Encapsulation of Ni 3 Fe Nanoparticles in N‐Doped Carbon Nanotube–Grafted Carbon Nanofibers as High‐Efficiency Hydrogen Evolution Electrocatalysts

The exploration of cost‐effective yet high‐efficiency inexpensive electrocatalysts for the hydrogen evolution reaction (HER) is of critical significance for future renewable energy conversion technologies. A feasible electrospinning strategy to construct a novel 1D hierarchical nanoarchitecture comprising Ni 3 Fe nanoalloy‐encapsulated carbon nanotubes grown onto N‐doped carbon nanofibers (abbreviated as Ni 3 Fe@N‐C NT/NFs) is demonstrated here. Benefiting from the abundant firmly immobilized Ni 3 Fe nanoparticles for catalytic sites and hierarchical fibrous nanostructures for effective electron transport and mass diffusion, the resultant Ni 3 Fe@N‐C NT/NFs display an extraordinary HER activity with a low overpotential of 72 mV to reach a current density of 10 mA cm −2 in KOH medium and a remarkable stability for 40 000 s. Theoretical studies corroborate that the resultant Ni 3 Fe@N‐C NT/NFs exhibit a favorable Gibbs free energy of hydrogen adsorption (Δ G H* = −0.14 eV), further manifesting their superior HER activity. The present work will advance the development of highly efficient nonprecious electrocatalysts for energy conversion.