Carbides are commonly regarded as efficient hydrogen evolution reaction (HER) catalysts, but their poor oxygen evolution reaction (OER) catalytic activities seriously limit their practical application in overall water splitting. Here, vertically aligned porous cobalt tungsten carbide nanosheet embedded in N‐doped carbon matrix (Co6W6C@NC) is successfully constructed on flexible carbon cloth (CC) as an efficient bifunctional electrocatalyst for overall water splitting via a facile metal–organic framework (MOF) derived method. The synergistic effect of Co and W atoms effectively tailors the electron state of carbide, optimizing the hydrogen‐binding energy. Thus Co6W6C@NC shows an enhanced HER performance with an overpotential of 59 mV at a current density of −10 mA cm−2. Besides, Co6W6C@NC easily in situ transforms into tungsten actived cobalt oxide/hydroxide during the OER process, serving as OER active species, which provides an excellent OER activity with an overpotential of 286 mV at a current density of −10 mA cm−2. The water splitting device, by applying Co6W6C@NC as both the cathode and anode, requires a low cell voltage of 1.585 V at 10 mA cm−2 with the great stability in alkaline solution. This work provides a feasible strategy to fabricate bimetallic carbides and explores their possibility as bifunctional catalysts toward overall water splitting.

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Designing a state-of-the-art nonprecious oxygen evolution reaction (OER) electrocatalyst with ultralong stability under high current density (≥100 h under 1000 mA cm–2) is greatly desirable for the viable electrolysis of water. The synthesis of nanostructure catalysts is an effective method for improving the OER performance, but nanostructure-based catalysts are easily destroyed by mechanical force via the vigorous oxygen gas evolution process at a high current density. Herein, we present a facile strategy of N-anion and Fe-cation dual doping to construct a three-dimensional self-supported nickel selenide film-based catalyst via a one-step chemical vapor deposition process. The film exhibits outstanding OER activity with a small Tafel slope of 34.86 mV dec–1 and an overpotential of 267 mV at 100 mA cm–2 in 1 M KOH media. Impressively, the film-based catalyst can maintain this excellent catalytic activity over 100 h, even when operated at a high current density of 1 A cm–2, thus exhibiting the best reported OER stability under high current density so far. Further studies reveal that anion–cation co-doping can simultaneously modulate the electronic state and phase structure of nickel selenide, thereby promoting the in situ formation and transformation of oxygen-vacancy-rich amorphous OER active species and resulting in the superior OER performance of the film-based catalyst.

In alkaline media, the water-dissociation-related Volmer process always suppresses the hydrogen formation/ desorption process, which makes it challenging to develop non-noble-metal alkaline electrocatalysts with excellent catalytic activity. Here, we proposed a two-pronged strategy to simultaneously promote the kinetic process of both water dissociation and hydrogen desorption with the Co-doped WO 2 /amorphous Co x W hybrid electrocatalyst. Impressively, the optimized hybrid exhibits an outstanding hydrogen evolution reaction (HER) activity with the quite small Tafel slope of 19.77 mV dec −1 and ultralow overpotential of just 25 mV to reach a current density of 10 mA cm −2 in alkaline media. Both experiments and density functional theory calculations reveal that the top-level HER performance can be attributed to the cooperation of two different active components, in which the water molecule can easily be activated on the amorphous Co x W with low energy barrier (ΔG w = 0.46 eV), while hydrogen atoms can rapidly desorb from the Co-doped WO 2 with an optimal Gibbs free energy of hydrogen adsorption (ΔG H* = −0.06 eV). Also, the density functional theory calculation further confirms that the H* tends to combine with another H* via Tafel step rather than Heyrovsky step. The findings provide unique insights for the development of the state-of-the-art non-noble-metal HER electrocatalyst with a Pt-like kinetic behavior in alkaline media.

Zn‐N‐C possesses the intrinsic inertia for Fenton‐like reaction and can retain robust durability in harsh circumstance, but it is often neglected in oxygen reduction reaction (ORR) because of its poor catalytic activity. Zn is of fully filled 3d104s2 configuration and is prone to evaporation, making it difficult to regulate the electronic and geometric structure of Zn center. Here, guided by theoretical calculations, five‐fold coordinated single‐atom Zn sites with four in‐plane N ligands is constructed and one axial O ligand (Zn‐N4‐O) by ionic liquid‐assisted molten salt template method. Additional axial O not only triggers a geometry transformation from the planar structure of Zn‐N4 to the non‐planar structure of Zn‐N4‐O, but also induces the electron transfer from Zn center to neighboring atoms and lower the d‐band center of Zn atom, which weakens the adsorption strength of *OH and decreases the energy barrier of rate determining step of ORR. Consequently, the Zn‐N4‐O sites exhibit improved ORR activity and excellent methanol tolerance with long‐term durability. The Zn‐air battery assembled by Zn‐N4‐O presents a maximum power density of 182 mW cm−2 and can operate continuously for over 160 h. This work provides new insights into the design of Zn‐based single atom catalysts through axial coordination engineering.