Fabrication of Polyoxometalate Anchored Zinc Cobalt Sulfide Nanowires as a Remarkable Bifunctional Electrocatalyst for Overall Water Splitting

The advancement of a naturally rich and effective bifunctional substance for hydrogen and oxygen evolution reaction is crucial to enhance hydrogen fuel production efficiency via the electrolysis process. Herein, facile and scalable hydrothermal synthesis of bifunctional electrocatalyst of polyoxometalate anchored zinc cobalt sulfide nanowire on Ni-foam (NF) for overall water splitting is reported for the first time. The electrochemical analysis of POM@ZnCoS/NF displays significantly low HER and OER overpotentials of 170/337 and 200/300 mV to attain a current density of 10/40 and 20/50 mA cm⁻², respectively, demonstrating the notable performance of POM@ZnCoS/NF toward H₂ and O₂ evolution reaction in alkaline medium. Additionally, the electrolyzer consisting of the POM@ZnCoS/NF anode and cathode shows an appealing potential of 1.56 V to deliver 10 mA cm⁻² current density for overall water splitting. The high electrocatalytic activity of the POM@ZnCoS/NF is attributed to modulation of the electronic and chemical properties, increment of the electroactive sites and electrochemically active surface area of the zinc cobalt sulfide nanowires due to the anchorage of polyoxometalate nanoparticles. These results demonstrate the advantage of the polyoxometalate incorporation strategy for the design of cost-effective and highly competent bifunctional catalysts for complete water splitting.     

Atomic‐Level Coupled Interfaces and Lattice Distortion on CuS/NiS2 Nanocrystals Boost Oxygen Catalysis for Flexible Zn‐Air Batteries

The exploration of highly efficient nonprecious metal bifunctional electrocatalysts to boost oxygen evolution reaction and oxygen reduction reaction is critical for development of high energy density metal‐air batteries. Herein, a class of CuS/NiS₂ interface nanocrystals (INs) catalysts with atomic‐level coupled nanointerface, subtle lattice distortion, and plentiful vacancy defects is reported. The results from temperature‐dependent in situ synchrotron‐based X‐ray absorption fine spectroscopy and electron spin resonance spectroscopy demonstrate that the lattice distortion of 14.7% in CuS/NiS₂ caused by the strong Jahn–Teller effect of Cu, the strong atomic‐level coupled interface of CuS and NiS₂ domains, and distinct vacancy defects can provide numerous effective active sites for their excellent bifunctional performance. A liquid Zn‐air battery with the CuS/NiS₂ INs as air electrode displays a large peak power density (172.4 mW cm^?2), a high specific capacity (775 mAh g_Zn^?1), and long cycle life (up to 83 h), making the CuS/NiS₂ INs among the best bifunctional catalysts for Zn‐air battery. More remarkably, the flexible CuS/NiS₂ INs‐based solid‐state Zn‐air batteries can power the LED after twisting, making them be promising in portable and wearable electronic devices.     

Ru–Ru2PΦNPC and NPC@RuO2 Synthesized via Environment‐Friendly and Solid‐Phase Phosphating Process by Saccharomycetes as N/P Sources and Carbon Template for Overall Water Splitting in Acid Electrolyte

Although numerous ruthenium‐based phosphates possess high catalytic activities for hydrogen evolution reaction (HER), most of them rely on dangerous and toxic synthesis routes. Biological slices confirm that Ru ions can penetrate the cell walls of saccharomycete, which facilitates the adsorption of Ru ions. Herein, based on a green synthesis process by saccharomycete cells as the carbon template and nitrogen/phosphorus (N/P) sources, novel Janus‐like ruthenium–ruthenium phosphide nanoparticles embedded into a N/P dual‐doped carbon matrix (Ru–Ru₂PΦNPC) electrocatalyst for HER are synthesized. Electrochemical tests reveal that Ru–Ru₂PΦNPC displays remarkable performance with a low overpotential of 42 mV at 10 mA cm^?2 and demonstrates superior stability at a high current density in 0.5 m H₂SO₄. Furthermore, ruthenium oxide nanoparticles coated N/P dual‐doped carbon (NPC@RuO₂) are also synthesized with a yolk–shell structure using saccharomycete cells as the core template and RuO₂ as a shell to isolate saccharomycete cells from the oxidation reaction during calcination in air. The NPC@RuO₂ as oxygen evolution reaction electrocatalyst possesses a low overpotential of 220 mV at 10 mA cm^?2. Finally, the Ru–Ru₂PΦNPC is integrated as a cathode and NPC@RuO₂ is integrated as an anode to construct a two‐electrode electrolyzer to enable an excellent performance for overall water splitting with a cell voltage of 1.50 V at 10 mA cm^?2 in 0.5 m H₂SO₄.     

N‐, O‐, and S‐Tridoped Carbon‐Encapsulated Co9S8 Nanomaterials: Efficient Bifunctional Electrocatalysts for Overall Water Splitting

The development of highly active and stable earth‐abundant catalysts to reduce or eliminate the reliance on noble‐metal based ones in green and sustainable (electro)chemical processes is nowadays of great interest. Here, N‐, O‐, and S‐tridoped carbon‐encapsulated Co₉S₈ (Co₉S₈@NOSC) nanomaterials are synthesized via simple pyrolysis of S‐ and Co(II)‐containing polypyrrole solid precursors, and the materials are proven to serve as noble metal‐free bifunctional electrocatalysts for water splitting in alkaline medium. The nanomaterials exhibit remarkable catalytic performances for oxygen evolution reaction in basic electrolyte, with small overpotentials, high anodic current densities, low Tafel slopes as well as very high (nearly 100%) Faradic efficiencies. Moreover, the materials are found to efficiently electrocatalyze hydrogen evolution reaction in acidic as well as basic solutions, showing high activity in both cases and maintaining good stability in alkaline medium. A two‐electrode electrolyzer assembled using the material synthesized at 900 °C (Co₉S₈@NOSC‐900) as an electrocatalyst at both electrodes gives current densities of 10 and 20 mA cm^?2 at potentials of 1.60 and 1.74 V, respectively. The excellent electrocatalytic activity exhibited by the materials is proposed to be mainly due to the synergistic effects between the Co₉S₈ nanoparticles cores and the heteroatom‐doped carbon shells in the materials.     

Porous Pd/NiFeOx Nanosheets Enhance the pH-Universal Overall Water Splitting

Modulating the morphology and chemical composition is an efficient strategy to enhance the catalytic activity for water splitting, since it is still a great challenge to develop a bifunctional catalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) over a wide pH range. Herein, Pd/NiFeO_x nanosheets are synthesized with tightly arranged petal nanosheets and uniform mesoporous structure on nickel foam (NF). The porous 2D structure yields a larger surface area and exposes more active sites, facilitating water splitting at all pH values. The overpotential of Pd/NiFeO_x nanosheets for OER is only 180, 169, and 310 mV in 1 m KOH, 0.5 m H₂SO₄, and 1 m phosphate-buffered saline (PBS) conditions at 10 mA cm⁻² current density, as well as excellent HER activity with ultralow overpotential in a wide pH range. When using porous Pd/NiFeO_x nanosheets as bifunctional catalysts for water splitting, it just required a cell voltage of 1.57 V to reach a current density of 20 mA cm⁻² with nearly 100% faradic efficiency in alkaline conditions, which is much lower than that of benchmark Pt/CǁRuO₂ (1.76 V) couples, along with the improving stability benefiting from the good corrosion resistance of the inner NiFeO_x nanosheets.     

Efficient and Stable Bifunctional Electrocatalysts Ni/NixMy (M = P,S) for Overall Water Splitting

Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni₈P₃ and Ni/Ni₉S₈ electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni₈P₃ as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm^?2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO₂ and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels.     

One‐Step Synthesis of CoS‐Doped β‐Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

Developing efficient and economical electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction with readily available metals is one of the main challenges for large scale hydrogen/oxygen production. This study reports one step synthesis of cobalt and molybdenum hybrid materials for high performance overall water splitting. The binder‐free CoS‐doped β‐Co(OH)₂@amorphous MoS_2+x is coated on nickel foam (NF) to form 3D networked nanoplates that have large surface area and high durability for electrochemical reactions. The catalytic activity of electrocatalyst for hydrogen evolution is mainly attributed to the unsaturated sulfur site of amorphous MoS_2+x. Meanwhile, the CoS‐doped β‐Co(OH)₂ plays the major role in oxygen evolution. CoS‐doped β‐Co(OH)₂ and aMoS_2+x are strongly bound to each other due to CoS_x bridging. This CoS? Co(OH)₂@aMoS_2+x/NF hybrid exhibits excellent catalytic activity and stability for overall water splitting. For over 100 000 s the cell voltage required to achieve the current density of 10 mA cm^–2 is only 1.58 V, which is remarkably low among the commercially available electrocatalysts. The findings open up an easy and inexpensive method of large scale fabrication of bifunctional electrocatalysts for overall water splitting.     

Heterogeneous Bimetallic Mo-NiPx/NiSy as a Highly Efficient Electrocatalyst for Robust Overall Water Splitting

Highly efficient electrocatalysts composed of earth-abundant elements are desired for water-splitting to produce clean and renewable chemical fuel. Herein, a heteroatomic-doped multi-phase Mo-doped nickel phosphide/nickel sulfide (Mo-NiP_x/NiS_y) nanowire electrocatalyst is designed by a successive phosphorization and sulfuration method for boosting overall water splitting (both oxygen and hydrogen evolution reactions (HER)) in alkaline solution. As expected, the Mo-NiP_x/NiS_y electrode possesses low overpotentials both at low and high current densities in HER, while the Mo-NiP_x/NiS_y heterostructure exhibits high active performance with ultra-low overpotentials of 137, 182, and 250 mV at the current density of 10, 100, and 400 mA cm⁻² in 1 m KOH solution, respectively, in oxygen evolution reaction. In particular, the as-prepared Mo-NiP_x/NiS_y electrodes exhibit remarkable full water splitting performance at both low and high current densities of 10, 100, and 400 mA cm⁻² with 1.42, 1.70, and 2.36 V, respectively, which is comparable to commercial electrolysis.     

Bifunctional Heterostructure Assembly of NiFe LDH Nanosheets on NiCoP Nanowires for Highly Efficient and Stable Overall Water Splitting

3D hierarchical heterostructure NiFe LDH@NiCoP/NF electrodes are prepared successfully on nickel foam with special interface engineering and synergistic effects. This research finds that the as‐prepared NiFe LDH@NiCoP/NF electrodes have a more sophisticated inner structure and intensive interface than a simple physical mixture. The NiFe LDH@NiCoP/NF electrodes require an overpotential as low as 120 and 220 mV to deliver 10 mA cm^?2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, respectively. Tafel and electrochemical impedance spectroscopy further reveal a favorable kinetic during electrolysis. Specifically, the NiFe LDH@NiCoP/NF electrodes are simultaneously used as cathode and anode for overall water splitting, which requires a cell voltage of 1.57 V at 10 mA cm^?2. Furthermore, the synergistic effect of the heterostructure improves the structural stability and promotes the generation of active phases during HER and OER, resulting in excellent stability over 100 h of continuous operation. Moreover, the strategy and interface engineering of the introduced heterostructure can also be used to prepare other bifunctional and cost‐efficient electrocatalysts for various applications.     

Mechanistic Insights on Ternary Ni2−xCoxP for Hydrogen Evolution and Their Hybrids with Graphene as Highly Efficient and Robust Catalysts for Overall Water Splitting

Searching the high‐efficient, stable, and earth‐abundant electrocatalysts to replace the precious noble metals holds the promise for practical utilizations of hydrogen and oxygen evolution reactions (HER and OER). Here, a series of highly active and robust Co‐doped nickel phosphides (Ni_2?xCo_xP) catalysts and their hybrids with reduced graphene oxide (rGO) are developed as bifunctional catalysts for both HER and OER. The Co‐doping in Ni₂P and their hybridization with rGO effectively regulate the catalytic activity of the surface active sites, accelerate the charge transfer, and boost their superior catalytic activity. Density functional theory calculations show that the Co‐doped catalysts deliver the moderate trapping of atomic hydrogen and facile desorption of the generated H₂ due to the H‐poisoned surface active sites of Ni_2?xCo_xP under the real catalytic process. Electrochemical measurements reveal the high HER efficiency and durability of the NiCoP/rGO hybrids in electrolytes with pH 0–14. Coupled with the remarkable and robust OER activity of the NiCoP/rGO hybrids, the practical utilization of the NiCoP/rGO‖NiCoP/rGO for overall water splitting yields a catalytic current density of 10 mA cm^?2 at 1.59 V over 75 h without an obvious degradation and Faradic efficiency of ≈100% in a two‐electrode configuration and 1.0 m KOH.     

Mo-/Co-N-C Hybrid Nanosheets Oriented on Hierarchical Nanoporous Cu as Versatile Electrocatalysts for Efficient Water Splitting

Designing robust and cost-effective electrocatalysts based on Earth-abundant elements is crucial for large-scale hydrogen production through electrochemical water splitting. Here, nitrogen-doped carbon engrafted Mo₂N/CoN hybrid nanosheets that are seamlessly oriented on hierarchical nanoporous Cu scaffold (Mo-/Co-N-C/Cu), as highly efficient electrocatalysts for alkaline hydrogen evolution reaction are reported. The constituent heterostructured Mo₂N/CoN nanosheets work as bifunctional electroactive sites for both water dissociation and adsorption/desorption of hydrogen intermediates while the nitrogen-doped carbon bridges electron transfers between electroactive sites and interconnective Cu current collectors by making use of Mo-/Co-N-C bonds and intimate C/Cu contacts at interfaces. As a consequence of unique architecture having electroactive sites to be sufficiently accessible, self-supported nanoporous Mo-/Co-N-C/Cu hybrid electrodes exhibit outstanding electrocatalysis in 1 m KOH, with a negligible onset overpotential and a low Tafel slope of 47 mV dec⁻¹. They only take overpotential of as low as 230 mV to reach current density of 1000 mA cm⁻². When coupled with their electro-oxidized derivatives that mediate efficiently the oxygen evolution reaction, the alkaline water electrolyzer can achieve ≈100 mA cm⁻² at 1.622 V in 1 m KOH electrolyte, ≈0.343 V lower than the device constructed with commercially available Pt/C and Ir/C nanocatalysts immobilized on nanoporous Cu electrodes.     

Corrosion Engineering on Iron Foam toward Efficiently Electrocatalytic Overall Water Splitting Powered by Sustainable Energy

Exploiting highly effective and low-cost electrocatalysts for the hydrogen evolution reaction (HER) is a pressing challenge for the development of sustainable hydrogen energy. In this work, a facile and industrially compatible one-pot corrosion strategy for the rapid synthesis of amorphous RuO₂-decorated FeOOH nanosheets on iron foam (FF Na Ru) within 1 h is reported. Corrosion is a common and inevitable phenomenon that occurs on metal surfaces without electricity input, high temperature, and tedious synthetic procedures. The FF Na Ru electrode is superhydrophilic and aerophobic, which guarantees intimate contact with the electrolyte and accelerates the instantaneous escape of produced gas bubbles during the electrocatalytic process. Moreover, the strong electronic interactions between RuO₂ and FeOOH promote the electrocatalytic process via dramatically improving the electrochemical interfacial properties. Thus, the FF Na Ru electrocatalyst presents excellent catalytic activity towards the HER (30 mV at 10 mA cm^–2) and overall water-splitting (230 mV at 10 mA cm^–2) in 1 M KOH. The overall water-splitting could be simply powered by sustainable and intermittent sunlight, wind, and thermal energies motivated Stirling engine. Density functional theory calculations confirm that coupling effects between RuO₂ and FeOOH are also responsible for promoting the electrocatalytic HER performance.     

Ar/H2/O2-Controlled Growth Thermodynamics and Kinetics to Create Zero-, One-, and Two-Dimensional Ruthenium Nanocrystals towards Acidic Overall Water Splitting

A gas controlled formation strategy is developed to synthesize free-standing 0D Ru nanoparticles, 1D Ru nanowires, and 2D Ru nanosheets through in-situ regulated growth thermodynamics and kinetics with typical inert, reductive, and oxidative gases (Ar/H₂/O₂). The growth process of these Ru nanoparticles, nanowires, and nanosheets follow non-directional growth, shape-directed nanoparticle attachment, and directional growth mechanisms, respectively. Kinetics studies approve that H₂ accelerates the reduction rate of the Ru precursor, while O₂ depresses the reduction. The calculation results of the Gibbs surface free energy under different gas coverage further show that small molecules’ gas can effectively regulate the surface state and growth rate. These Ru nanocrystals exhibit excellent acidic water splitting performance. This work has systematically studied the influence of the small molecule gas on the formation process of the Ru nanocrystals, and provides an effective idea for the development and research of high-performance nanomaterials in the future.     

Bifunctional Nickel Phosphide Nanocatalysts Supported on Carbon Fiber Paper for Highly Efficient and Stable Overall Water Splitting

Self‐supported electrodes comprising carbon fiber paper (CP) integrated with bifunctional nickel phosphide (Ni‐P) electrocatalysts are fabricated by electrodeposition of Ni on functionalized CP, followed by a convenient one‐step phosphorization treatment in phosphorus vapor at 500 °C. The as‐fabricated CP@Ni‐P electrode exhibits excellent electrocatalytic performance toward hydrogen evolution in both acidic and alkaline solutions, with only small overpotentials of 162 and 250 mV, respectively, attaining a cathodic current density of 100 mA cm^?2. Furthermore, the CP@Ni‐P electrode also exhibits superior catalytic performance toward oxygen evolution reaction (OER). An exceptionally high OER current of 50.4 mA cm^?2 is achieved at an overpotential of 0.3 V in 1.0 m KOH. The electrode can sustain 10 mA cm^?2 for 180 h with only negligible degradation, showing outstanding durability. Detailed microstructural and compositional studies reveal that upon OER in alkaline solution the surface Ni‐P is transformed to NiO covered with a thin Ni(OH)_x layer, forming a Ni‐P/NiO/Ni(OH)_x heterojunction, which presumably enhances the electrocatalytic performance for OER. Given the well‐defined bifunctionality, a full alkaline electrolyzer is constructed using two identical CP@Ni‐P electrodes as cathode and anode, respectively, which can realize overall water splitting with efficiency as high as 91.0% at 10 mA cm^?2 for 100 h.     

High‐Performance Overall CO2 Splitting on Hierarchical Structured Cobalt Disulfide with Partially Removed Sulfur Edges

The ability to develop bifunctional electrocatalysts for concurrent CO₂ reduction reaction (CO₂RR) and oxygen evolution reaction (OER) is the key to the practical application of CO₂ splitting to produce CO. However, this remains a grand challenge. Herein, a robust strategy to rationally craft hierarchical structured bifunctional electrocatalysts composed of 3D CoS₂ nanocages interconnected on 2D CoS₂ nanosheet arrays (denoted hierarchical CoS₂ nanocages) for high‐performance CO₂ splitting is developed. The subsequent calcination removes the partial S edges of CoS₂, thereby strongly suppressing the hydrogen evolution reaction (HER) of CoS₂. By combining theoretic and experimental results, for the first time, it is discovered that the plane S of CoS₂, instead of S edges, are highly active for CO₂RR but inactive for HER, rendering the plane S as ideal active sites for CO₂RR. Intriguingly, the composition tuning via calcination and the presence of a hierarchical architecture confer hierarchical CoS₂ nanocages respective outstanding CO₂RR and OER performance. Notably, the hierarchical CoS₂ nanocages can be exploited as bifunctional electrocatalysts for overall CO₂ splitting to yield the current density of 1 mA cm^?2 at a small cell voltage of 1.92 V, much lower than the widely reported values (>2.5 V).     

A Self‐Standing High‐Performance Hydrogen Evolution Electrode with Nanostructured NiCo2O4/CuS Heterostructures

An efficient self‐standing 3D hydrogen evolution cathode has been developed by coating nickel cobaltite (NiCo₂O₄)/CuS nanowire heterostructures on a carbon fiber paper (CFP). The obtained CFP/NiCo₂O₄/CuS electrode shows exceptional hydrogen evolution reaction (HER) performance and excellent durability in acidic conditions. Remarkably, as an integrated 3D hydrogen‐evolving cathode operating in acidic electrolytes, CFP/NiCo₂O₄/CuS maintains its activity more than 50 h and exhibits an onset overpotential of 31.1 mV, an exchange current density of 0.246 mA cm^?2, and a Tafel slope of 41 mV dec^?1. Compared to other non‐Pt electrocatalysts reported to date, CFP/NiCo₂O₄/CuS exhibits the highest HER activity and can be used in HER to produce H₂ with nearly quantitative faradaic yield in acidic aqueous media with stable activity. Furthermore, by using CFP/NiCo₂O₄/CuS as a self‐standing electrode in a water electrolyzer, a current density of 18 mA cm^?2 can be achieved at a voltage of 1.5 V which can be driven by a single‐cell battery. This strategy provides an effective, durable, and non‐Pt electrode for water splitting and hydrogen generation.     

N‐Doped CsTaWO6 as a New Photocatalyst for Hydrogen Production from Water Splitting Under Solar Irradiation

Photocatalysts for efficient solar hydrogen production are highly sought after. Here a new type of nitrogen‐doped tantalum tungstenate (CsTaWO₆) material, which demonstrates excellent visible light absorption and improved photocatalytic activity, is demonstrated. X‐ray diffraction (XRD) patterns reveal that the defect pyrochlore‐type structure of CsTaWO₆ remained intact upon nitrogen doping. UV‐vis spectra indicate that nitrogen doping in the compound results in a red‐shift of the absorption edge from 358 nm to 580 nm, thus offering significantly increased visible light absorption. X‐ray photoelectron spectroscopy (XPS) further indicates that [Ta/W]–N bonds were formed by inducing nitrogen to replace a small amount of oxygen in the material, resulting in a compound of CsTaWO_6‐xN_x. The explanation of the experimental results is supported by density functional theory calculations. The density of states (DOS) and the projected DOS after substitutional doping of nitrogen in CsTaWO₆ indicated that N‐doping reduces the bandgap significantly from 3.8 to 2.3 eV due to N 2p and O 2p orbital mixing. The role of the new N 2p states is also investigated by studying the production of the ?OH radicals in the visible light region (>420 nm). In CsTaWO_6‐xN_x, the N 2p orbitals are the main contributors to the top of the valence band, causing bandgap narrowing while the bottom of conduction band, due to Ta 4d orbitals, remains almost unchanged. Compared with its undoped counterpart, nitrogen‐doped CsTaWO_6‐xN_x exhibits a nearly 100% increase in solar hydrogen production efficiency.     

Bamboo‐Like Hollow Tubes with MoS2/N‐Doped‐C Interfaces Boost Potassium‐Ion Storage

Potassium‐ion batteries (KIBs) are new‐concept of low‐cost secondary batteries, but the sluggish kinetics and huge volume expansion during cycling, both rooted in the size of large K ions, lead to poor electrochemical behavior. Here, a bamboo‐like MoS₂/N‐doped‐C hollow tubes are presented with an expanded interlayer distance of 10 Å as a high‐capacity and stable anode material for KIBs. The bamboo‐like structure provides gaps along axial direction in addition to inner cylinder hollow space to mitigate the strains in both radial and vertical directions that ultimately leads to a high structural integrity for stable long‐term cycling. Apart from being a constituent of the interstratified structure the N‐doped‐C layers weave a cage to hold the potassiation products (polysulfide and the Mo nanoparticles) together, thereby effectively hindering the continuing growth of solid electrolyte interphase in the interior of particles. The density functional theory calculations prove that the MoS₂/N‐doped‐C atomic interface can provide an additional attraction toward potassium ion. As a result, it delivers a high capacity at a low current density (330 mAh g^?1 at 50 mA g^?1 after 50 cycles) and a high‐capacity retention at a high current density (151 mAh g^?1 at 500 mA g^?1 after 1000 cycles).     

Regulating the Electronic Structure of CoP Nanosheets by O Incorporation for High‐Efficiency Electrochemical Overall Water Splitting

The exploration of earth‐abundant and high‐efficiency bifunctional electrocatalysts for overall water splitting is of vital importance for the future of the hydrogen economy. Regulation of electronic structure through heteroatom doping represents one of the most powerful strategies to boost the electrocatalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, a rational design of O‐incorporated CoP (denoted as O‐CoP) nanosheets, which synergistically integrate the favorable thermodynamics through modification of electronic structures with accelerated kinetics through nanostructuring, is reported. Experimental results and density functional theory simulations manifest that the appropriate O incorporation into CoP can dramatically modulate the electronic structure of CoP and alter the adsorption free energies of reaction intermediates, thus promoting the HER and OER activities. Specifically, the optimized O‐CoP nanosheets exhibit efficient bifunctional performance in alkaline electrolyte, requiring overpotentials of 98 and 310 mV to deliver a current density of 10 mA cm^?2 for HER and OER, respectively. When served as bifunctional electrocatalysts for overall water splitting, a low cell voltage of 1.60 V is needed for achieving a current density of 10 mA cm^?2. This proposed anion‐doping strategy will bring new inspiration to boost the electrocatalytic performance of transition metal–based electrocatalysts for energy conversion applications.