Anchoring NiCo alloys onto N-doped carbon spheres for enhanced electrocatalytic hydrogen evolution reaction

Ni-ZIF-67 nanocrystals are hydrothermally grown on polydopamine (PDA) spheres, followed by pyrolysis to yield N-doped carbon sphere-supported NiCo alloy nanoparticles (NiCo@NCS). Systematic characterizations demonstrate that Ni doping is crucial for promoting the electrocatalytic activity toward hydrogen evolution reaction (HER). The NiCo@NCS catalyst exhibits high HER performance, achieving a low overpotential of 276 mV at 10 mA cm −2 , a favorable Tafel slope of 110 mV dec −1 , and exceptional stability. This performance enhancement originates from the synergistic coupling of homogeneously dispersed NiCo alloy nanoparticles, accelerated charge transfer kinetics, and ‌hierarchical pore structure.