Fabrication of nitrogen-doped carbon on NiCoP electrocatalyst with flower-like structure for efficient hydrogen evolution reaction in alkaline solution

Abstract

The development of hydrogen evolution catalysts with low cost, high activity, and outstanding stability has become an urgent need. Herein, we reported a novel and effective strategy for the in situ growth of NiCoP nanoparticles encapsulated in ultrathin nitrogen-doped porous carbon on nickel foam (NiCoP@NC/NF). Compared with NiCoP/NF, the NiCoP@NC/NF presented a much larger electrochemically active surface area (ECSA) (1402.9 cm2 mg−1), more abundant intrinsic HER active sites and lower charge-transfer resistance, leading to superior catalytic activity. The as-prepared NiCoP@NC/NF electrode exhibited extremely low overpotential η10 (77 mV) and Tafel slope (62.1 mV dec−1) for HER in 1.0 M KOH as the electrolyte. Importantly, due to the thin nitrogen-doped carbon layer, NiCoP@NC/NF showed considerably enhanced stability under the harsh conditions of long-term reaction. Density functional theory (DFT) calculations have indicated that the nitrogen-doped carbon of NiCoP@NC/NF permitted moderate trapping of hydrogen atoms and easy desorption of the resulting H2. Such impressive HER performance of the hybrid electrocatalyst is mainly attributed to the collective effects of elemental doping engineering between NC and NiCoP, the enlarged surface area/exposed catalytic active sites, and the lower transfer resistance due to the nitrogen-doping carbon. The present work proposed a controllable and feasible strategy for synthesizing bimetallic phosphides with unique morphology and high HER performance.