Plasma-heteroatom-doped Ni-V-Fe trimetallic phospho-nitride as high-performance bifunctional electrocatalyst

Bi-functional electrocatalysts capable to simultaneously sustain hydrogen and oxygen evolution reactions (HER, OER) under industry-relevant conditions of hydrogen production by water electrolysis are highly desired. Here, we implement a new concept of plasma-enabled simultaneous N-P heteroatom doping to achieve the highly-competitive activity and stability of trimetallic Ni-V-Fe bi-functional electrocatalysts on a NiFe foam (N-NiVFeP/NFF), evidenced by the lower overpotentials for HER (79 mV) and OER (229 mV) to deliver a current density of 10 mA cm−2 (j10) in the 1.0 M KOH electrolyte. Meanwhile, the N-NiVFeP/NFF exhibits ultra-stable performances with a current density from 10 to 100 mA cm-2 for over 100 h. Specifically, the HER and OER performances are near to those of noble-metal based electrocatalysts in the high current density region (> j200), attributing to the rich active sites exposed on the formed heterointerfaces among Ni-V-Fe phospho-nitrides, the changed electronic structure, and increased conductivity with nitrogen doping.