NiCoP nanoparticles embedded in coal-based carbon nanofibers as self-supporting bifunctional electrocatalyst toward water splitting

The high activity and prolonged stability of bifunctional electrocatalysts are significant prerequisites for electrocatalytic water splitting. Recently, it has been proven that the performance of electrocatalysts can be elevated by optimizing components and constructing self-supporting electrodes. Herein, the well-proportioned NiCoP nanoparticles embedded in self-supporting coal-based carbon nanofibers (NiCoP@C-CNFs-2) are fabricated by electrospinning and pyrolysis process with the help of phytic acid and oxidized coal. The phytic acid not only chelates Ni and Co ions to disperse the active sites but serves as a green phosphorus source to prepare the well-proportioned NiCoP nanoparticles. Meanwhile, benefiting from coal-based carbon nanofibers with high electrical conductivity and excellent mechanical strength, the obtained self-supporting NiCoP@C-CNFs-2 is endowed with good bifunctional electrocatalytic activity and stability. The NiCoP@C-CNFs-2 severally provides overpotentials of 121 and 259 mV for HER and OER at 10 mA cm−2 in 1.0 M KOH electrolyte. Furthermore, an alkaline electrolyzer with NiCoP@C-CNFs-2 as bifunctional electrocatalysts requires 1.636 V voltage and maintains superior stability over 50 h at 10 mA cm−2. This work opens a reasonable avenue to design simple and efficient self-supporting carbon nanofibers electrocatalysts.