Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped Co...Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.展开更多
The most energy-inefficient step in the oxygen evolution reaction(OER), which involves a complicated four-electron transfer process, limits the efficiency of the electrochemical water splitting. Here, well-defined Ni/...The most energy-inefficient step in the oxygen evolution reaction(OER), which involves a complicated four-electron transfer process, limits the efficiency of the electrochemical water splitting. Here, well-defined Ni/Co3O4 nanoparticles coupled with N-doped carbon hybrids(Ni/Co3O4@NC) were synthesized via a facile impregnation-calcination method as efficient electrocatalysts for OER in alkaline media. Notably, the impregnation of the polymer with Ni and Co ions in the first step ensured the homogeneous distribution of metals, thus guaranteeing the subsequent in situ calcination reaction, which produced well-dispersed Ni and Co3O4 nanoparticles. Moreover, the N-doped carbon matrix formed at high temperatures could effectively prevent the aggregation and coalescence, and regulate the electronic configuration of active species. Benefiting from the synergistic effect between the Ni, Co3O4, and NC species, the obtained Ni/Co3O4@NC hybrids exhibited enhanced OER activities and remarkable stability in an alkaline solution with a smaller overpotential of 350 m V to afford 10 m A cm-2, lower Tafel slope of 52.27 m V dec-1, smaller charge-transfer resistance, and higher double-layer capacitance of 25.53 m F cm-2 compared to those of unary Co3O4@NC or Ni@NC metal hybrids. Therefore, this paper presents a facile strategy for designing other heteroatom-doped oxides coupled with ideal carbon materials as electrocatalysts for the OER.展开更多
Developing a facile approach based on transition metal-based Prussian blue(PB)and its analogues(PBAs)with core-shell nanostructure is a very promising choice for constructing cost-effective electrocatalysts for oxygen...Developing a facile approach based on transition metal-based Prussian blue(PB)and its analogues(PBAs)with core-shell nanostructure is a very promising choice for constructing cost-effective electrocatalysts for oxygen evolution reaction(OER).Herein,a bimetallic core-shell structure with open cages of Fe-doped CoP(Fe-CoP cage)has been synthesized using CoFe-PBA cage-4 as precursor through a facile hydrothermal method and following phosphating process.Interestingly,there is an open hole in each face center of Fe-CoP cage,which suggests the more exposure of active sites for OER.Electrochemical measurements show that Fe-CoP cage can afford a current density of 10 mA cm-2 at a low overpotential(300 mV),which is better than that of RuO2.The excellent performance can be attributed to Fe doping composition and unique open-cage core-shell structure.The synergistic effect derived from bimetallic active for OER has been discussed.And its great catalytic stability has been evaluated via 1000 cycles of CV and chronoamperometry measurement.This work provides a potential method to design multiple transitional metal-doping electrocatalysts with complex framework derived from PBAs for water splitting.展开更多
Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-Co...Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres(NCs,Nb-CoSe@NC)was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER.Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER.In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC.The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm–2,which is smaller than that of the most doped catalysts.In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC.Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained.This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.展开更多
The green production of hydrogen from electrocatalytic water splitting is an important base and promising direction for the future of the large-scale application of hydrogen energy.The key of green hydrogen evolution ...The green production of hydrogen from electrocatalytic water splitting is an important base and promising direction for the future of the large-scale application of hydrogen energy.The key of green hydrogen evolution depends on the development of low-cost and highly active electrocatalysts.Molybdenum carbides(MoxC),as a typical of earth-abundant transition-metal material,have accumulated great attention due to their low cost,earth abundance,electrical conductivity,similar d-band state to Pt,and regulated morphology/electronic structures.In this paper,recent researches focusing on MoxC for efficient HER in a wide pH range are summarized from respects of modulation of unique morphology,electronic structure,and electrode interface step by step.Briefly,modulation of morphology influence the apparent activity of catalyst,modulation of electronic structure of active sites by heteroatom doping and designing heterointerface boost intrinsic HER kinetics,and modulation of electrode interface via hybridization of MoxC structures with carbon materials can ensure the fast electron transfer and boost the activity.Besides the above methods discussed,perspective and challenges of designing MoxC as the substitute of Pt-based electrocatalyst for practical hydrogen generation in a wide pH range are pointed out.展开更多
The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to...The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to controllably create the high-density interface of double sites for optimal synergistic effect.Herein, we reported a simple chemical oxidation-induced surface reconfiguration strategy to obtain the interface-rich Fe_(3)O_(4)-FeS nanoarray supported on iron foam(Fe_(3)O_(4)-FeS/IF) using FeS nanosheets as precursors. The abundant Fe_(3)O_(4)-FeS interfaces could improve the dispersion of active sites and facilitate the electron transfer, leading to enhanced hydrogen evolution efficiency. And meanwhile, by altering the oxidation temperature, the content of S and O could be effectively controlled, further achieving the ratio optimization of Fe_(3)O_(4)to FeS. Synchrotron-based X-ray absorption near-edge structure, X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy consistently confirm the changes of electronic structure and d-band center of Fe_(3)O_(4)-FeS after chemical oxidation. Consequently, Fe_(3)O_(4)-FeS/IF exhibits excellent alkaline HER activity with a low overpotential of 120.8 mV to reach 20 mA cm^(-2),and remains stable ranging from 10, 20 to 50 mA cm^(-2) for each 20 h, respectively. Therefore, the facile and controllable chemical oxidation may be an effective strategy for designing high-density interfaces of transition metal-based sulfides towards alkaline HER.展开更多
The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owin...The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce^(3+)/Ce4+.Herein,Ce0.21@Co(OH)_(2) with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER.Firstly,the obtained core-shell structure composed of vertical loose Co(OH)_(2) sheets not only exposes a large number of active sites,but also provides channels for Ce doping.Secondly,the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)_(2),obtaining Cex@Co(OH)_(2) with well dispersion and close integration.The intimated interaction between Ce and Co species may provide the"d-f electronic ladders"for accelerating electron transfer of the catalytic surface.Meanwhile,Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen,which is considered to be the rate-determining step for OER.The electrochemical measurements confirmed the low overpotential of 300 m V at 10 m A cm^(-2) and great stability of Ce0.21@Co(OH)_(2) for OER.This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.展开更多
Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/C...Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.展开更多
The ternary cobalt-nickel-iron phosphide nanocubes (P-Co0.9Ni0.9Fe1.2 NCs) with high intrinsic activity, conductivity, defect concentration and optimized ratio have been realized through a facile phosphorization treat...The ternary cobalt-nickel-iron phosphide nanocubes (P-Co0.9Ni0.9Fe1.2 NCs) with high intrinsic activity, conductivity, defect concentration and optimized ratio have been realized through a facile phosphorization treatment using ternary cobalt-nickel-iron nanocubes of Prussian blue analogs (PBA) as a precursor. The scanning electron microscopy and transmission electron microscopy results show that the P-Co0.9Ni0.9Fe1.2 NCs maintain a cubic structure with a rough surface, implying the rich surface defects as exposed active sites. The thermal phosphorization of the ternary PBA precursor not only provids carbon doping but also leads to the in situ construction of surface defects on the NCs. The carbon doping from the PBA precursor lowers the charge transfer resistance and optimizes the electronic transformation. The synergistic effect among the ternary metal ions and rich defects contributes to the enhanced electrocatalytic performance . The P-Co0.9Ni0.9Fe1.2NCs achieve low overpotentials of -200.7 and 273.1 mV at a current density of 10 mA cm^-2 for the hydrogen evolution reaction and the oxygen evolution reaction, respectively. The potential of overall water splitting reaches 1.52 V at a current density of 10 mA cm^-2. The longterm stability of the electrocatalysts was also evaluated. This work provides a facile method to design efficient transitionmetal- based bifunctional electrocatalysts for overall water splitting.展开更多
Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporat...Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporating conductive support or foreign elements have been adopted to develop efficient electrocat- alysts. Herein, we summarize recent progresses and propose in-situ electrochemical activation as a new pretreating technique for enhanced catalytic performances. The activation techniques mainly comprise facile electrochemical processes such as anodic oxidation, cathodic reduction, etching, lithium-assisted tuning and counter electrode electro-dissolution. During these electrochemicaI treatments, the catalyst surfaces are modified from bulk phase, which can tune local electronic structures, create more active spe- cies. enlarge surface area and thus improve the catalytic performances. Meanwhile, this technique can couple the atomic, electronic structures with electrocatalysis mechanisms for water splitting. Compared to traditional chemical treatment, the in-situ electrochemical activation techniques have superior advantages such as facile operation, mild environment, variable control, high efficiency and flex- ibility. This review may provide guidance for improving water electrolysis efficiencies and hold promis- ing for application in many other energy-conversion fields such as supercapacitors, fuel cells and batteries.展开更多
The development of high-efficiency electrocatalysts for overall water splitting under large current density is significant and challenging.Herein,a high-performing Fe-doped MoNi alloy catalyst(M-H-MoNiFe-50)abundant w...The development of high-efficiency electrocatalysts for overall water splitting under large current density is significant and challenging.Herein,a high-performing Fe-doped MoNi alloy catalyst(M-H-MoNiFe-50)abundant with flower-like nanorods assemblies has been prepared by high-pressure microwave reaction and hydrogen reduction.Firstly,Fe doped NiMoO_(4) precursor(M-MoNiFe-50)was synthesized by microwave fast heating,ensuring the robustness of nanorods,which owns larger area and improved catalytic activity than that by conventional hydrothermal method.Secondly,M-MoNiFe-50 was reduced in H_(2)/Ar to fabricate Fe-incorporated MoNi_(4) alloys(M-H-MoNiFe-50),greatly enhancing the conductivity and facilitating hydrogen/oxygen spillover.The final M-H-MoNiFe-50 exhibits remarkable activity for alkaline/acidic hydrogen evolution reaction and oxygen evolution reaction with low overpotential of 208(alkaline),254(acid)and 347 mV at 1,000 mA·cm^(−2).Moreover,an alkaline water electrolyzer is established using M-H-MoNiFe-50 as anode and cathode,generating a current density of 100 mA·cm^(−2) at 1.58 V with encouraging durability of 50 h at 1,000 mA·cm^(−2).The extraordinary water splitting performance can be chalked up to the large surface area,favorable charge transfer,modified electron distribution,intrinsic robustness as well as an efficient gas spillover of M-H-MoNiFe-50.The final electrocatalyst has great prospects for practical application and confirms the significance of Fe doping,microwave method and spillover effect for catalytic performance improvement.展开更多
Designing the specific crystal phase with better intrinsic activity and more active sites is a very promising strategy for earth-abundant electrocatalysts for oxygen evolution reaction(OER).Herein,a facile two-step me...Designing the specific crystal phase with better intrinsic activity and more active sites is a very promising strategy for earth-abundant electrocatalysts for oxygen evolution reaction(OER).Herein,a facile two-step method including the high-pressure microwave and the hydrothermal sulfurization is adopted to prepare the WS_(x)/Ni_(9)S_(8) hetero-catalyst on nickel foam(WS_(x)/Ni_(9)S_(8)/NF).Firstly,WO3 polyhedrons homogeneously cover the surface of NF through the high-pressure microwave hydrothermal process.Secondly,WS_(x)/Ni_(9)S_(8) nanoparticles on the surface of NF can be synthesized after a hydrothermal sulfurization,which has been confirmed by scanning electron microscopy(SEM) elemental mapping and high-resolution transmission electron microscopy(HRTEM).The amorphous WSx and Ni9 S8 phase may provide the dual active sites for OER.The electrochemical measurements show that WS_(x)/Ni_(9)S_(8)/NF has superior OER activity with a low overpotential of 320 mV at the current density of 100 mA·cm^(-2),better than those of other samples.The enhanced OER performance may be due to the synergistic catalysis from Ni9 S8 phase and high valence of W.Owing to the stable structure of Ni9 S8,the long-term stability of WS_(x)/Ni_(9)S_(8)/NF for at least 10 h can be obtained.This work may provide a new approach for the doped nickel sulfides crystal phase through high-pressure microwave hydrothermal assistance for OER.展开更多
Electrocatalytic water splitting to produce hydrogen is an eco-friendly way to achieve sustainable utilization of renewable energy.The industrial application of water electrolysis, which is severely limited by slow ki...Electrocatalytic water splitting to produce hydrogen is an eco-friendly way to achieve sustainable utilization of renewable energy.The industrial application of water electrolysis, which is severely limited by slow kinetic reactions on electrode surfaces, requires the development of highly reactive, low-cost and stable electrocatalytic materials. Transition metal borides/borates have recently emerged as promising electrocatalytic materials for catalyzing hydrogen/oxygen evolution reactions(HER/OER) in inexpensive electrolyzers. However, so far, there has been little comprehensive summary of transition metal borides/borates. Here, this review provides the latest research progress on transition metal borides/borates for electrocatalytic water splitting. The structural characteristics of transition metal borides/borates and their synthesis methods in recent years are discussed. Then, the theoretical and experimental progress of transition metal borides including single-metal borides, multi-metal borides, borate derived and other nanocomposites containing boron(boron-doped nanocomposites/substrate with boron) in electrocatalytic reaction and the role of boron in regulating electrocatalytic performance are further emphasized. Finally, the potential challenges and future prospects of transition metal borides/borates in electrocatalysis are presented.展开更多
The heterojunction interfacial modulation of FeP is an effective strategy to regulate the intrinsic activity and stability, which is a major challenge to promote the industrial application of FeP-based electrocatalyst...The heterojunction interfacial modulation of FeP is an effective strategy to regulate the intrinsic activity and stability, which is a major challenge to promote the industrial application of FeP-based electrocatalysts. Herein, hollow Fe_(4)C/FeP box with heterojunction interface and carbon armor is successfully synthesized, which can expose numerous active sites and protect catalyst from corrosion. Electrochemical measurements show that Fe_(4)C/FeP exhibits excellent hydrogen evolution activity and stability. It only needs 180 mV to achieve the current density of 10 mA cm^(-2). The high-activity may be due to the synergistic effects of porous framework, graphitic carbon coating and heterojunction structure of FeC and FeP, which optimize the electronic structure and accelerates electron transfer. In addition, the target catalyst can withstand 5000 cycles of CV testing without significant change in properties. The excellent stability may be attributed to the graphitic carbon coating as the armor that can prevent the catalyst from corrosion of electrolyte. This work may provide a synthetic approach to produce a series of carbon-coated and heterojunction structure of transition metal phosphides for water splitting.展开更多
The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the ...The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the electronic properties of LaCoO_(3) by fine-tuning its crystal facet and atomic doping.LaCoO_(3) samples with oriented(110)(LCO(110))and(111)(LCO(111))facets were motivated by a capping agent(Sr^(2+)).Compared with the LCO(111)plane,the LCO(110)and Sr-doped LCO(111)(LSCO(111))planes possessed higher O 2p positions,stronger Co 3d-O 2p covalencies,and higher Co spin states by inducing CoO_(6) distortion,thus leading to superior oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performances.Specifically,the overpotentials at 10 mA cm^(−2) were 299,322,and 289 mV for LCO(110),LCO(111),and LSCO(111),respectively.In addition,the(110)crystal facet and Sr substitution bestowed enhanced stability on LaCoO_(3) due to the strengthened Co-O bonding.The present work enlightens new avenues of regulating electronic properties by crystal facet engineering and atom doping and provides a valuable reference for the electron structure-electrocatalytic activity connection for OER and HER.展开更多
Developing the high activity,low cost and robust large-current-density-based electrocatalysts is of great significance for the industrial electrolytic water splitting.However,the current range of most reported materia...Developing the high activity,low cost and robust large-current-density-based electrocatalysts is of great significance for the industrial electrolytic water splitting.However,the current range of most reported materials is small,which makes it difficult for them to play their roles in practical applications.Here,a self-supported amorphous FexNi1-xMo O4/IF treated with ammonium fluoride (AF_(0.1)-FNMO/IF) is synthesized by one-step hydrothermal method.With the help of NH4F,AF_(0.1)-FNMO/IF exhibits a vertically cross-linked nanosheet with spherical structure.Electrochemical measurement shows that AF_(0.1)-FNMO/IF affords a large current density ordeal and only need low overpotentials of 289 and 345 m V to reach a current response of 500 m A/cm ^(2)for oxygen evolution reaction and hydrogen evolution reaction,respectively,together with long-time stability (both at 500,1000 and 2000 m A/cm ^(2)) in 1.0 mol/L KOH solution.Using it as bifunctional catalyst for overall water splitting,the current densities of 100,500,1000 and1500 m A/cm ^(2)are achieved at a cell voltage of 1.71,1.88,1.94 and 1.97 V with excellent durability,which is much better than that of most published electrodes.The work provides valuable insight for designing higher activity nickel iron-based molybdate catalysts with large current density.展开更多
The effective electron and interface/structural coupling for heterostructure electrocatalyst is the key to regulating the intrinsic activity and stability for oxygen evolution reaction(OER).Herein,a facile strategy is...The effective electron and interface/structural coupling for heterostructure electrocatalyst is the key to regulating the intrinsic activity and stability for oxygen evolution reaction(OER).Herein,a facile strategy is developed to fabricate well-dispersed zerodimensional(0D)metallic Co_(9)S_(8)nanoparticles on two-dimensional(2D)FeS nanosheets,forming FeS-Co_(9)S_(8)Schottky heterostructures with abundant heterointerfaces as OER electrocatalyst.The strong electronic coupling between FeS and Co_(9)S_(8)expedites electrons flow from Fe atoms in FeS nanosheets to Co atoms in tetrahedron sites(CoTd),thereby leading to the structural integrity of the heterostructure and the constant exposure of active sites.Operando Raman spectroscopy also indicates the Co sites in the FeS-Co_(9)S_(8)Schottky heterostructure are OER active sites.Therefore,FeS-Co_(9)S_(8)heterostructure supported by iron foam(FeS-Co_(9)S_(8)/IF)shows the remarkable activity and durability,achieving an industrial-level 500 mA·cm^(−2)current density at an overpotential of only 332 mV and maintaining for 100 h.This work demonstrates that constructing Schottky heterostructure interface with strong coupling effect may be a good strategy for excellent catalytic performances.展开更多
Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effec...Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effect.Here,we made the utmost of the interaction of Fe–Ni heteroatomic pair to obtain a highly active Fe-Ni(oxy)hydroxide catalytic layer on iron foam(IF)and nickel foam(NF)by in-situ electrochemical deposition and rapid surface reconstruction,which only required 327 and 351 mV overpotential to provide a large current of 1,000 mA·cm^(−2),respectively.The results confirm that the moderate Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)formed by adjusting the Ni/Fe ratio on the catalyst surface is important to offer predominant OER performance.Fe is a key component that enhances OER activity of Ni(O)OH,but Fe-rich structural surface formed by Fe–O–Ni–O–Fe bonding is not ideal.Finally,the remarkable oxygen evolution performance of the prepared Ni2Fe(O)OH/IF and FeNi2(O)OH/NF can be chalked up to the optimized electronic structure of Fe–Ni heteroatomic bonding,the efficient gas spillover,the fast electron transport,and nanosheet clusters morphology.In summary,our work suggests a comprehensive regulation mechanism for the construction of efficient Fe-Ni(oxy)hydroxide catalytic layer on inexpensive,stable,and self-supporting metallic material surface.展开更多
基金financially supported by the National Natural Science Foundation of China(21776314)Major Program of Shandong Province Natural Science Foundation(ZR2018ZC0639)+2 种基金Shandong Provincial Natural Science Foundation(ZR2017MB059)the Fundamental Research Funds for the Central Universities(18CX05016A)Postgraduate Innovation Project of China University of Petroleum(YCX2018034)
文摘Adjusting the intrinsic activity and conductivity of electrocatalysts may be a crucial way for excellent performance for water splitting.Herein,the rational design of vanadium element doped cobalt phosphide(V-doped CoP)nanoparticles has been investigated through a facile gaseous phosphorization using cobalt vanadium oxide or hydroxide(Co-V hydr(oxy)oxide)as precursor.The physical characterization shows that the homogeneous dispersion of V element on V-doped CoP nanoparticles have obtained,which may imply the enhanced electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrochemical measurements of the prepared V-doped CoP in alkaline electrolyte demonstrate the superior electrocatalytic activity for both HER(overpotential of 235 mV@10 mA cm^-2)and OER(overpotential of 340 mV@10 mA cm^-2).Further,V-doped CoP nanoparticles used as anode and cathode simultaneously in a cell require only 370 mV to achieve a current density of 10 mA cm^-2.The outstanding electrocatalytic activity may be ascribed to the improved conductivity and intrinsic activity owing to phosphating and the doping of V element.In addition,the long-term stability of V-doped Co P has been obtained.Therefore,metal doping into transition metal-based phosphides may be a promising strategy for the remarkable bifunctional electrocatalyst for water splitting.
文摘The most energy-inefficient step in the oxygen evolution reaction(OER), which involves a complicated four-electron transfer process, limits the efficiency of the electrochemical water splitting. Here, well-defined Ni/Co3O4 nanoparticles coupled with N-doped carbon hybrids(Ni/Co3O4@NC) were synthesized via a facile impregnation-calcination method as efficient electrocatalysts for OER in alkaline media. Notably, the impregnation of the polymer with Ni and Co ions in the first step ensured the homogeneous distribution of metals, thus guaranteeing the subsequent in situ calcination reaction, which produced well-dispersed Ni and Co3O4 nanoparticles. Moreover, the N-doped carbon matrix formed at high temperatures could effectively prevent the aggregation and coalescence, and regulate the electronic configuration of active species. Benefiting from the synergistic effect between the Ni, Co3O4, and NC species, the obtained Ni/Co3O4@NC hybrids exhibited enhanced OER activities and remarkable stability in an alkaline solution with a smaller overpotential of 350 m V to afford 10 m A cm-2, lower Tafel slope of 52.27 m V dec-1, smaller charge-transfer resistance, and higher double-layer capacitance of 25.53 m F cm-2 compared to those of unary Co3O4@NC or Ni@NC metal hybrids. Therefore, this paper presents a facile strategy for designing other heteroatom-doped oxides coupled with ideal carbon materials as electrocatalysts for the OER.
基金financially supported by Shandong Provincial Natural Science Foundation(ZR2017MB059)the Fundamental Research Funds for the Central Universities(18CX05016A)Postgraduate Innovation Project of China University of Petroleum(YCX2019096)。
文摘Developing a facile approach based on transition metal-based Prussian blue(PB)and its analogues(PBAs)with core-shell nanostructure is a very promising choice for constructing cost-effective electrocatalysts for oxygen evolution reaction(OER).Herein,a bimetallic core-shell structure with open cages of Fe-doped CoP(Fe-CoP cage)has been synthesized using CoFe-PBA cage-4 as precursor through a facile hydrothermal method and following phosphating process.Interestingly,there is an open hole in each face center of Fe-CoP cage,which suggests the more exposure of active sites for OER.Electrochemical measurements show that Fe-CoP cage can afford a current density of 10 mA cm-2 at a low overpotential(300 mV),which is better than that of RuO2.The excellent performance can be attributed to Fe doping composition and unique open-cage core-shell structure.The synergistic effect derived from bimetallic active for OER has been discussed.And its great catalytic stability has been evaluated via 1000 cycles of CV and chronoamperometry measurement.This work provides a potential method to design multiple transitional metal-doping electrocatalysts with complex framework derived from PBAs for water splitting.
文摘Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres(NCs,Nb-CoSe@NC)was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER.Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER.In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC.The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm–2,which is smaller than that of the most doped catalysts.In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC.Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained.This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.
基金financial support from Shandong Provincial Natural Science Foundation(ZR2017MB059)the National Natural Science Foundation of China(21776314)the Fundamental Research Funds for the Central Universities(18CX05016A)。
文摘The green production of hydrogen from electrocatalytic water splitting is an important base and promising direction for the future of the large-scale application of hydrogen energy.The key of green hydrogen evolution depends on the development of low-cost and highly active electrocatalysts.Molybdenum carbides(MoxC),as a typical of earth-abundant transition-metal material,have accumulated great attention due to their low cost,earth abundance,electrical conductivity,similar d-band state to Pt,and regulated morphology/electronic structures.In this paper,recent researches focusing on MoxC for efficient HER in a wide pH range are summarized from respects of modulation of unique morphology,electronic structure,and electrode interface step by step.Briefly,modulation of morphology influence the apparent activity of catalyst,modulation of electronic structure of active sites by heteroatom doping and designing heterointerface boost intrinsic HER kinetics,and modulation of electrode interface via hybridization of MoxC structures with carbon materials can ensure the fast electron transfer and boost the activity.Besides the above methods discussed,perspective and challenges of designing MoxC as the substitute of Pt-based electrocatalyst for practical hydrogen generation in a wide pH range are pointed out.
基金financially supported by National Natural Science Foundation of China (52174283)the Qingdao Science and Technology Benefiting People Special Project (20-3-4-8-nsh)+1 种基金the Fundamental Research Funds for the Central Universities(20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processing and the Postgraduate Innovation Project of China University of Petroleum (YCX2020042)。
文摘The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to controllably create the high-density interface of double sites for optimal synergistic effect.Herein, we reported a simple chemical oxidation-induced surface reconfiguration strategy to obtain the interface-rich Fe_(3)O_(4)-FeS nanoarray supported on iron foam(Fe_(3)O_(4)-FeS/IF) using FeS nanosheets as precursors. The abundant Fe_(3)O_(4)-FeS interfaces could improve the dispersion of active sites and facilitate the electron transfer, leading to enhanced hydrogen evolution efficiency. And meanwhile, by altering the oxidation temperature, the content of S and O could be effectively controlled, further achieving the ratio optimization of Fe_(3)O_(4)to FeS. Synchrotron-based X-ray absorption near-edge structure, X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy consistently confirm the changes of electronic structure and d-band center of Fe_(3)O_(4)-FeS after chemical oxidation. Consequently, Fe_(3)O_(4)-FeS/IF exhibits excellent alkaline HER activity with a low overpotential of 120.8 mV to reach 20 mA cm^(-2),and remains stable ranging from 10, 20 to 50 mA cm^(-2) for each 20 h, respectively. Therefore, the facile and controllable chemical oxidation may be an effective strategy for designing high-density interfaces of transition metal-based sulfides towards alkaline HER.
基金financially supported by the National Natural Science Foundation of China(21776314)the Qingdao Science and Technology Benefiting People Special Project(20-3-4-8-nsh)+2 种基金the Fundamental Research Funds for the Central Universities(20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processingthe Postgraduate Innovation Project of China University of Petroleum(YCX2020046)。
文摘The intrinsic activity of Co(OH)_(2) for oxygen evolution reaction(OER)may be elaborately improved through the suitable valence adjustment.Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce^(3+)/Ce4+.Herein,Ce0.21@Co(OH)_(2) with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER.Firstly,the obtained core-shell structure composed of vertical loose Co(OH)_(2) sheets not only exposes a large number of active sites,but also provides channels for Ce doping.Secondly,the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)_(2),obtaining Cex@Co(OH)_(2) with well dispersion and close integration.The intimated interaction between Ce and Co species may provide the"d-f electronic ladders"for accelerating electron transfer of the catalytic surface.Meanwhile,Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen,which is considered to be the rate-determining step for OER.The electrochemical measurements confirmed the low overpotential of 300 m V at 10 m A cm^(-2) and great stability of Ce0.21@Co(OH)_(2) for OER.This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.
基金financially supported by the National Natural Science Foundation of China(Nos.52174283 and 52274308)。
文摘Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.
基金supported by the Natural Science Foundation of Shandong Province(ZR2017MB059)the Major Program of Shandong Province Natural Science Foundation(ZR2018ZC0639)+2 种基金the National Natural Science Foundation of China(21776314)the Fundamental Research Funds for the Central Universities(18CX05016A)the Postgraduate Innovation Project of China University of Petroleum(YCX2018074)
文摘The ternary cobalt-nickel-iron phosphide nanocubes (P-Co0.9Ni0.9Fe1.2 NCs) with high intrinsic activity, conductivity, defect concentration and optimized ratio have been realized through a facile phosphorization treatment using ternary cobalt-nickel-iron nanocubes of Prussian blue analogs (PBA) as a precursor. The scanning electron microscopy and transmission electron microscopy results show that the P-Co0.9Ni0.9Fe1.2 NCs maintain a cubic structure with a rough surface, implying the rich surface defects as exposed active sites. The thermal phosphorization of the ternary PBA precursor not only provids carbon doping but also leads to the in situ construction of surface defects on the NCs. The carbon doping from the PBA precursor lowers the charge transfer resistance and optimizes the electronic transformation. The synergistic effect among the ternary metal ions and rich defects contributes to the enhanced electrocatalytic performance . The P-Co0.9Ni0.9Fe1.2NCs achieve low overpotentials of -200.7 and 273.1 mV at a current density of 10 mA cm^-2 for the hydrogen evolution reaction and the oxygen evolution reaction, respectively. The potential of overall water splitting reaches 1.52 V at a current density of 10 mA cm^-2. The longterm stability of the electrocatalysts was also evaluated. This work provides a facile method to design efficient transitionmetal- based bifunctional electrocatalysts for overall water splitting.
基金financially supported by Shandong Provincial Natural Science Foundation,China (ZR2017MB059)the National Natural Science Foundation of China (21776314)the Fundamental Research Funds for the Central Universities (18CX05016A)
文摘Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporating conductive support or foreign elements have been adopted to develop efficient electrocat- alysts. Herein, we summarize recent progresses and propose in-situ electrochemical activation as a new pretreating technique for enhanced catalytic performances. The activation techniques mainly comprise facile electrochemical processes such as anodic oxidation, cathodic reduction, etching, lithium-assisted tuning and counter electrode electro-dissolution. During these electrochemicaI treatments, the catalyst surfaces are modified from bulk phase, which can tune local electronic structures, create more active spe- cies. enlarge surface area and thus improve the catalytic performances. Meanwhile, this technique can couple the atomic, electronic structures with electrocatalysis mechanisms for water splitting. Compared to traditional chemical treatment, the in-situ electrochemical activation techniques have superior advantages such as facile operation, mild environment, variable control, high efficiency and flex- ibility. This review may provide guidance for improving water electrolysis efficiencies and hold promis- ing for application in many other energy-conversion fields such as supercapacitors, fuel cells and batteries.
基金supported by the National Natural Science Foundation of China(No.52174283)Qingdao Science and Technology Benefiting People Special Project(No.20-3-4-8-nsh)+1 种基金the Fundamental Research Funds for the Central Universities(No.20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processing and the Postgraduate Innovation Project of China University of Petroleum(No.YCX2020046).
文摘The development of high-efficiency electrocatalysts for overall water splitting under large current density is significant and challenging.Herein,a high-performing Fe-doped MoNi alloy catalyst(M-H-MoNiFe-50)abundant with flower-like nanorods assemblies has been prepared by high-pressure microwave reaction and hydrogen reduction.Firstly,Fe doped NiMoO_(4) precursor(M-MoNiFe-50)was synthesized by microwave fast heating,ensuring the robustness of nanorods,which owns larger area and improved catalytic activity than that by conventional hydrothermal method.Secondly,M-MoNiFe-50 was reduced in H_(2)/Ar to fabricate Fe-incorporated MoNi_(4) alloys(M-H-MoNiFe-50),greatly enhancing the conductivity and facilitating hydrogen/oxygen spillover.The final M-H-MoNiFe-50 exhibits remarkable activity for alkaline/acidic hydrogen evolution reaction and oxygen evolution reaction with low overpotential of 208(alkaline),254(acid)and 347 mV at 1,000 mA·cm^(−2).Moreover,an alkaline water electrolyzer is established using M-H-MoNiFe-50 as anode and cathode,generating a current density of 100 mA·cm^(−2) at 1.58 V with encouraging durability of 50 h at 1,000 mA·cm^(−2).The extraordinary water splitting performance can be chalked up to the large surface area,favorable charge transfer,modified electron distribution,intrinsic robustness as well as an efficient gas spillover of M-H-MoNiFe-50.The final electrocatalyst has great prospects for practical application and confirms the significance of Fe doping,microwave method and spillover effect for catalytic performance improvement.
基金financially supported by Qingdao Science and Technology Benefiting People Special Project (No. 20-3-4-8-nsh)the Fundamental Research Funds for the Central Universities (No.20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processing and China University of Petroleum Training Program of Innovation and Entrepreneurship for Undergraduates (No.201910425018)。
文摘Designing the specific crystal phase with better intrinsic activity and more active sites is a very promising strategy for earth-abundant electrocatalysts for oxygen evolution reaction(OER).Herein,a facile two-step method including the high-pressure microwave and the hydrothermal sulfurization is adopted to prepare the WS_(x)/Ni_(9)S_(8) hetero-catalyst on nickel foam(WS_(x)/Ni_(9)S_(8)/NF).Firstly,WO3 polyhedrons homogeneously cover the surface of NF through the high-pressure microwave hydrothermal process.Secondly,WS_(x)/Ni_(9)S_(8) nanoparticles on the surface of NF can be synthesized after a hydrothermal sulfurization,which has been confirmed by scanning electron microscopy(SEM) elemental mapping and high-resolution transmission electron microscopy(HRTEM).The amorphous WSx and Ni9 S8 phase may provide the dual active sites for OER.The electrochemical measurements show that WS_(x)/Ni_(9)S_(8)/NF has superior OER activity with a low overpotential of 320 mV at the current density of 100 mA·cm^(-2),better than those of other samples.The enhanced OER performance may be due to the synergistic catalysis from Ni9 S8 phase and high valence of W.Owing to the stable structure of Ni9 S8,the long-term stability of WS_(x)/Ni_(9)S_(8)/NF for at least 10 h can be obtained.This work may provide a new approach for the doped nickel sulfides crystal phase through high-pressure microwave hydrothermal assistance for OER.
基金financially supported by National Natural Science Foundation of China(Nos.22078362 and 21808243)the Postgraduate Innovation Engineering Project of China University of Petroleum(East China)(YCX2021063)。
文摘Electrocatalytic water splitting to produce hydrogen is an eco-friendly way to achieve sustainable utilization of renewable energy.The industrial application of water electrolysis, which is severely limited by slow kinetic reactions on electrode surfaces, requires the development of highly reactive, low-cost and stable electrocatalytic materials. Transition metal borides/borates have recently emerged as promising electrocatalytic materials for catalyzing hydrogen/oxygen evolution reactions(HER/OER) in inexpensive electrolyzers. However, so far, there has been little comprehensive summary of transition metal borides/borates. Here, this review provides the latest research progress on transition metal borides/borates for electrocatalytic water splitting. The structural characteristics of transition metal borides/borates and their synthesis methods in recent years are discussed. Then, the theoretical and experimental progress of transition metal borides including single-metal borides, multi-metal borides, borate derived and other nanocomposites containing boron(boron-doped nanocomposites/substrate with boron) in electrocatalytic reaction and the role of boron in regulating electrocatalytic performance are further emphasized. Finally, the potential challenges and future prospects of transition metal borides/borates in electrocatalysis are presented.
基金financially supported by National Natural Science Foundation of China (52174283)Innovation Fund Project for Graduate Students of China University of Petroleum (East China)(No. CXJJ-2022-23)。
文摘The heterojunction interfacial modulation of FeP is an effective strategy to regulate the intrinsic activity and stability, which is a major challenge to promote the industrial application of FeP-based electrocatalysts. Herein, hollow Fe_(4)C/FeP box with heterojunction interface and carbon armor is successfully synthesized, which can expose numerous active sites and protect catalyst from corrosion. Electrochemical measurements show that Fe_(4)C/FeP exhibits excellent hydrogen evolution activity and stability. It only needs 180 mV to achieve the current density of 10 mA cm^(-2). The high-activity may be due to the synergistic effects of porous framework, graphitic carbon coating and heterojunction structure of FeC and FeP, which optimize the electronic structure and accelerates electron transfer. In addition, the target catalyst can withstand 5000 cycles of CV testing without significant change in properties. The excellent stability may be attributed to the graphitic carbon coating as the armor that can prevent the catalyst from corrosion of electrolyte. This work may provide a synthetic approach to produce a series of carbon-coated and heterojunction structure of transition metal phosphides for water splitting.
基金supported by the National Natural Science Foundation of China(52174283)。
文摘The correlation between crystal facets and electronic configurations of perovskite is closely related to the intrinsic activity for water splitting.Herein,we proposed a unique molten-salt method(MSM)to manipulate the electronic properties of LaCoO_(3) by fine-tuning its crystal facet and atomic doping.LaCoO_(3) samples with oriented(110)(LCO(110))and(111)(LCO(111))facets were motivated by a capping agent(Sr^(2+)).Compared with the LCO(111)plane,the LCO(110)and Sr-doped LCO(111)(LSCO(111))planes possessed higher O 2p positions,stronger Co 3d-O 2p covalencies,and higher Co spin states by inducing CoO_(6) distortion,thus leading to superior oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)performances.Specifically,the overpotentials at 10 mA cm^(−2) were 299,322,and 289 mV for LCO(110),LCO(111),and LSCO(111),respectively.In addition,the(110)crystal facet and Sr substitution bestowed enhanced stability on LaCoO_(3) due to the strengthened Co-O bonding.The present work enlightens new avenues of regulating electronic properties by crystal facet engineering and atom doping and provides a valuable reference for the electron structure-electrocatalytic activity connection for OER and HER.
基金financially supported by National Natural Science Foundation of China (No. 52174283)Shandong Provincial Natural Science Foundation (No. ZR2020MB044)+1 种基金Innovation Fund Project for Graduate Students of China University of Petroleum (East China) (No. 22CX04026A)the Fundameantal Research Funds for the Central Universities。
文摘Developing the high activity,low cost and robust large-current-density-based electrocatalysts is of great significance for the industrial electrolytic water splitting.However,the current range of most reported materials is small,which makes it difficult for them to play their roles in practical applications.Here,a self-supported amorphous FexNi1-xMo O4/IF treated with ammonium fluoride (AF_(0.1)-FNMO/IF) is synthesized by one-step hydrothermal method.With the help of NH4F,AF_(0.1)-FNMO/IF exhibits a vertically cross-linked nanosheet with spherical structure.Electrochemical measurement shows that AF_(0.1)-FNMO/IF affords a large current density ordeal and only need low overpotentials of 289 and 345 m V to reach a current response of 500 m A/cm ^(2)for oxygen evolution reaction and hydrogen evolution reaction,respectively,together with long-time stability (both at 500,1000 and 2000 m A/cm ^(2)) in 1.0 mol/L KOH solution.Using it as bifunctional catalyst for overall water splitting,the current densities of 100,500,1000 and1500 m A/cm ^(2)are achieved at a cell voltage of 1.71,1.88,1.94 and 1.97 V with excellent durability,which is much better than that of most published electrodes.The work provides valuable insight for designing higher activity nickel iron-based molybdate catalysts with large current density.
基金supported by the National Natural Science Foundation of China(Nos.52274308 and 52174283)Postgraduate Innovation Engineering Project of China University of Petroleum(East China)(No.YCX2021134).
文摘The effective electron and interface/structural coupling for heterostructure electrocatalyst is the key to regulating the intrinsic activity and stability for oxygen evolution reaction(OER).Herein,a facile strategy is developed to fabricate well-dispersed zerodimensional(0D)metallic Co_(9)S_(8)nanoparticles on two-dimensional(2D)FeS nanosheets,forming FeS-Co_(9)S_(8)Schottky heterostructures with abundant heterointerfaces as OER electrocatalyst.The strong electronic coupling between FeS and Co_(9)S_(8)expedites electrons flow from Fe atoms in FeS nanosheets to Co atoms in tetrahedron sites(CoTd),thereby leading to the structural integrity of the heterostructure and the constant exposure of active sites.Operando Raman spectroscopy also indicates the Co sites in the FeS-Co_(9)S_(8)Schottky heterostructure are OER active sites.Therefore,FeS-Co_(9)S_(8)heterostructure supported by iron foam(FeS-Co_(9)S_(8)/IF)shows the remarkable activity and durability,achieving an industrial-level 500 mA·cm^(−2)current density at an overpotential of only 332 mV and maintaining for 100 h.This work demonstrates that constructing Schottky heterostructure interface with strong coupling effect may be a good strategy for excellent catalytic performances.
基金the National Natural Science Foundation of China(No.52174283)the Shandong Provincial Natural Science Foundation(No.ZR2020MB044)Postgraduate Innovation Engineering Project of China University of Petroleum(East China)(No.YCX2021147).
文摘Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic effect.Here,we made the utmost of the interaction of Fe–Ni heteroatomic pair to obtain a highly active Fe-Ni(oxy)hydroxide catalytic layer on iron foam(IF)and nickel foam(NF)by in-situ electrochemical deposition and rapid surface reconstruction,which only required 327 and 351 mV overpotential to provide a large current of 1,000 mA·cm^(−2),respectively.The results confirm that the moderate Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)formed by adjusting the Ni/Fe ratio on the catalyst surface is important to offer predominant OER performance.Fe is a key component that enhances OER activity of Ni(O)OH,but Fe-rich structural surface formed by Fe–O–Ni–O–Fe bonding is not ideal.Finally,the remarkable oxygen evolution performance of the prepared Ni2Fe(O)OH/IF and FeNi2(O)OH/NF can be chalked up to the optimized electronic structure of Fe–Ni heteroatomic bonding,the efficient gas spillover,the fast electron transport,and nanosheet clusters morphology.In summary,our work suggests a comprehensive regulation mechanism for the construction of efficient Fe-Ni(oxy)hydroxide catalytic layer on inexpensive,stable,and self-supporting metallic material surface.
