Template-Directed Bifunctional Dodecahedral CoP/CN@MoS2 Electrocatalyst for High Efficient Water Splitting

Abstract

Designing high efficient and noble metal-free bifunctional electrocatalysts for both hydrogen and oxygen generation is still critical and challenged. In this study, hierarchical dodecahedral-structured CoP/CN@MoS2 is prepared through a two-step calcination treatment and a solvothermal approach. The metal-organic framework of ZIF-67 is chosen to serve as the template and for providing Co sources, in which ZIF-67 is first transformed to Co nanoparticles embedded in nitrogen-doped carbon polyhedrons and then transformed to CoP/CN. MoS2 nanosheets are further grown on the surface of dodecahedral-structured CoP/CN with a solvothermal method. Benefiting from the synergistic coupling effect of CoP and MoS2 and the nitrogen-doped carbon matrix, advanced hydrogen evolution reaction (HER) both in acid and alkaline solution as well as splendid oxygen evolution reaction (OER) performance in alkaline aqueous were achieved. Moreover, the coupling effect of CoP/CN and MoS2 is disclosed theoretically by density functional theory calculations to validate the increased HER activity. The as-prepared hybrid CoP/CN@MoS2 not only exhibits decent HER activity in acidic (η10 = 144 mV) and alkaline solutions (η10 = 149 mV), but also exhibits splendid OER activity (η10 = 289 mV) in 1.0 M KOH. This work represents a solid step toward boosting the electrocatalytic kinetics of nonprecious catalysts.