In Situ Fabrication of a Nickel/Molybdenum Carbide-Anchored N-Doped Graphene/CNT Hybrid: An Efficient (Pre)catalyst for OER and HER.

Despite the recent promise of transition metal carbides as nonprecious catalysts for the hydrogen evolution reaction (HER), their extension to the oxygen evolution reaction (OER) to achieve the goal of overall water splitting remains a significant challenge. Herein, a new Ni/Mo _x C (MoC, Mo ₂ C) nanoparticle-supported N-doped graphene/carbon nanotube hybrid (NC) catalyst is developed via a facile, one-step integrated strategy, which can catalyze both the HER and OER in an efficient and robust manner. The catalyst affords low overpotentials of 162 and 328 mV to achieve a current density of 10 mA/cm ² for HER and OER, respectively, in alkaline medium, which either compares favorably or exceeds most of the Mo-based catalysts documented in the literature. It is believed that there is an electronic synergistic effect among Mo _x C, Ni, and NC, wherein a tandem electron transfer process (Ni → Mo _x C → NC) may be responsible for promoting the HER as well as OER activity. This work opens a new avenue toward the development of multicomponent, highly efficient but inexpensive electrocatalysts for overall water splitting.