Ultrathin nanosheets of cobalt-nickel hydroxides hetero-structure via electrodeposition and precursor adjustment with excellent performance for supercapacitor

A homogeneous better-dispersed ultrathin nanosheets（ca. 5 nm） of cobalt-nickel layered double hydroxides（LDH） supported on nickel foam scaffold was synthesized using controllable electrodeposition approach for high efficiency electrode materials of new supercapacitor. The morphology and electrochemical performances of the samples can be controlled by adjusting the precursor ratio, i.e., Ni（OAc）2/Co（NO3）2 molar ratio in the electrodeposition approach. With the increase of this molar ratio, the electrochemical performances give a volcano trend. When the optimized molar ratio is 0.64/0.36, the hybrid delivered a high specific capacitance of 1587.5 F g-1 at a current density of 0.5 A g-1, with good rate capability（1155 F g-1 was retained even at 10 A g-1） and a robust recycle stability（remaining 91.5% after 1000 cycles at 5 A g-1）. The good performance could be attributed to the enlarged interlayer spacing, ultrathin nanosheets and synergistic effects between Co（OH）2 and Ni（OH）2. Furthermore, an asymmetric supercapacitor with a high energy density of 34.5 Wh kg-1 at 425 W kg-1 and excellent cycling stability of 85.4% after 5000 charge-discharge cycles at 2 A g-1 was fabricated. We believe that this fantabulous new electrode material would have encouraging applications in electrochemical energy storage and a wide readership.

Superhydrophilic nickel hydroxide ultrathin nanosheets enable high-performance asymmetric supercapacitors

Superhydrophilic surfaces have been applied for supercapacitor;however,during energy storage reaction,how the wettability affects the process of electrochemical reaction specifically is still unclear.Herein,we demonstrate superhydrophilic surface for promotion of electrochemical reactions by liquid affinity and further explain the mechanism,where the transition of the wettability state caused by the change in surface free energy is the main reason for the obvious increase in specific capacitance.Through citric acid assistance strategy,an intrinsically hydrophobic Ni(OH)_(2)thick nanosheets(HNHTNs,16 nm)can be transitioned into superhydrophilic Ni(OH)_(2)ultrathin nanosheets(SNHUNs,6.8 nm),where the water contact angle was 0°and the surface free energy increased from 8.6to 65.8 mN·m^(-1),implying superhydrophilicity.Compared with HNHTNs,the specific capacitance of SNHUNs is doubled:from 1230 F·g^(-1)(HNHTNs)to 2350 F·g^(-1)(2A·g^(-1))and,even at 20 A·g^(-1),from 833 F·g^(-1)(HNHTNs)to 1670 F·g^(-1).The asymmetric capacitors assembled by SNHUNs and activated carbon show 52.44 Wh·kg^(-1)at 160W·kg^(-1)and excellent stability with~90%retention after5000 cycles(~80%retention after 9500 cycles).The promotion of electrochemical performances is ascribed to the change of surface wettability caused by surface free energy,which greatly increase affinity of electrode to the surrounding liquid environment to reduce the interface resistance and optimize the electron transport path.

Multi-node CdS hetero-nanowires grown with defect-rich oxygen-doped MoS2 ultrathin nanosheets for efficient visible-light photocatalytic H2 evolution

Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional （1D） multi-node MoS2/CdS hetero-nanowires （NWs） for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets （NSs）, and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.

In situ decomposition of metal-organic frameworks into ultrathin nanosheets for the oxygen evolution reaction

The oxygen evolution reaction （OER） is a pivotal process for water-splitting and many other energy technologies involving oxygen electrodes. Herein, a new synthesis strategy is proposed to prepare OER catalysts based on a simple yet flexible in situ decomposition of Co-based acetate hydroxide metal-organic frameworks （MOFs）. This process allows straightforward fabrication of various 2D hydroxide ultrathin nanosheets （UNSs） with excellent component controllability. The as-obtained Co-based hydroxide UNSs demonstrate superior catalytic activity for the OER due to the exposure of numerous active sites. In particular, the CoNi hydroxide UNSs exhibit low overpotentials （r/） of 324 and 372 mV at current densities of 10 and 100 mA-cm-2, respectively; a large turnover frequency （TOF） of 0.16 s-~ at T/= 380 mV; and a small Tafel slope of 33 mV.dec-~ in an alkaline environment. Importantly, these values are superior to those of the state-of-the- art IrO2 commercial electrocatalyst. This facile strategy enables the exploration of more efficient and economic OER electrocatalysts with various constituents and opens a promising avenue for large-scale fabrication of functional nanocatalysts for use in clean ener~：v technologies.

Ultrathin 2D Metal–Organic Framework Nanosheets In situ Interpenetrated by Functional CNTs for Hybrid Energy Storage Device

The controllable construction of two-dimensional(2D)metal–organic framework(MOF)nanosheets with favorable electrochemical performances is greatly challenging for energy storage.Here,we design an in situ induced growth strategy to construct the ultrathin carboxylated carbon nanotubes(C-CNTs)interpenetrated nickel MOF(Ni-MOF/C-CNTs)nanosheets.The deliberate thickness and specific surface area of novel 2D hybrid nanosheets can be effectively tuned via finely controlling C-CNTs involvement.Due to the unique microstructure,the integrated 2D hybrid nanosheets are endowed with plentiful electroactive sites to promote the electrochemical performances greatly.The prepared Ni-MOF/C-CNTs nanosheets exhibit superior specific capacity of 680 C g^−1 at 1 A g^−1 and good capacity retention.The assembled hybrid device demonstrated the maximum energy density of 44.4 Wh kg^−1 at a power density of 440 W kg^−1.Our novel strategy to construct ultrathin 2D MOF with unique properties can be extended to synthesize various MOF-based functional materials for diverse applications.

Ultrathin Metal Silicate Hydroxide Nanosheets with Moderate Metal-Oxygen Covalency Enables Efficient Oxygen Evolution

Exploring efficient,cost-effective,and durable electrocatalysts for electrochemical oxygen evolution reaction(OER)is pivotal for the large-scale application of water electrolysis.Recent advance has demonstrated that the activity of electrocatalysts exhibits a strong dependence on the surface electronic structure.Herein,a series of ultrathin metal silicate hydroxide nanosheets(UMSHNs)M_(3)Si_(2)O_(5)(OH)_(4)(M=Fe,Co,and Ni)synthesized without surfactant are introduced as highly active OER electrocatalysts.Cobalt silicate hydroxide nanosheets show an optimal OER activity with overpotentials of 287 and 358 m V at 1 and 10 m A cm^(-2),respectively.Combining experimental and theoretical studies,it is found that the OER activity of UMSHNs is dominated by the metal-oxygen covalency(MOC).High OER activity can be achieved by having a moderate MOC as reflected by aσ^(*)-orbital(e_(g))filling near unity and moderate[3d]/[2p]ratio.Moreover,the UMSHNs exhibit favorable chemical stability under oxidation potential.This contribution provides a scientific guidance for further development of active metal silicate hydroxide catalysts.

Bimetallic Au-Pd NPs Embedded in MOF Ultrathin Nanosheets with Tuned Surface Electronic Properties for High-performance Benzyl Alcohol Oxidation

Bimetallic Au-Pd nanoparticles(NPs)with synergistic effect between Au and Pd atom have shown excellent catalytic activity toward benzyl alcohol oxidation.The catalytic activities of metal NPs supported within metal-organic frameworks(MOFs)are affected by the electronic interactions between metal NPs and MOFs.Taking the advantages of ultrathin nanosheets,we confine the highly dispersed Au-Pd NPs within ultrathin nanosheets of MOF-Ni(NMOF-Ni)to fabricate Au_(x)Pd_(y)@NMOF-Ni as catalysts.Under base-free and atmospheric pressure conditions,the as-prepared Au_(x)Pd_(y)@NMOF-Ni catalysts exhibit superior activity and selectivity for benzyl alcohol oxidation.This work highlights the synergistic effects among different components in composite catalysts effectively improving the activity and offers a new way for designing efficient catalysts toward benzyl alcohol oxidation.

Metallic few-layered 1T-VS_(2)nanosheets for enhanced sodium storage

Metallic few-layered 1T phase vanadium disulfide nanosheets have been employed for boosting sodium ion batteries.It can deliver a capacity of 241 mAh∙g^(−1)at 100 mA∙g^(−1)after 200 cycles.Such long-term stability is attributed to the facile ion diffusion and electron transport resulting from the well-designed two-dimensional(2D)electron-electron correlations among V atoms in the 1T phase and optimized in-planar electric transport.Our results highlight the phase engineering into electrode design for energy storage.

Ultrathin curved PdNiRu nanosheets as bifunctional catalysts for oxygen reduction and ethylene glycol oxidation

Pd-based metallic nanosheets with advanced physicochemical properties have been widely prepared and employed in various electrocatalytic reactions.However,few concerns were focused on their multiple performances in different electrocatalysis.Here,highly curved and ultrathin PdNiRu nanosheets(NSs)are developed by facile wet-chemistry strategy and exhibit excellent electrocatalytic performance toward both oxygen reduction reaction(ORR)and ethylene glycol oxidation reaction(EGOR).Owing to the synergistically structural(e.g.,ultrathin,curved,defects/steps-rich)and compositional(ternary alloy)advantages,PdNiRu NSs exhibited enhanced ORR and EGOR specific/mass activities and better stability/durability than control electrocatalysts.The specific activity(5.52 mA·cm^(−2))and mass activity(1.13 A·mg_(Pd)^(−1))of the PdNiRu NSs in ORR are 4.8 and 3.4 times as the ones of commercial Pt/C,respectively.The mass activity of PdNiRu NSs(3.86 A·mg_(Pd)^(−1))in EGOR is 2.6 times as commercial Pd/C(1.51 A·mg_(Pd)^(−1)).This study is helpful for the development of desired electrocatalysts with multi-functional application in practical fuel cells.

Amorphous hybrid tungsten oxide–nickel hydroxide nanosheets used as a highly efficient electrocatalyst for hydrogen evolution reaction

There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyrovsky step).Hybrid amorphous electrocatalysts are highly desirable for efficient hydrogen evolution from water-alkali electrolyzers due to the bifunctionality for the different elementary steps of HER and optimal interactions with water molecules and the reactive hydrogen intermediates(Had).Herein,the synthesis of amorphous hybrid ultrathin(tungsten oxide/nickel hydroxide)hydrate(a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O)nanosheets on nickel foam(NF)for efficient alkaline HER is described.The structural and composition features of a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O are characterized in detailed.The resulting a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O/NF electrocatalyst with the synergistic effect of both hybrid components for the HER elementary steps shows greatly improved the activity and durability for the HER with a low overpotential of-41 and-163 mV at-10 and-500 mA·cm^(-2),respectively,a Tafel slope as low as-72.9 mV·dec^(-1),and long-term stability of continuous electrolysis for at least 150 h accompanying by inappreciable overpotential change in 1 M KOH.In the hybrid a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O,Ni(OH)_(2) and WO_(3) moieties are separately responsible for accelerating dissociative adsorption of water and weakening Had adsorption strength,which is beneficial to the improvement of the alkaline HER activity.

Harnessing Vis-NIR broad spectrum for photocatalytic CO2 reduction over carbon quantum dots-decorated ultrathin Bi2WO6 nanosheets

The photocatalytic reduction of CO2 to energy-rich hydrocarbon fuels is a promising and sustainable method of addressing global warming and the imminent energy crisis concomitantly. However, a vast majority of the existing photocatalysts are only capable of harnessing ultraviolet （UV） or/and visible light （Vis）, whereas the near-infrared （NIR） region still remains unexplored. In this study, carbon quantum dots （CQDs）-decorated ultrathin BizWO6 nanosheets （UBW） were demonstrated to be an efficient photocatalyst for CO2 photoreduction over the Vis-NIR broad spectrum. It is noteworthy that the synthesis procedure of the CQDs/UBW hybrid nanocomposites was highly facile, involving a one-pot hexadecyltrimethylammonium bromide （CTAB）-assisted hydrothermal process. Under visible light irradiation, the optimized 1CQDsAJBW （1 wt.% CQD content） exhibited a remarkable 9.5-fold and 3.1-fold enhancement of CH4 production over pristine Bi2WO6 nanoplatelets （PBW） and bare UBW, respectively. More importantly, the photocatalytic responsiveness of CQDs/UBW was successfully extended to the NIR region, which was achieved without involving any rare earth or noble metals. The realization of NIR-driven CO2 reduction could be attributed to the synergistic effects of （i） the ultrathin nanostructures and highly exposed {001} active facets of UBW, （ii） the excellent spectral coupling of UBW and CQDs, where UBW could be excited by the up-converted photoluminescence of CQDs, and （iii） the electron-withdrawing nature of the CQDs to trap the photogenerated electrons and retard the recombination of charge carriers.

Tunable ultrathin dual-phase P-doped Bi_(2)MoO_(6) nanosheets for advanced lithium and sodium storage

The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a facile strategy of synthesizing ultrathin amorphous/nanocrystal dual-phase P-doped Bi_(2)MoO_(6)(denoted as P-BiMO)nanosheets via a one-step wet-chemical synthesis approach is explored.Quite distinct from conventional two-dimensional(2D)nanosheets,our newly developed ultrathin P-BiMO nanosheets exhibit a unique tunable amorphous/nanocrystalline dual-phase structure with several compelling advantages including fast ion exchange ability and superb volume change buffer capability.The experimental results reveal that our prepared P-BiMO-6 electrode delivers an excellent reversible capacity of 509.6 mA·g^(−1) after continuous 1,500 cycles at the current densities of 1,500 mA·g^(−1) and improved rate performance for LIBs.In the meanwhile,the P-BiMO-6 electrode also shows a reversible capacity of 300.6 mA·g^(−1) after 100 cycles at 50 mA·g^(−1) when being used as the SIBs electrodes.This present work uncovers an effective dual-phase nanosheet structure to improve the performance of batteries,providing an attractive paradigm to develop superior electrode materials.

Novel MoS2 Microspheres Formed by Solid-State Assembly of Ultratliin Nanoslieets

The MoS2 microspheres with high specific surface area assembled by ultrathin nanosheets have been successfully synthesized by a facile and environmentally friendly reaction in a closed reactor at moderate temperatures.The solid-state assembly was realized by a simple calcination process,and the annealing temperature played a key role in the formation of the final microspheres.The influences of reaction temperature were carefully investigated.A possible formation mechanism about the solid-state assembly was proposed based on the experimental results.

Ultrathin ZnIn_(2)S_(4)Nanosheets-Supported Metallic Ni_(3)FeN for Photocatalytic Coupled Selective Alcohol Oxidation and H_(2)Evolution

Photocatalytic anaerobic organic oxidation coupled with H_(2)evolution represents an advanced solar energy utilization strategy for the coproduction of clean fuel and fine chemicals.To achieve a high conversion efficiency,the smart design of efficient catalysts by the right combination of semiconductor light harvesters and cocatalyst is highly required.Herein,we report a composite photocatalyst composed of noble metal-free transition metal nitride Ni_(3)FeN decorated on 2D ultrathin ZnIn_(2)S_(4)(ZIS)nanosheets for selective oxidation of aromatic alcohols to aldehydes pairing with H_(2)production.In the composite,ultrathin ZIS serves as a light harvester that greatly shortens the diffusion length of photogenerated charges,while the metallic nitride Ni_(3)FeN acts as an advanced cocatalyst which not only captures the photoelectrons generated from the ultrathin ZIS to promote the charge separation,but also provides active sites to lower the overpotential and accelerate the H_(2)reduction.The best photocatalytic performance is found on ZIS/1.5%M-Ni_(3)FeN,which shows a H_(2)generation rate of 2427.9μmol g^(^(-1))h^(-1)and a benzaldehyde(BAD)production rate of 2460μmol g^(-1)h^(-1),about 7.8-fold as high as that of bare ZIS.This work is anticipated to endorse the exploration of transition metal nitrides as high-performance cocatalysts to promote the coupled photocatalytic organic transformation and H_(2)production.

Ultrathin Metal-Organic Framework Nanosheets-Derived Yolk-Shell Ni_(0.85)Se@NC with Rich Se-Vacancies for Enhanced Water Electrolysis

We present a controlled fabrication of selective ultrathin metal-organic framework(MOF)nanosheets as preassembling platforms,yolk-shell structured with a few-layered N-doped carbon(NC)shell-encapsulated Ni_(0.85)Se core(denoted as Ni_(0.85)Se@NC)via an oriented phase modulation(OPM)strategy.The ultrathin nature of the MOF nanosheets gave rise to the modification of structure at the electronic level with abundant Se-vacancies and effective electronic coupling via an Ni-N_(x) coordination at the interface between the Ni0.85Se core and NC shell.The Ni0.85Se@NC obtained exhibited low overpotentials for both oxygen evolution reaction(OER;300 mV)and hydrogen evolution reaction(HER;157 mV)at 10 mA·cm^(−2) under an alkaline condition,outperforming their corresponding bulk MOF-derived counterparts.By exploiting Ni_(0.85)Se@NC as anode and cathode catalysts,a low cell voltage of 1.61 V was achieved by performing alkaline water electrolysis.Remarkably,it also reached a high activity in natural seawater(pH=7.98)and simulated seawater(pH=7.86)electrolytes,even surpassing integrated Pt/C-RuO_(2)/CC electrodes.Density functional theory(DFT)studies illustrated that abundant Se-vacancies effectively regulated the electronic structure of Ni_(0.85)Se@NC by accelerating electron transfer from Ni to N atoms at the interface,and thus,enabling the Ni_(0.85)Se@NC to attain a near-optimal electronic configuration that stimulated ideal adsorption-free energy toward key reaction intermediates.

Electrosynthesis of Co3O4 and Co（OH）2 ultrathin nanosheet arrays for efficient electrocatalytic water splitting in alkaline and neutral media

The dimensional confinement endows ultrathin nanosheets with unique physical and chemical properties, which have been widely studied for the purpose of developing active electrocatalysts for water splitting. Ultrathin nanosheets are generally synthesized by chemical vapor deposition, exfoliation, or surfactant- assisted synthesis, which either require special equipment and reaction conditions, or is limited by the low yields and the difficulty in controlling the lateral size and structure of the nanosheets. In addition, achieving a high loading of ultrathin nanosheets on the electrodes without compromising their catalytic activity still remains a challenge. Herein, we report a simple electrodeposition method for preparing C0304 and Co（OH）2 ultrathin nanosheet arrays （UNA） without using templates or surfactants. The obtained arrays exhibit high activity for oxygen and hydrogen evolution reactions, in both alkaline and neutral media. The electrolyzer based on Co304 and Co（OH）2 UNA shows superior activity and stability than that based on IrO2 and Pt/C, which demonstrates the potential of the present electrodeposition method for developing active and stable electrocatalysts for water splitting.

Self-transforming ultrathin α-Co(OH)2 nanosheet arrays from metal-organic framework modified graphene oxide with sandwichlike structure for efficient electrocatalytic oxygen evolution

Developing efficient and low-cost electrocatalysts for oxygen evolution reaction(OER)with high electrochemical activity and durability for diverse renewable and sustainable energy technologies remains challenging.Herein,an ultrasonic-assisted and coordination modulation strategy is developed to construct sandwich-like metal-organic framework(MOF)derived hydroxide nanosheet(NS)arrays/graphene oxide(GO)composite via one-step self-transformation route.Inducing from unsteady state,the dodecahedral ZIF-67 with Co^2+in tetrahedral coordination auto-converts into defect-rich ultrathin layered hydroxides with the interlayered ion NO3-.The self-transforming a-Co(OH)2/GO nanosheet arrays from ZIF-67(Co(OH)2-GNS)change the coordination mode of Co^2+and bring about the exposure of more metal active sites,thereby enhancing the spatial utilization ratio within the framework.As monometal-based electrocatalyst,the optimized Co(OH)2-GNS exhibits remarkable OER catalytic performance evidenced by a low overpotential of 259 mV to achieve a current density of 10 mA·cm-2 in alkaline medium,even exceeding commercial RuO2.During the oxygen evolution process,electron migration can be accelerated by the interfacial/in-plane charge polarization and local electric field,corroborated by the off-axis electron holography.Density functional theory(DFT)calculations further studied the collaboration between ultrathin Co(OH)2 NS and GO,which leads to lower energy barriers of intermediate products and greatly promotes electrocatalytic property.

Z-scheme photocatalyst based on porphyrin derivative decorated few-layer BiVO4 nanosheets for efficient visible-light-driven overall water splitting

It is highly desirable to simulate natural photosynthesis by using sunlight to drive the overall water splitting without using external bias and sacrificial agent.Herein,few-layer monoclinic BiVO4 nanosheets(BVNS)with a thickness of(∼)4.3 nm,exposed(010)facets and abundant oxygen vacancies are fabricated using graphene oxide dots as templating reagent.After decorating with asymmetric chromium porphyrin derivative bearing one benzoic acid and three phenyls as meso-position substituents(chromium-5-(4-carboxyphenyl)-10,15,20-triphenylporphrin,CrmTPP)and PtOx cocatalyst,the obtained two-dimensional(2D)hybrid nanocomposite(BVNS/CrmTPP/Pt)with an optimal component ratio delivers a robust overall water splitting performance with a relatively high apparent quantum yield(8.67%)at 400 nm monochromatic light.The ultrathin structure and widely distributed oxygen vacancies on the exposed(010)facets of BVNS not only endow strong and intimate contact with the decorated CrmTPP molecules to promote a two-step excitation Z-scheme charge transfer mechanism for preserving the high redox ability of the photogenerated charge carriers,but also alleviate their recombination,and thus causing the robust overall water splitting performance of the 2D hybrid nanocomposites.The present results provide a novel strategy to construct highly efficient artificial photosynthetic system for overall water splitting.

Ru(bpy)_(3)^(2+)-sensitized{001}facets LiCoO_(2) nanosheets catalyzed CO_(2) reduction reaction with 100% carbonaceous products

Photosensitized heterogeneous CO_(2) reduction(PHCR)has emerged as a promising means to convert CO_(2) into valuable chemicals,however,challenged by the relatively low carbonaceous product selectivity caused by the competing hydrogen evolution reaction(HER).Here,we report a PHCR system that couples Ru(bpy)32+photosensitizer with{001}faceted LiCoO_(2) nanosheets photocatalyst to simultaneously yield 21.2 and 722μmol·g^(-1)·h^(-1) of CO,and 4.42 and 108μmol·g^(-1)·h^(-1) of CH4 under the visible light and the simulated sunlight irradiations,respectively,with completely suppressed HER.The experimental and theoretical studies reveal that the favored CO_(2) adsorption on the exposed Li sites on{001}faceted LiCoO_(2) surface is responsible for the completely suppressed HER.

Interface construction of NiCo LDH/NiCoS based on the 2D ultrathin nanosheet towards oxygen evolution reaction

Carbon-free hydrogen as a promising clean energy source can be produced with electrocatalysts via water electrolysis.Oxygen evolution reaction(OER)as anodic reaction determines the overall efficiency of water electrolysis due to sluggish OER kinetics.Thus,it’s much desirable to explore the efficient and earth-abundant transition-metal-based OER electrocatalysts with high current density and superior stability for industrial alkaline electrolyzers.Herein,we demonstrate a significant enhancement of OER kinetics with the hybrid electrocatalyst arrays in alkaline via judiciously combining earth-abundant and ultrathin NiCo-based layered double hydroxide(NiCo LDH)nanosheets with nickel cobalt sulfides(NiCoS)with a facile metal-organic framework(MOF)-template-involved surface sulfidation process.The obtained NiCo LDH/NiCoS hybrid arrays exhibits an extremely low OER overpotential of 308 mV at 100 mA·cm^(−2),378 mV at 200 mA·cm^(−2)and 472 mV at 400 mA·cm^(−2)in 1 M KOH solution,respectively.A much low Tafel slope of 48 mV·dec^(−1)can be achieved.Meanwhile,with the current density from 50 to 250 mA·cm^(−2),the NiCo-LDH/NiCoS hybrid arrays can run for 25 h without any degradation.Our results demonstrate that the construction of hybrid arrays with abundant interfaces of NiCo LDH/NiCoS can facilitate OER kinetics via possible modulation of binding energy of O-containing intermediates in alkaline media.The present work would pave the way for the development of lowcost and efficient OER catalysts and industrial application of water alkaline electrolyzers.