Construction of unique ternary composite MCNTs@CoSx@MoS2 with three-dimensional lamellar heterostructure as high-performance bifunctional electrocatalysts for hydrogen evolution and oxygen evolution reactions

Developing non-noble and high activity electrocatalysts is the key to electrocatalytic water-splitting. Recently, MoS 2 shows vast perspectives due to its excellent catalytic performance and chemical stability in acid condition. Herein, to expand its application in different environment, a unique ternary composite MCNTs@CoS x @MoS 2 comprising three-dimensional lamellar heterostructure supported by multiwalled carbon nanotubes was successfully prepared by a two-step solvothermal strategy and used in electrocatalytic field. As a bifunctional electrocatalyst, heterostructure MCNTs@CoS x @MoS 2 could catalyst HER with a small overpotential of 196 mV and low Tafel slope of 65 mV dec −1 in acid condition and exhibit outstanding OER performance with a low overpotential of 285 mV and small Tafel slope of 76 mV dec −1 in alkaline solution. Meanwhile, it displayed excellent durability both in an acid and alkaline solution. The remarkable electrochemical performance of MCNTs@CoS x @MoS 2 can be attributed to novel construction advantages and synergy of MCNTs, small CoS x nanoparticles and lamellar MoS 2 . This work can be extended to the design and preparation of a series of composite materials with the advantage of structural diversity.