Sandwich‐Like Nanocomposite of CoNiOx/Reduced Graphene Oxide for Enhanced Electrocatalytic Water Oxidation

The development of cost‐effective and high‐performance electrocatalysts for oxygen evolution reaction (OER) is essential for sustainable energy storage and conversion processes. This study reports a novel and facile approach to the hierarchical‐structured sheet‐on‐sheet sandwich‐like nanocomposite of CoNiO _x /reduced graphene oxide as highly active electrocatalysts for water oxidation. Notably, the as‐prepared composite can operate smoothly both in 0.1 and 1.0 m KOH alkaline media, displaying extremely low overpotentials, fast kinetics, and strong durability over long‐term continuous electrolysis. Impressively, it is found that its catalytic activity can be further promoted by anodic conditioning owing to the in situ generation of electrocatalytic active species (i.e., metal hydroxide/(oxy)hydroxides) and the enriched oxygen deficiencies at the surface. The achieved ultrahigh performance is unmatched by most of the transition‐metal/nonmetal‐based catalysts reported so far, and even better than the state‐of‐the‐art noble‐metal catalysts, which can be attributed to its special well‐defined physicochemical textural features including hierarchical architecture, large surface area, porous thin nanosheets constructed from CoNiO _x nanoparticles (≈5 nm in size), and the incorporation of charge‐conducting graphene. This work provides a promising strategy to develop earth‐abundant advanced OER electrocatalysts to replace noble metals for a multitude of renewable energy technologies.     

Constructing Conductive Interfaces between Nickel Oxide Nanocrystals and Polymer Carbon Nitride for Efficient Electrocatalytic Oxygen Evolution Reaction

Combining transition metal oxide catalysts with conductive carbonaceous material is a feasible way to improve the conductivity. However, the electrocatalytic performance is usually not distinctly improved because the interfacial resistance between metal oxides and carbon is still large and thereby hinders the charge transport in catalysis. Herein, the conductive interface between poorly conductive NiO nanoparticles and semi‐conductive carbon nitride (CN) is constructed. The NiO/CN exhibits much‐enhanced oxygen evolution reaction (OER) performance than corresponding NiO and CN in electrolytes of KOH solution and phosphate buffer saline, which is also remarkably superior over NiO/C, commercial RuO₂, and mostly reported NiO‐based catalysts. X‐ray photoelectron spectroscopy and extended X‐ray absorption fine structure spectrum reveal that a metallic Ni–N bond is formed between NiO and CN. Density functional theory calculations suggest that NiO and CN linked by a Ni–N bond possess a low Gibbs energy for OER intermediate adsorptions, which not only improves the transfer of charge but also promotes the transmission of mass in OER. The metal–nitrogen bonded conductive and highly active interface pervasively exists between CN and other transition metal oxides including Co₃O₄, CuO, and Fe₂O₃, making it promising as an inexpensive catalyst for efficient water splitting.     

Superaerophobic Electrode with Metal@Metal‐Oxide Powder Catalyst for Oxygen Evolution Reaction

A stable and highly active oxygen evolution reaction (OER) electrode is the key for fast and robust O₂ production, which is one of the essential points for various kinds of energy conversion systems, such as water splitting, lithium‐O₂ battery and artificial photosynthesis. Here, superaerophobic electrodes with metal@metal‐oxide powder catalysts are shown, which demonstrate high and stable OER activity. The active‐site‐density of metal@metal‐oxide catalysts is increased over one order of magnitude than those of pure metal oxides due to the large enhancement of electrical conductivity, revealing the substantial enhancement of electrochemical OER kinetics. Furthermore, the superaerophobic property of electrodes is favorable for fast O₂ desorption, which improves electrochemical active surface area (EASA) during OER. The superaerophobic electrode with metal@metal‐oxide powder catalysts provides the new insight for increase of active‐site‐density and EASA simultaneously, which are the key factors to determine the activity of OER electrode.     

High‐Performance Metal‐Free Nanosheets Array Electrocatalyst for Oxygen Evolution Reaction in Acid

Development of low cost electrocatalysts with outstanding catalytic activity and stability for oxygen evolution reaction (OER) in acid is a major challenge to produce hydrogen energy from water splitting. Herein, a novel metal‐free electrocatalyst consisting of a oxygen‐functionalized electrochemically exfoliated graphene (OEEG) nanosheets array is reported. Benefitting from a vertically aligned arrays structure and introducing oxygen functional groups, the metal‐free OEEG nanosheets array exhibits superior electrocatalytic activity and stability toward OER with a low overpotential of 334 mV at 10 mA cm^?2 in acidic electrolyte. Such a high OER performance is thus far the best among all previously reported metal‐free carbon‐based materials, and even superior to commercial Ir/C catalysts (420 mV at 10 mA cm^?2) in acid. Characterization results and electrochemical measurements identify the COOH species in the OEEG acting as active sites for acidic OER, which is further supported by atomic‐scale scanning transmission electron microscopy imaging and electron energy‐loss spectroscopy. Density functional theory calculations reveal that the reaction pathway of dual sites that is mixed by zigzag and armchair edges (COOH‐zig‐corner) is better than the pathway of single site.     

Unveiling Role of Sulfate Ion in Nickel-Iron (oxy)Hydroxide with Enhanced Oxygen-Evolving Performance

The rational design of effective catalysts for sluggish oxygen evolution reactions (OERs) is desired but challenging. Nickel-iron (NiFe) (oxy)hydroxides are promising pre-electrocatalysts for alkaline OER. However, OER performances are limited by the slow reconstruction process to generate active species of high-valance NiFe oxyhydroxides. In this work, a sulfate ion (SO₄²⁻) modulated strategy is developed to boost the OER activity of NiFe (oxy)hydroxide by accelerating the electrochemical reconstruction of pre-catalyst and stabilizing the reaction intermediate of OOH* during OER. The SO₄²⁻ decorated NiFe (oxy)hydroxide catalyst (NF-S0.15) is fabricated via scalable anodization of NiFe foam in a thiourea-dissolved electrolyte. The experimental and theoretical investigations demonstrate the dual effect of SO₄²⁻ on improving OER performances. SO₄²⁻ leaching is favorable for the electrochemical reconstruction to form active NiFeOOH under OER condition. Simultaneously, the residual SO₄²⁻ adsorbed on surface can stabilize the intermediate of OOH*, and thus enhance the OER performances. As expected, NF-S0.15 delivers an ultralow overpotential of 234 mV to reach the current density of 50 mA cm⁻², a fast OER kinetics (27.7 mV dec⁻¹), and a high stability for more than 100 h. This unique insights into anionic modification could inspire the development of advanced electrocatalysts for efficient OER.     

Hybrid 2D Dual‐Metal–Organic Frameworks for Enhanced Water Oxidation Catalysis

Metal–organic frameworks (MOFs) and MOF‐derived nanostructures are recently emerging as promising catalysts for electrocatalysis applications. Herein, 2D MOFs nanosheets decorated with Fe‐MOF nanoparticles are synthesized and evaluated as the catalysts for water oxidation catalysis in alkaline medium. A dramatic enhancement of the catalytic activity is demonstrated by introduction of electrochemically inert Fe‐MOF nanoparticles onto active 2D MOFs nanosheets. In the case of active Ni‐MOF nanosheets (Ni‐MOF@Fe‐MOF), the overpotential is 265 mV to reach a current density of 10 mA cm^?2 in 1 m KOH, which is lowered by ≈100 mV after hybridization due to the 2D nanosheet morphology and the synergistic effect between Ni active centers and Fe species. Similar performance improvement is also successfully demonstrated in the active NiCo‐MOF nanosheets. More importantly, the real catalytic active species in the hybrid Ni‐MOF@Fe‐MOF catalyst are unraveled. It is found that, NiO nanograins (≈5 nm) are formed in situ during oxygen evolution reaction (OER) process and act as OER active centers as well as building blocks of the porous nanosheet catalysts. These findings provide new insights into understanding MOF‐based catalysts for water oxidation catalysis, and also shed light on designing highly efficient MOF‐derived nanostructures for electrocatalysis.     

Phosphorus‐Doped Perovskite Oxide as Highly Efficient Water Oxidation Electrocatalyst in Alkaline Solution

Developing cost‐effective and efficient electrocatalysts for oxygen evolution reaction (OER) is of paramount importance for the storage of renewable energies. Perovskite oxides serve as attractive candidates given their structural and compositional flexibility in addition to high intrinsic catalytic activity. In a departure from the conventional doping approach utilizing metal elements only, here it is shown that non‐metal element doping provides an another attractive avenue to optimize the structure stability and OER performance of perovskite oxides. This is exemplified by a novel tetragonal perovskite developed in this work, i.e., SrCo_0.95P_0.05O_{3– δ} (SCP) which features higher electrical conductivity and larger amount of O₂ ^2?/O^? species relative to the non‐doped parent SrCoO_{3– δ} (SC), and thus shows improved OER activity. Also, the performance of SCP compares favorably to that of well‐developed perovskite oxides reported. More importantly, an unusual activation process with enhanced activity during accelerated durability test (ADT) is observed for SCP, whereas SC delivers deactivation for the OER. Such an activation phenomenon for SCP may be primarily attributed to the in situ formation of active A‐site‐deficient structure on the surface and the increased electrochemical surface area during ADT. The concept presented here bolsters the prospect to develop a viable alternative to precious metal‐based catalysts.     

Ligand and Anion Co-Leaching Induced Complete Reconstruction of Polyoxomolybdate-Organic Complex Oxygen-Evolving Pre-Catalysts

The coordination compounds in the oxygen evolution reaction (OER) have been researched extensively. However, their poor durability (mostly < 100 h) and controversial reconstruction mechanism restrict their practical applications. Herein, a new-type polyoxomolybdate-organic complex (POMo) via wet-chemistry synthesis with fixed coordination between metal centers (Ni²⁺ and [Mo₈O₂₆]⁴⁻) and 2-Methylimidazole ligand is introduced. After introducing iron, a series of Fe-doped Ni-POMo with porous and amorphous structures are fabricated. These features accelerate the diffusion-leaching processes of ligands and anions, resulting in rapid and complete phase reconstruction during alkaline OER. As a result, nickel-iron (oxy)hydroxides with rich vacancies and poly-/low-crystalline features are in situ generated through dissolution-redeposition, and serve as the OER-active species. The optimized Fe_0.052Ni-POMo array pre-catalyst has excellent activity and sustains ultrastable catalysis for 545 h. The complete reconstruction of POMo enables high catalytic durability (230 h) and stable active phase under realistic conditions (30 wt% KOH, 60.9 °C). Accordingly, the completely reconstructed catalysts with unique structures and ultrastable catalysis have the potential to be applied in industry.     

Non‐Noble‐Metal‐Based Electrocatalysts toward the Oxygen Evolution Reaction

The development of low‐cost, high‐efficiency, and robust electrocatalysts for the oxygen evolution reaction (OER) is urgently needed to address the energy crisis. In recent years, non‐noble‐metal‐based OER electrocatalysts have attracted tremendous research attention. Beginning with the introduction of some evaluation criteria for the OER, the current OER electrocatalysts are reviewed, with the classification of metals/alloys, oxides, hydroxides, chalcogenides, phosphides, phosphates/borates, and other compounds, along with their advantages and shortcomings. The current knowledge of the reaction mechanisms and practical applications of the OER is also summarized for developing more efficient OER electrocatalysts. Finally, the current states, challenges, and some perspectives for non‐noble‐metal‐based OER electrocatalysts are discussed.     

Defect‐Rich Ni3FeN Nanocrystals Anchored on N‐Doped Graphene for Enhanced Electrocatalytic Oxygen Evolution

Owing to their unique optical, electronic, and catalytic properties, metal nitrides nanostructures are widely used in optoelectronics, clean energy, and catalysis fields. Despite great progress has been achieved, synthesis of defect‐rich (DR) bimetallic nitride nanocrystals or related nanohybrids remains a challenge, and their electrocatalytic application for oxygen evolution reaction (OER) has not been fully studied. Herein, the DR‐Ni₃FeN nanocrystals and N‐doped graphene (N‐G) nanohybrids (DR‐Ni₃FeN/N‐G) are fabricated through temperature‐programmed annealing and nitridation treatment of NiFe‐layered double hydroxides/graphene oxide precursors by controlling annealing atmosphere. In the nanohybrids, the DR‐Ni₃FeN nanocrystals are anchored on N‐G, and mainly show twin crystal defects besides ≈10% of stacking faults. Such nanohybrids can efficiently catalyze OER in alkaline media with a small overpotential (0.25 V) to attain the current density of 10 mA cm^?2 and a high turnover frequency (0.46 s^?1), superior to their counterparts (the nearly defect‐free Ni₃FeN/N‐G), commercial IrO₂, and the‐state‐of‐art reported OER catalysts. Except for the superior activity, they show better durability than their counterparts yet. As revealed by microstructural, spectroscopic, and electrochemical analyses, the enhanced OER performance of DR‐Ni₃FeN/N‐G nanohybrids originates from the abundant twin crystal defects in Ni₃FeN active phase and the strong interplay between DR‐Ni₃FeN and N‐G.     

Constructing Electrocatalysts with Composition Gradient Distribution by Solubility Product Theory: Amorphous/Crystalline CoNiFe-LDH Hollow Nanocages

Transition-metal based layered doubled hydroxides (LDH) as oxygen evolution reaction (OER) catalysts have attracted tremendous research interests. However, it is still a great challenge to strengthen the intrinsic activity of LDH. Herein, hollow CoNiFe-LDH nanocages with amorphous/crystal phase and element gradient distribution are successfully constructed through the coordinated etching and precipitation process. Utilizing the difference of solubility product constants among transition metal cations to generate the gradient distribution effect in nanocages is proposed for the first time. The distinctive element gradient distribution in hollow CoNiFe-LDH nanocages results in the composition gradient, which can provide the heterojunctions effect and play an important role in regulating morphology and electronic structure. Density functional theory calculations disclose that the synergistic effect between elements significantly regulates the electron density and enhances the conductivity. When employed as OER electrocatalysts, it exhibits a very competitive overpotential of 257 mV at 10 mA cm⁻² combined with a low Tafel slope of 31.4 mV dec⁻¹. This work represents a promising strategy to fabricate highly efficient OER catalysts for electrochemical water splitting and provides new opportunities to understand the promotion mechanism of intrinsic activity.     

High-Density Atomic Fe–N4/C in Tubular,Biomass-Derived,Nitrogen-Rich Porous Carbon as Air-Electrodes for Flexible Zn–Air Batteries

Developing low-cost single-atom catalysts (SACs) with high-density active sites for oxygen reduction/evolution reactions (ORR/OER) are desirable to promote the performance and application of metal–air batteries. Herein, the Fe nanoparticles are precisely regulated to Fe single atoms supported on the waste biomass corn silk (CS) based porous carbon for ORR and OER. The distinct hierarchical porous structure and hollow tube morphology are critical for boosting ORR/OER performance through exposing more accessible active sites, providing facile electron conductivity, and facilitating the mass transfer of reactant. Moreover, the enhanced intrinsic activity is mainly ascribed to the high Fe single-atom (4.3 wt.%) loading content in the as-synthesized catalyst.Moreover, the ultra-high N doping (10 wt.%) can compensate the insufficient OER performance of conventional Fe N C catalysts. When as-prepared catalysts are assembled as air-electrodes in flexible Zn–air batteries, they perform a high peak power density of 101 mW cm⁻², a stable discharge–charge voltage gap of 0.73 V for >44 h, which shows a great potential for Zinc–air battery. This work provides an avenue to transform the renewable low-cost biomass materials into bifunctional electrocatalysts with high-density single-atom active sites and hierarchical porous structure.     

Physically Adsorbed Metal Ions in Porous Supports as Electrocatalysts for Oxygen Evolution Reaction

Developing highly efficient and earth‐abundant electrocatalysts for the oxygen evolution reaction (OER) is significantly important for water‐splitting. Here, for the first time it is reported that the physically adsorbed metal ions (PAMI) in porous materials can be served as highly efficient OER electrocatalysts, which provides a universal PAMI method to develop electrocatalysts. This PAMI method can be applied to almost all porous supports, including graphene, carbon nanotubes, C₃N₄, CaCO₃, and porous organic polymers and all the systems exhibit excellent OER performance. In particular, the as‐synthesized Co_0.7Fe_0.3CB exhibits a small overpotential of 295 mV and 350 mV at the current density of 10 mA cm^?2 and 100 mA cm^?2, respectively, which exceeds commercial 40 wt% IrO₂/CB and most reported non‐noble metal‐based OER catalysts. Moreover, the mass activity of Co_0.7Fe_0.3CB reaches 643.4 A g^?1 at the overpotential of 320 mV, which is nearly 4.7 times higher than that of 40 wt% IrO₂/CB. In addition, the advanced ex situ and in situ synchrotron X‐ray characterizations are carried out to unravel the PAMI synthetic process. In short, this PAMI method will break the conversional understanding, i.e., the most OER catalysts are synthesized chemically, because the new PAMI method does not require any chemical synthesis, which therefore opens a new avenue for the development of OER electrocatalysts.     

Nanoporous Nitrogen‐Doped Graphene Oxide/Nickel Sulfide Composite Sheets Derived from a Metal‐Organic Framework as an Efficient Electrocatalyst for Hydrogen and Oxygen Evolution

Engineering of controlled hybrid nanocomposites creates one of the most exciting applications in the fields of energy materials and environmental science. The rational design and in situ synthesis of hierarchical porous nanocomposite sheets of nitrogen‐doped graphene oxide (NGO) and nickel sulfide (Ni₇S₆) derived from a hybrid of a well‐known nickel‐based metal‐organic framework (NiMOF‐74) using thiourea as a sulfur source are reported here. The nanoporous NGO/MOF composite is prepared through a solvothermal process in which Ni(II) metal centers of the MOF structure are chelated with nitrogen and oxygen functional groups of NGO. NGO/Ni₇S₆ exhibits bifunctional activity, capable of catalyzing both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) with excellent stability in alkaline electrolytes, due to its high surface area, high pore volume, and tailored reaction interface enabling the availability of active nickel sites, mass transport, and gas release. Depending on the nitrogen doping level, the properties of graphene oxide can be tuned toward, e.g., enhanced stability of the composite compared to commonly used RuO₂ under OER conditions. Hence, this work opens the door for the development of effective OER/HER electrocatalysts based on hierarchical porous graphene oxide composites with metal chalcogenides, which may replace expensive commercial catalysts such as RuO₂ and IrO₂.     

TiN @ Co5.47N Composite Material Constructed by Atomic Layer Deposition as Reliable Electrocatalyst for Oxygen Evolution Reaction

An efficient and durable oxygen evolution reaction (OER) electrocatalyst consisting of TiN @ Co_5.47N is constructed by the integration of plasma nitriding and a delicate atomic layer deposition (ALD) Co_xN process. Representative results of comprehensive study are: 1) the material is electrocatalytically active in universal medium. The OER overpotentials are 398, 248, and 411 mV in acidic, basic, and neutral electrolyte, respectively, at a current density of 50 mA cm⁻²; 2) the material records an impressive long-term stability of continuous catalysis for 1500 h, during which the overpotential increases by only 1.3%. The synergistically electronic interaction between TiN and ALD Co_5.47N, as well as a protective yet active CoTi layered double hydroxides (CoTi LDH) layer formed simultaneously at the interface/surface of TiN @ Co_5.47N during the electrocatalytic process, is speculated to be responsible for the superior OER performance; 3) the surface Co atoms other than Ti of CoTi LDH, exhibit electrocatalytic activity with dramatically low overpotential based on density functional theory calculations.     

Opportunities and Challenges in Precise Synthesis of Transition Metal Single-Atom Supported by 2D Materials as Catalysts toward Oxygen Reduction Reaction

Transition metal single-atom catalysts (SACs) are currently a hot area of research in the field of electrocatalytic oxygen reduction reaction (ORR). In this review, the recent advances in transition metal single-atom supported by 2D materials as catalysts for ORR with high performance are reported. Due to their large surface area, uniformly exposed lattice plane, and adjustable electronic state, 2D materials are ideal supporting materials for exploring ORR active sites and surface reactions. The rational design principles and synthetic strategies of transition metal SACs supported by 2D materials are systematically introduced while the identification of active sites, their possible catalytic mechanisms as well as the perspectives on the future of transition metal SACs supported by 2D materials for ORR applications are discussed. Finally, according to the current development trend of ORR catalysts, the future opportunities and challenges of transition metal SACs supported by 2D materials are summarized.     

Rational Design of Metal Oxide-Based Heterostructure for Efficient Photocatalytic and Photoelectrochemical Systems

Solar-driven photo-to-chemical conversion is an interesting approach for energy harvesting and storage with high sustainability. To achieve high photo-to-chemical conversion efficiency, it is important to develop cost-effective and stable catalysts with high activity. Metal oxides provide an interesting platform for the development of efficient catalysts owing to their abundance, high stability, and tunable band edges. Their performance highly depends on the rational design of heterostructures with engineered electronic structures, modified charge migration behavior, tailored interfacial properties, and amplified electromagnetic fields. All these enable the achievement of efficient light harvesting, promoted charge separation and transport, and accelerated surface reactions. Herein, a recent study on rationally designed metal oxide heterostructures for enhancing photo-to-chemical energy conversion via photocatalytic and photoelectrochemical systems is reviewed. The approaches to enhance their conversion efficiency are as follows: 1) surface modification via loading of plasmonic metals and other photosensitizers; 2) surface regulation, including morphology, defect, and dopants; 3) interfacial assembly with metal oxides, other metal compounds, and metal-free materials. Moreover, the underlying reaction mechanisms of metal oxide-based heterostructures and how they affect the energy conversion efficiency are discussed. Finally, the challenges and perspectives on the development of metal oxide-based heterostructures and associated photo-to-chemical devices are presented.     

Advances in Manganese‐Based Oxides Cathodic Electrocatalysts for Li–Air Batteries

Li–air batteries, characteristic of superhigh theoretical specific energy density, cost‐efficiency, and environment‐friendly merits, have aroused ever‐increasing attention. Nevertheless, relatively low Coulomb efficiency, severe potential hysteresis, and poor rate capability, which mainly result from sluggish oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) kinetics, as well as pitiful cycle stability caused by parasitic reactions, extremely limit their practical applications. Manganese (Mn)‐based oxides and their composites can exhibit high ORR and OER activities, reduce charge/discharge overpotential, and improve the cycling stability when used as cathodic catalyst materials. Herein, energy storage mechanisms for Li–air batteries are summarized, followed by a systematic overview of the progress of manganese‐based oxides (MnO₂ with different crystal structures, MnO, MnOOH, Mn₂O₃, Mn₃O₄, MnOx, perovskite‐type and spinel‐type manganese oxides, etc.) cathodic materials for Li–air batteries in the recent years. The focus lies on the effects of crystal structure, design strategy, chemical composition, and microscopic physical parameters on ORR and OER activities of various Mn‐based oxides, and even the overall performance of Li–air batteries. Finally, a prospect of the research for Mn‐based oxides cathodic catalysts in the future is made, and some new insights for more reasonable design of Mn‐based oxides electrocatalysts with higher catalytic efficiency are provided.     

Iron Oxyhydroxide: Structure and Applications in Electrocatalytic Oxygen Evolution Reaction

Oxygen evolution reaction (OER) is the anodic half-reaction for crucial energy devices, such as water electrolysis, metal–air battery, and electrochemical CO₂ reduction. Fe-based materials are recognized as one of the most promising electrocatalysts for OER because of its extremely low price and high activity. In particular, iron oxyhydroxide (FeOOH) is not only highly active toward OER, but also widely accepted as the true active species of Fe-based OER electrocatalysts for plenty of Fe-based materials are converted into FeOOH during OER test. Herein, the recent advances of FeOOH-based nano-structure and its application in OER are reviewed. The relationship between FeOOH structure and its catalytic performance, followed by the introduction of current strategies for enhancing the OER activity (i.e., crystalline phase engineering, element doping, and construction of hybrid materials) is mainly focused. Finally, a summary and perspective about the remaining challenges and future opportunities in this area and further the design of Fe-based OER electrocatalysts are provided.     

Cobalt Boron Imidazolate Framework Derived Cobalt Nanoparticles Encapsulated in B/N Codoped Nanocarbon as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

The development of efficient and low‐cost bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable for electrochemical energy conversion. Herein, this study puts forward a new Co decorated N,B‐codoped interconnected graphitic carbon and carbon nanotube materials (Co/NBC) synthesized by direct carbonization of a cobalt‐based boron imidazolate framework. It is demonstrated that the carbonization temperature can tune the surface structure and component of the resultant materials and optimize the electrochemically active surface area to expose more accessible active sites, effectively boosting the electrocatalytic activity. As a result, the optimized Co/NBC shows superior bifunctional catalytic activity and stability toward OER and HER in 1.0 m KOH solution. Furthermore, the catalyst can serve as both the anode and cathode for water splitting to achieve a current density of 10 mA cm^?2 at a cell voltage of 1.68 V. Experimental results and theoretical calculations indicate that the excellent activity of Co/NBC catalyst benefits from the synergistic effect of partial oxidation of metallic cobalt, conductive N,B‐codoped graphitic carbon and carbon nanotube, and the coupled interactions among these components. This work opens a promising avenue toward the exploration of boron imidazolate frameworks as efficient heteroatom‐doped catalysts for electrocatalysis.