Exploring high-efficiency and stable nonprecious bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is highly desirable but still challenging. Herein, we develop a versatile approach for the rational design and fabrication of highly open three-dimensional (3D) hierarchical architectures composed of two-dimensional (2D) CoS2 nanosheets grown on carbon cloth (CoS2 NS/CC) by vulcanizing well-aligned MOF-array precursors. Benefiting from the unique morphology with a high surface area, high density of active sites, and enhanced mass/electrolyte transfer, as well as facile release of the evolved gas, the as-synthesized CoS2 NS/CC exhibits superior catalytic performance and excellent durability for both the HER and OER. Furthermore, when used as a bifunctional electrocatalyst toward overall water splitting, a low cell voltage of 1.58 V is achieved at the current density of 10 mA cm−2 with long-term stability.