Nitrogen doped CoP on ammoniated black phosphorus nanosheets enabling highly efficient hydrogen evolution electrocatalysis.

Developing a rational and cost-effective approach for designing highly-efficient and sustainable electrocatalysts is essential for clean and renewable hydrogen energy. Herein, we report nitrogen-doped CoP on two-dimensional ammoniated black phosphorus (BP) nanosheets (N-CoP/NH-BP) as novel and highly-active heterostructure electrocatalysts for the hydrogen evolution reaction (HER). Using the reactive defects on the BP nanosheets as the original sites under NH gas, N-doped CoP nanocrystals were grown on the surface of the BP nanosheets that were functionalized with NH groups at their edge. The N-CoP/NH-BP heterostructure exhibits low overpotentials of 90 and 246 mV at 10 and 200 mA cm, respectively, in an alkaline electrolyte. The excellent HER activity should be attributed to the synergistic effect between N-doped CoP and NH-functionalized BP, in which NH-BP, with its high electron mobility and hydrophilicity, accelerates the charge transfer and offers more active sites, moreover, N-doped CoP modulates the electronic structure of CoP for enhanced HER activity. This work not only provides a novel and effective electrocatalyst, but also opens up a straightforward strategy for the design of phosphorene-based electrocatalysts for highly efficient hydrogen evolution and beyond.