Electrospun Co‐MoC Nanoparticles Embedded in Carbon Nanofibers for Highly Efficient pH‐Universal Hydrogen Evolution Reaction and Alkaline Overall Water Splitting

Abstract The construction of highly efficient and self‐supported electrocatalysts with abundant active sites for pH‐universal hydrogen evolution reaction (HER) and alkaline water splitting is significantly challenging. Herein, Co and MoC nanoparticles embedded in nitrogen‐doped carbon nanofibers (Co‐MoC/NCNFs) which display a bamboo‐like morphology are prepared by electrospinning followed by the carbonization method. The electrospun MoC possesses an ultrasmall size (≈5 nm) which can provide more active sites during electrocatalysis, while the introduction of Co greatly optimizes the electronic structure of MoC. Both endow the Co‐MoC/NCNFs with superior HER performances over a wide pH range, with low overpotentials of 86, 116, and 145 mV to achieve a current density of 10 mA cm −2 in alkaline, acidic, and neutral media, respectively. Additionally, the catalyst exhibits remarkable alkaline oxygen evolution reaction (OER) activity with an overpotential of 254 mV to reach 10 mA cm −2 . Density functional theory calculations confirm that electron transfer from Co to MoC regulates the adsorption free energy for hydrogen, thereby promoting HER. Moreover, an electrolyzer assembled with Co‐MoC/NCNFs requires only a cell voltage of 1.59 V at 10 mA cm −2 in 1 m KOH. This work opens new pathways for the design of high‐efficiency electrocatalysts for energy conversion applications.