Cobalt doping engineering of MoC-Mo₂N heterostructures in porous carbon nanofibers for enhanced hydrogen evolution

The development of inexpensive, high-performance electrocatalysts is critical for efficient water electrolysis. Transition metal carbides have been demonstrated to be highly promising HER electrocatalysts. In this work, we implemented nanostructural design and electronic modulation strategies to optimize transition metal carbide electrocatalysts. Cobalt-doped MoC-Mo₂N heterostructures encapsulated in porous carbon nanofibers (Co/MoC-Mo₂N@pCNFs) were synthesized as HER electrocatalysts in a one-step strategy. Combined experimental results and DFT calculations revealed that cobalt doped in the transition metal-based heterostructures significantly enhances HER performance. The Co/MoC-Mo₂N@pCNFs catalyst exhibited low overpotentials of 95 mV in alkaline and 115 mV in acidic medium at a current density of 10 mA cm^-2, with long-term stability of 40 h and 35 h, respectively. It is superior to many reported transition metal carbide or nitride electrocatalysts. This work provides a valuable reference for the development of efficient and stable transition metal carbide and nitride electrocatalysts.