Facile Route to Achieve Co@Mo2C Encapsulated by N-Doped Carbon as Efficient Electrocatalyst for Overall Water Splitting in Alkaline Media

The development of inexpensive, highly efficient and stable noble metal-free heterostructure bifunctional electrocatalysts is crucial for water electrolysis. Herein, a facile strategy is utilized by pyrolyzing the mixture containing ammonium molybdate tetrahydrate and zeolitic imidazolate framework-67 to achieve a product with Co nanoparticles as core and β-Mo2C embedded in N-doped carbon as a shell (Co@β-Mo2C-NC). The Co@β-Mo2C-NC-0.115 (quantity of Mo precursor) composite illustrates an overpotential (η10) of 188 and 330 mV for hydrogen and oxygen evolution reactions, respectively, and a cell voltage of 1.72 V is required for overall water splitting to attain a current density of 10 mA cm−2 in alkaline media. Remarkably, the Co@β-Mo2C-NC-0.115 catalyst exhibits excellent stability for continuous operation of 15 h chronopotentiometry and 25 h chronoamperometry measurements. The satisfactory electrocatalytic performance can be ascribed to the unique core–shell nanostructure, especially the synergistic effect between Co, β-Mo2C and N-doped carbon. These research findings speculate a straightforward strategy to fabricate MOF derived heterostructures with robust catalytic performance and wide applications in electrocatalysis.