Iron-based superconductors(FeSCs)feature a complex phase diagram,and their diverse cleavage terminations offer a versatile platform for modulating surface electronic states and investigating the underlying superconduc...Iron-based superconductors(FeSCs)feature a complex phase diagram,and their diverse cleavage terminations offer a versatile platform for modulating surface electronic states and investigating the underlying superconducting mechanisms.In this study,we explore the surface modulation of KCa_(2)Fe_(4)As_(4)F_(2)using scanning tunneling microscopy/spectroscopy.Cryogenically cleaved surfaces reveal multiple configurations,including√2×√2 reconstruction,1×2 and 1×3 stripes,as well as nanoscale vacancies.Reducing potassium coverage induces hole doping,which shifts the density of states peak toward the Fermi level and suppresses the superconducting gap from 4.8 meV to 3.2 meV.This behavior is reminiscent of the Van Hove singularity observed in hole-doped 122-type FeSCs.The band structure does not undergo a simple rigid shift,and the evolution of superconductivity can be attributed to the interplay between surface carriers and electronic correlations.Additionally,a V-shaped gap is observed at a unique location preserving the FeAs bilayer structure,where interlayer coupling effects are likely involved.The diversity of surface structures and electronic states in K12442 enhances our understanding of FeSCs and facilitates the modulation and application of FeAs superconducting layers.展开更多
Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ recons...Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ reconstructed and converted into high-valence metal oxyhydroxides.However,a limited understanding of the effects of electro-oxidation and anion leaching has resulted in insufficient theoretical guidance for the rational design of efficient catalysts.Herein,FeSe@NiSe nanorods were fabricated for the OER using a facile hydrothermal selenization method supported on FeNi foam.In-situ Raman spectroscopy and multiple characterization techniques were employed to elucidate the mechanism of FeSe@NiSe surface evolution.Metal cations on the catalyst surface were reconstructed and converted into OER-active species Fe/NiOOH at low potential.As the applied potential increased,electro-oxidation and leaching of Se occurred,resulting in SeO_(4)^(2−)adsorption on the catalyst surface,which further enhanced catalytic activity.As a result,the reconstructed FeSe@NiSe/iron-nickel foam(INF)exhibited exceptional catalytic activity for OER,achieving an ultralow overpotential of 283 mV at a current density of 100 mA·cm^(−2).Notably,the bifunctional FeSe@NiSe/INF electrode facilitated overall water splitting,affording a current density of 10 mA·cm^(−2) only at 1.53 V,even superior to the noble RuO_(2)(+)||Pt/C(−).This work offers valuable insights into the surface evolution and electrocatalytic mechanisms of TMSs.展开更多
The sluggish kinetics of the oxygen evolution reaction(OER)severely limits the efficiency of electrochemical water splitting for sustainable hydrogen production.Developing cost-effective and efficient OER electrocatal...The sluggish kinetics of the oxygen evolution reaction(OER)severely limits the efficiency of electrochemical water splitting for sustainable hydrogen production.Developing cost-effective and efficient OER electrocatalysts based on earth-abundant elements is thus highly desirable.Herein,we report a nanoporous(CoNiFe)OOH electrocatalyst decorated with Zn(OH)_(4)^(2−)anions,synthesized via electrochemical surface reconstruction of ZnO-decorated CoNiFe medium-entropy alloys(MEAs).The reconstructed(CoNiFe)OOH adsorbed with Zn(OH)_(4)^(2−)anions serves as the real active phase,featuring abundant catalytic sites and enhanced OH−accessibility.Adsorbed Zn(OH)_(4)^(2−)anions promote OH−transfer and facilitate electron redistribution at the active sites,particularly enhancing Co site activity,as revealed by density functional theory(DFT)calculations.As a result,the optimized CoNiFeZn@NF-EO electrode exhibits outstanding OER performance,achieving a low overpotential of 264 mV at 10 mA·cm^(−2),a Tafel slope of 46.6 mV·dec^(−1),and remarkable long-term stability in alkaline electrolyte.This work provides new insights into the synergistic effect between surface reconstruction and Zn-based species,offering a promising strategy for designing high-performance OER electrocatalysts.展开更多
The surface reconstruction behavior of transition metal phosphides precursors is considered as an important method to prepare efficient oxygen evolution catalysts,but there are still significant challenges in guiding ...The surface reconstruction behavior of transition metal phosphides precursors is considered as an important method to prepare efficient oxygen evolution catalysts,but there are still significant challenges in guiding catalyst design at the atomic scale.Here,the CoP nanowire with excellent water splitting performance and stability is used as a catalytic model to study the reconstruction process.Obvious double redox signals and valence evolution behavior of the Co site are observed,corresponding to Co^(2+)/Co^(3+)and Co^(3+)/Co4+caused by auto-oxidation process.Importantly,the in situ Raman spectrum exhibits the vibration signal of Co-OH in the non-Faradaic potential interval for oxygen evolution reaction,which is considered the initial step in reconstruction process.Density functional theory and ab initio molecular dynamics are used to elucidate this process at the atomic scale:First,OH^(-)exhibits a lower adsorption energy barrier and proton desorption energy barrier at the configuration surface,which proposes the formation of a single oxygen(-O)group.Under a higher-O group coverage,the Co-P bond is destroyed along with the POx groups.Subsequently,lower P vacancy formation energy confirm that the Ni-CoP configuration can fast transform into a highly active phase.Based on the optimized reconstruction behavior and rate-limiting barrier,the Ni-CoP nanowire exhibit an excellent overpotential of 1.59 V at 10 mA cm^(-2) for overall water splitting,which demonstrates low degradation(2.62%)during the 100 mA cm^(-2) for 100 h.This work provide systematic insights into the atomic-level reconstruction mechanism of transition metal phosphides,which benefit further design of water splitting catalysts.展开更多
The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy densi...The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy density and cost-efficiency.However,these cathodes face critical challenges,including thermal instability and structural degradation at an elevated temperature,which hinder their practical application.This study introduces an advanced surface reconstruction strategy combining a LiScF_(4)coating,Sc/F surface co-doping,and a cation-mixing layer to address these issues.The LiScF_(4)coating serves as a durable protective barrier,reducing electrolyte decomposition,minimizing transition metal dissolution,and enhancing lithium-ion transport.Sc/F surface co-doping stabilizes lattice oxygen by increasing the energy barrier for oxygen vacancy formation and minimizing oxygen release,thereby suppressing phase transitions and interfacial side reactions.Additionally,the cation-mixing layer improves interfacial stability by alleviating lattice strain and supporting reversible cation migration,ensuring prolonged durability during cycling and under high-temperature conditions.These integrated modifications work synergistically to mitigate various degradation mechanisms,significantly improving the thermal stability,structural integrity,and electrochemical performance of Ni-rich cathodes.This approach offers a viable pathway for incorporating Ni-rich cathodes into advanced lithium-ion batteries,making them well-suited for applications requiring high thermal stability.Moreover,this research provides valuable guidance for the development of a multi-component modification strategy,paving the way for future innovations in energy storage materials and advancing high-performance battery technology.展开更多
Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affecte...Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.展开更多
Substituting the sluggish oxygen evolution reaction with a more thermodynamically favorable ethanol oxidation reaction(EOR)offers an opportunity to circumvent the efficiency loss in water splitting and metal-air batte...Substituting the sluggish oxygen evolution reaction with a more thermodynamically favorable ethanol oxidation reaction(EOR)offers an opportunity to circumvent the efficiency loss in water splitting and metal-air batteries.However,the effect of the dynamic surface evolution of the catalyst in operating conditions on the activity of EOR lacks comprehensive understanding.Herein,we demonstrate a tunable operational catalyst activity through the modulated redox property of nickel oxalate(NCO)by establishing a relation between the oxidation behavior of Ni,surface reconstruction,and catalyst activity.We propose a repeated chemical-electrochemical reaction mechanism of EOR on NCO,which is rigorously investigated through a combination of operando Raman and nuclear magnetic resonance.The modulation of the oxidation trend of Ni by doping heteroatoms stimulates the electrochemical oxidation of the catalyst surface to NiOOH,which alters the catalyst activity for EOR.Assembled ethanol-assisted water electrolysis cell exhibits a reduced operating voltage for hydrogen production by 200 mV with a~100% Faradaic efficiency,and zinc-ethanol-air battery showed a 287 mV decreased charge-discharge voltage window and enhanced stability for over 500 h.展开更多
The growth by molecular beam epitaxy of high quality GaAs epilayers on nonmisoriented GaAs（111）B substrates is reported.Growth control of the GaAs epilayers is achieved via in situ,real time measurement of the specu...The growth by molecular beam epitaxy of high quality GaAs epilayers on nonmisoriented GaAs（111）B substrates is reported.Growth control of the GaAs epilayers is achieved via in situ,real time measurement of the specular beam intensity of reflection high-energy electron diffraction（RHEED）.Static surface phase maps of GaAs（111）B have been generated for a variety of incident As flux and substrate temperature conditions.The dependence of GaAs（111）B surface reconstruction phases on growth parameters is discussed.The（191/2×191/2） surface reconstruction is identified to be the optimum starting surface for the latter growth of mirror-smooth epilayers.Regimes of growth conditions are optimized in terms of the static surface phase diagram and the temporal RHEED intensity oscillations.展开更多
Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn ...Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.展开更多
Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electr...Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electrocatalysts remains a formidable challenge.Here,an electrochemical activation strategy with selective etching was utilized to guide the reconstruction process of a hybrid cobalt-molybdenum oxide(CoMoO_(4)/Co_(3)O_(4)@CC)in a favorable direction to improve the OER performance.Both in-situ Raman and multiple ex-situ characterization tools demonstrate that controlled surface reconstruction can be easily achieved through Mo etching,with the formation of a dynamically stable amorphous-crystalline heterostructure.Theoretical calculations together with experimental results reveal that the synergistic effects between amorphous CoOOH and crystalline Co_(3)O_(4) are crucial in enhancing the catalytic performance.Consequently,the reconstructed CoMoO_(4)/Co_(3)O_(4)@CC exhibits a low overpotential of 250 mV to achieve a current density of 10 mA cm^(-2) in 1 M KOH,and more importantly it can be practiced in electrolytic water splitting and rechargeable zinc-air batteries devices,achieving ultra-long stability for over 500 and 1200 h,respectively.This work provides a promising route for the construction of high-performance electrocatalysts.展开更多
Palladium-based alloy catalysts have been employed as one of the potential candidates for oxygen reduc-tion reaction(ORR),but the dissolution of transition metal hinders their application.Herein,structure or-dered PdT...Palladium-based alloy catalysts have been employed as one of the potential candidates for oxygen reduc-tion reaction(ORR),but the dissolution of transition metal hinders their application.Herein,structure or-dered PdTe intermetallic with Pd shell(o-PdTe@Pd)are synthesized via an electrochemical etching driven surface reconstruction strategy.The surface reconstruction could tune the electronic structure,weaken the adsorption energy of reaction intermediates on o-PdTe@Pd,resulting in enhanced electrocatalytic ac-tivity for ORR.The mass activity of o-PdTe@Pd is about 3.3 and 2.7 times higher than that of Pd/C in acid and alkaline,respectively.Besides,the half-potentials for ORR decay only about 44 mV and 12 mV after 30 k cycles accelerated durability test in acid and alkaline media,respectively.The enhanced dura-bility originates from the resistance of Te atoms dissolve in the ordered PdTe intermetallic core and the core-shell structure.When assembled in a Zn-air battery,o-PdTe@Pd electrode delivers a higher specific capacity(794 mAh/g)and better cycling stability than Pt/C.展开更多
In this study we performed density functional theory calculations of the adsorption of oxygen on theε-Fe_(2)surfaces to investigate the Wulff construction evolution at different oxygen coverage(θ_(O))and potential(...In this study we performed density functional theory calculations of the adsorption of oxygen on theε-Fe_(2)surfaces to investigate the Wulff construction evolution at different oxygen coverage(θ_(O))and potential(μ_(O))as well as the mechanism of oxygen removal.At low oxygen coverage(θ_(O)=0.25)and potential(μ_(O)<-7.1 eV),the(■)facets with high activity remain the high exposure(55%to 90%)while the inert(101)facets contribute less than 25%.With increasing theμ_(O)andθ_(O),the(■)and(100)become the main exposing facets.Considering the reaction condition(300℃,1000 kPa,V(CO)/V(H_(2))=1),theμo is determined as-7.5 eV.Thus,theε-Fe_(2)exposes mainly the(■)surfaces indicating its antioxidation ability.Oxygen removal mechanisms indicate that the adsorbed oxygen is easily removed on(■)surface with a barrier of 1.33 eV in good agreement with the simulated Wulff constructions.展开更多
Ocular surface disease(OSD)can have a severe impact on patients as it can lead to visual impairment and persistent discomfort.Ocular surface reconstruction(OSR)is an approach to the management of ocular diseases that ...Ocular surface disease(OSD)can have a severe impact on patients as it can lead to visual impairment and persistent discomfort.Ocular surface reconstruction(OSR)is an approach to the management of ocular diseases that cause structural damage to the ocular surface.OSR encompasses both medical and surgical treatment options.In this review,we discuss the medical and surgical strategies used in OSR.Medical management often aims to treat tear insufficiency,inflammation,and keratinization.Surgical treatments may be employed for a variety of reasons,including failure of medical management.This may include improving the oculo-palpebral structures in order to improve lid positioning and tear film.Additional therapies focus on improving tear production,such as through salivary gland transplantation.In situations where the ocular surface is so severely damaged that there is loss of limbal stem cells,limbal stem cell transplant(LSCT)may be indicated.Other surgeries such as amniotic membrane transplant(AMT)and conjunctival flaps(CFs)can help promote corneal healing.Finally,in severe situations where the cornea is beyond salvage,corneal transplantation,such as a penetrating keratoplasty(PKP),can be considered.OSR often requires a combination of medical and surgical approaches targeted to each specific patient’s presentation in order to achieve optimal outcomes.展开更多
Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water splitting.However,the structure evolution in alkaline hydrogen evolution reaction lacks...Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water splitting.However,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains disputable.Herein,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline electrolyte.The Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current densities.Further,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic performance.Our study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.展开更多
Ocular surface disease(OSD)encompasses a diverse range of disorders that impact the ocular tear film and integrity of the ocular surface including the cornea,conjunctiva,lacrimal glands,tear film and eyelids.As the ma...Ocular surface disease(OSD)encompasses a diverse range of disorders that impact the ocular tear film and integrity of the ocular surface including the cornea,conjunctiva,lacrimal glands,tear film and eyelids.As the main functions of the ocular surface are to maintain corneal transparency and hydration and protection of the corneal and conjunctival epithelium,the loss of ocular homeostasis leads to serious clinical manifestations.展开更多
Nickel-rich transition-metal oxides are widely regarded as promising cathode materials for high-energydensity lithium-ion batteries for emerging electric vehicles. However, achieving high energy density in Ni-rich cat...Nickel-rich transition-metal oxides are widely regarded as promising cathode materials for high-energydensity lithium-ion batteries for emerging electric vehicles. However, achieving high energy density in Ni-rich cathodes is accompanied by substantial safety and cycle-life obstacles. The major issues of Ni-rich cathodes at high working potentials are originated from the unstable cathode-electrolyte interface, while the underlying mechanism of parasitic reactions towards surface reconstructions of cathode materials is not well understood. In this work, we controlled the Li_(2)CO_(3) impurity content on LiNi_(0.83)Mn_(0.1)Co_(0.07)O_(2) cathodes using air, tank-air, and O_(2) synthesis environments. Home-built high-precision leakage current and on-line electrochemical mass spectroscopy experiments verify that Li_(2)CO_(3) impurity is a significant promoter of parasitic reactions on Ni-rich cathodes. The rate of parasitic reactions is strongly correlated to Li_(2)CO_(3) content and severe performance deterioration of Ni83 cathodes.The post-mortem characterizations via high-resolution transition electron microscope and X-ray photoelectron spectroscopy depth profiles reveal that parasitic reactions promote more Ni reduction and O deficiency and even rock-salt phase transformation at the surface of cathode materials. Our observation suggests that surface reconstructions have a strong affiliation to parasitic reactions that create chemically acidic environment to etch away the lattice oxygen and offer the electrical charge to reduce the valence state of transition metal. Thus, this study advances our understanding on surface reconstructions of Nirich cathodes and prepares us for searching for rational strategies.展开更多
A new method for solving the tiling problem of surface reconstruction is proposed. The proposed method uses a snake algorithm to segment the original images, the contours are then transformed into strings by Freeman＇...A new method for solving the tiling problem of surface reconstruction is proposed. The proposed method uses a snake algorithm to segment the original images, the contours are then transformed into strings by Freeman＇ s code. Symbolic string matching technique is applied to establish a correspondence between the two consecutive contours. The surface is composed of the pieces reconstructed from the correspondence points. Experimental results show that the proposed method exhibits a good behavior for the quality of surface reconstruction and its time complexity is proportional to mn where m and n are the numbers of vertices of the two consecutive slices, respectively.展开更多
TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the ...TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the hydrogen storage capacity and kinetics of TiFe alloys,drastically limiting their practical application in hydrogen storage.Consequently,in this study,we investigated the hydrogen absorption kinetics and cycling performance of the TiFe_(0.9) alloy in the presence of common impurity gases(including CH4,CO,CO_(2),and O_(2))and determined the corresponding poisoning mechanisms.Specifically,we found that CH4 did not react with the alloy but acted through physical coverage.In contrast,CO and CO_(2) occupy the active sites for H_(2),significantly impeding the dissociation and absorption of H_(2).In addition,O_(2) reacts directly with the alloy to form a passivating layer that prevents hydrogen absorption.These findings were fur-ther corroborated by in situ Fourier transform infrared spectrometry(FTIR)and density functional theory(DFT).The relationship between the adsorption energies of the impurity gases and hydrogen obtained through DFT calculations complements the experimental results.Un-derstanding these poisoning behaviors is crucial for designing Ti-based high-entropy hydrogen storage alloy alloys with enhanced resist-ance to poisoning.展开更多
The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the paral...The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the parallel and vertical channels, and the surface reconstructions of Sn（111） induced by oxygen adsorption are studied. Based on this, the adsorption behaviours of O2 on X（111） （X=Si, Ge, Sn, Pb） surfaces are analysed, and the most stable adsorption channels of O2 on X（111） （X=Si, Ge, Sn, Pb） are identified. The surface reconstructions and electron distributions along the most stable adsorption channels are discussed and compared. The results show that the O2 adsorption ability declines gradually and the amount of charge transferred decreases with the enhancement of metallicity.展开更多
The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient el...The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1611103 and 2022YFA1403203)the Innovation Program for Quantum Science and Technology(Grant Nos.2024ZD0301300 and 2021ZD0302802)the National Natural Science Foundation of China(Grant Nos.12474128,12374133,12204008,and 12104004)。
文摘Iron-based superconductors(FeSCs)feature a complex phase diagram,and their diverse cleavage terminations offer a versatile platform for modulating surface electronic states and investigating the underlying superconducting mechanisms.In this study,we explore the surface modulation of KCa_(2)Fe_(4)As_(4)F_(2)using scanning tunneling microscopy/spectroscopy.Cryogenically cleaved surfaces reveal multiple configurations,including√2×√2 reconstruction,1×2 and 1×3 stripes,as well as nanoscale vacancies.Reducing potassium coverage induces hole doping,which shifts the density of states peak toward the Fermi level and suppresses the superconducting gap from 4.8 meV to 3.2 meV.This behavior is reminiscent of the Van Hove singularity observed in hole-doped 122-type FeSCs.The band structure does not undergo a simple rigid shift,and the evolution of superconductivity can be attributed to the interplay between surface carriers and electronic correlations.Additionally,a V-shaped gap is observed at a unique location preserving the FeAs bilayer structure,where interlayer coupling effects are likely involved.The diversity of surface structures and electronic states in K12442 enhances our understanding of FeSCs and facilitates the modulation and application of FeAs superconducting layers.
基金supported by the National Natural Science Foundation of China(No.22469018)the Natural Science Basic Research Program of Department of Science and Technology of Shaanxi Province(Nos.2023-JC-ZD-22 and 2023-JC-YB-404)the Scientific Research Startup Program for Introduced Talents of Shaanxi University of Technology(Nos.SLGRCQD2303 and SLGRCQD2306).
文摘Transition metal selenides(TMSs)are effective pre-electrocatalysts and are commonly used in electrochemical processes.During the electrocatalytic oxygen evolution reaction(OER),metal cations in TMSs are in-situ reconstructed and converted into high-valence metal oxyhydroxides.However,a limited understanding of the effects of electro-oxidation and anion leaching has resulted in insufficient theoretical guidance for the rational design of efficient catalysts.Herein,FeSe@NiSe nanorods were fabricated for the OER using a facile hydrothermal selenization method supported on FeNi foam.In-situ Raman spectroscopy and multiple characterization techniques were employed to elucidate the mechanism of FeSe@NiSe surface evolution.Metal cations on the catalyst surface were reconstructed and converted into OER-active species Fe/NiOOH at low potential.As the applied potential increased,electro-oxidation and leaching of Se occurred,resulting in SeO_(4)^(2−)adsorption on the catalyst surface,which further enhanced catalytic activity.As a result,the reconstructed FeSe@NiSe/iron-nickel foam(INF)exhibited exceptional catalytic activity for OER,achieving an ultralow overpotential of 283 mV at a current density of 100 mA·cm^(−2).Notably,the bifunctional FeSe@NiSe/INF electrode facilitated overall water splitting,affording a current density of 10 mA·cm^(−2) only at 1.53 V,even superior to the noble RuO_(2)(+)||Pt/C(−).This work offers valuable insights into the surface evolution and electrocatalytic mechanisms of TMSs.
基金supported by the National Natural Science Foundation of China(Nos.52202093 and 52304325)the Natural Science Research of Jiangsu Higher Education Institutions of China(No.22KJB430021)Jiangsu Provincial Double Innovation Doctor Program(No.JSSCBS20221258).
文摘The sluggish kinetics of the oxygen evolution reaction(OER)severely limits the efficiency of electrochemical water splitting for sustainable hydrogen production.Developing cost-effective and efficient OER electrocatalysts based on earth-abundant elements is thus highly desirable.Herein,we report a nanoporous(CoNiFe)OOH electrocatalyst decorated with Zn(OH)_(4)^(2−)anions,synthesized via electrochemical surface reconstruction of ZnO-decorated CoNiFe medium-entropy alloys(MEAs).The reconstructed(CoNiFe)OOH adsorbed with Zn(OH)_(4)^(2−)anions serves as the real active phase,featuring abundant catalytic sites and enhanced OH−accessibility.Adsorbed Zn(OH)_(4)^(2−)anions promote OH−transfer and facilitate electron redistribution at the active sites,particularly enhancing Co site activity,as revealed by density functional theory(DFT)calculations.As a result,the optimized CoNiFeZn@NF-EO electrode exhibits outstanding OER performance,achieving a low overpotential of 264 mV at 10 mA·cm^(−2),a Tafel slope of 46.6 mV·dec^(−1),and remarkable long-term stability in alkaline electrolyte.This work provides new insights into the synergistic effect between surface reconstruction and Zn-based species,offering a promising strategy for designing high-performance OER electrocatalysts.
基金the National Natural Science Foundation of China(12025503,U23B2072,12105208)the Fundamental Research Funds for the Center Universities(2042024kf0001)。
文摘The surface reconstruction behavior of transition metal phosphides precursors is considered as an important method to prepare efficient oxygen evolution catalysts,but there are still significant challenges in guiding catalyst design at the atomic scale.Here,the CoP nanowire with excellent water splitting performance and stability is used as a catalytic model to study the reconstruction process.Obvious double redox signals and valence evolution behavior of the Co site are observed,corresponding to Co^(2+)/Co^(3+)and Co^(3+)/Co4+caused by auto-oxidation process.Importantly,the in situ Raman spectrum exhibits the vibration signal of Co-OH in the non-Faradaic potential interval for oxygen evolution reaction,which is considered the initial step in reconstruction process.Density functional theory and ab initio molecular dynamics are used to elucidate this process at the atomic scale:First,OH^(-)exhibits a lower adsorption energy barrier and proton desorption energy barrier at the configuration surface,which proposes the formation of a single oxygen(-O)group.Under a higher-O group coverage,the Co-P bond is destroyed along with the POx groups.Subsequently,lower P vacancy formation energy confirm that the Ni-CoP configuration can fast transform into a highly active phase.Based on the optimized reconstruction behavior and rate-limiting barrier,the Ni-CoP nanowire exhibit an excellent overpotential of 1.59 V at 10 mA cm^(-2) for overall water splitting,which demonstrates low degradation(2.62%)during the 100 mA cm^(-2) for 100 h.This work provide systematic insights into the atomic-level reconstruction mechanism of transition metal phosphides,which benefit further design of water splitting catalysts.
基金supported by the National Natural Science Foundation of China(22179008)support from the Beijing Nova Program(20230484241)+1 种基金support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)。
文摘The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy density and cost-efficiency.However,these cathodes face critical challenges,including thermal instability and structural degradation at an elevated temperature,which hinder their practical application.This study introduces an advanced surface reconstruction strategy combining a LiScF_(4)coating,Sc/F surface co-doping,and a cation-mixing layer to address these issues.The LiScF_(4)coating serves as a durable protective barrier,reducing electrolyte decomposition,minimizing transition metal dissolution,and enhancing lithium-ion transport.Sc/F surface co-doping stabilizes lattice oxygen by increasing the energy barrier for oxygen vacancy formation and minimizing oxygen release,thereby suppressing phase transitions and interfacial side reactions.Additionally,the cation-mixing layer improves interfacial stability by alleviating lattice strain and supporting reversible cation migration,ensuring prolonged durability during cycling and under high-temperature conditions.These integrated modifications work synergistically to mitigate various degradation mechanisms,significantly improving the thermal stability,structural integrity,and electrochemical performance of Ni-rich cathodes.This approach offers a viable pathway for incorporating Ni-rich cathodes into advanced lithium-ion batteries,making them well-suited for applications requiring high thermal stability.Moreover,this research provides valuable guidance for the development of a multi-component modification strategy,paving the way for future innovations in energy storage materials and advancing high-performance battery technology.
基金financially supported by the National Natural Science Foundation of China(Grant No.52073106)。
文摘Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.
基金supported by the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(NRF-2022M3H4A1A04076616 and NRF-2022M3H4A1A01008918)a cooperation project of“Basic project(referring to projects performed with the budget directly contributed by the Government to achieve the purposes of establishment of Government–funded research Institutes)”supported by the Korea Research Institute of Chemical Technology(KRICT).
文摘Substituting the sluggish oxygen evolution reaction with a more thermodynamically favorable ethanol oxidation reaction(EOR)offers an opportunity to circumvent the efficiency loss in water splitting and metal-air batteries.However,the effect of the dynamic surface evolution of the catalyst in operating conditions on the activity of EOR lacks comprehensive understanding.Herein,we demonstrate a tunable operational catalyst activity through the modulated redox property of nickel oxalate(NCO)by establishing a relation between the oxidation behavior of Ni,surface reconstruction,and catalyst activity.We propose a repeated chemical-electrochemical reaction mechanism of EOR on NCO,which is rigorously investigated through a combination of operando Raman and nuclear magnetic resonance.The modulation of the oxidation trend of Ni by doping heteroatoms stimulates the electrochemical oxidation of the catalyst surface to NiOOH,which alters the catalyst activity for EOR.Assembled ethanol-assisted water electrolysis cell exhibits a reduced operating voltage for hydrogen production by 200 mV with a~100% Faradaic efficiency,and zinc-ethanol-air battery showed a 287 mV decreased charge-discharge voltage window and enhanced stability for over 500 h.
基金Project supported by the National Natural Science Foundation of China(No.61076004)the Natural Science Foundation of Hebei Province,China(No.E2009000050)
文摘The growth by molecular beam epitaxy of high quality GaAs epilayers on nonmisoriented GaAs（111）B substrates is reported.Growth control of the GaAs epilayers is achieved via in situ,real time measurement of the specular beam intensity of reflection high-energy electron diffraction（RHEED）.Static surface phase maps of GaAs（111）B have been generated for a variety of incident As flux and substrate temperature conditions.The dependence of GaAs（111）B surface reconstruction phases on growth parameters is discussed.The（191/2×191/2） surface reconstruction is identified to be the optimum starting surface for the latter growth of mirror-smooth epilayers.Regimes of growth conditions are optimized in terms of the static surface phase diagram and the temporal RHEED intensity oscillations.
基金supported by the National Key Research and Development Program of China(2022YFE0206300)the National Natural Science Foundation of China(22209047,U21A2081,22075074)+2 种基金Natural Science Foundation of Hunan Province(2020JJ5035)Hunan Provincial Department of Education Outstanding Youth Project(23B0037)Macao Science and Technology Development Fund(Macao SAR,FDCT-0096/2020/A2).
文摘Manganese cobaltite(MnCo_(2)_(4))is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into d-MnO_(2) nanosheets irreversibly,thus results in a change of the reaction mechanism with Kþion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co_(2) þions were leached when MnCo_(2)_(4) was equilibrated in 1 mol L^(-1) HCl solution,leading to the formation of layered CoOOH on MnCo_(2)_(4) surface which is originated from the covalency competition induced selective breakage of the CoT–O bond in CoT–O–CoO and subsequent rearrangement of free Co_(6) octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo_(2)_(4)'s surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.
基金supported by the financial support of the Guangxi Science and Technology Major Projects(Guike AA23023033)。
文摘Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electrocatalysts remains a formidable challenge.Here,an electrochemical activation strategy with selective etching was utilized to guide the reconstruction process of a hybrid cobalt-molybdenum oxide(CoMoO_(4)/Co_(3)O_(4)@CC)in a favorable direction to improve the OER performance.Both in-situ Raman and multiple ex-situ characterization tools demonstrate that controlled surface reconstruction can be easily achieved through Mo etching,with the formation of a dynamically stable amorphous-crystalline heterostructure.Theoretical calculations together with experimental results reveal that the synergistic effects between amorphous CoOOH and crystalline Co_(3)O_(4) are crucial in enhancing the catalytic performance.Consequently,the reconstructed CoMoO_(4)/Co_(3)O_(4)@CC exhibits a low overpotential of 250 mV to achieve a current density of 10 mA cm^(-2) in 1 M KOH,and more importantly it can be practiced in electrolytic water splitting and rechargeable zinc-air batteries devices,achieving ultra-long stability for over 500 and 1200 h,respectively.This work provides a promising route for the construction of high-performance electrocatalysts.
基金supported by the National Natural Science Foundation(No.22279036)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003).
文摘Palladium-based alloy catalysts have been employed as one of the potential candidates for oxygen reduc-tion reaction(ORR),but the dissolution of transition metal hinders their application.Herein,structure or-dered PdTe intermetallic with Pd shell(o-PdTe@Pd)are synthesized via an electrochemical etching driven surface reconstruction strategy.The surface reconstruction could tune the electronic structure,weaken the adsorption energy of reaction intermediates on o-PdTe@Pd,resulting in enhanced electrocatalytic ac-tivity for ORR.The mass activity of o-PdTe@Pd is about 3.3 and 2.7 times higher than that of Pd/C in acid and alkaline,respectively.Besides,the half-potentials for ORR decay only about 44 mV and 12 mV after 30 k cycles accelerated durability test in acid and alkaline media,respectively.The enhanced dura-bility originates from the resistance of Te atoms dissolve in the ordered PdTe intermetallic core and the core-shell structure.When assembled in a Zn-air battery,o-PdTe@Pd electrode delivers a higher specific capacity(794 mAh/g)and better cycling stability than Pt/C.
基金The project was supported by the National Natural Science Foundation of China(21972170,22072184)the Fundamental Research Funds for the Central Universities,and South-Central Minzu University(CZY13005,CZT20010).
文摘In this study we performed density functional theory calculations of the adsorption of oxygen on theε-Fe_(2)surfaces to investigate the Wulff construction evolution at different oxygen coverage(θ_(O))and potential(μ_(O))as well as the mechanism of oxygen removal.At low oxygen coverage(θ_(O)=0.25)and potential(μ_(O)<-7.1 eV),the(■)facets with high activity remain the high exposure(55%to 90%)while the inert(101)facets contribute less than 25%.With increasing theμ_(O)andθ_(O),the(■)and(100)become the main exposing facets.Considering the reaction condition(300℃,1000 kPa,V(CO)/V(H_(2))=1),theμo is determined as-7.5 eV.Thus,theε-Fe_(2)exposes mainly the(■)surfaces indicating its antioxidation ability.Oxygen removal mechanisms indicate that the adsorbed oxygen is easily removed on(■)surface with a barrier of 1.33 eV in good agreement with the simulated Wulff constructions.
文摘Ocular surface disease(OSD)can have a severe impact on patients as it can lead to visual impairment and persistent discomfort.Ocular surface reconstruction(OSR)is an approach to the management of ocular diseases that cause structural damage to the ocular surface.OSR encompasses both medical and surgical treatment options.In this review,we discuss the medical and surgical strategies used in OSR.Medical management often aims to treat tear insufficiency,inflammation,and keratinization.Surgical treatments may be employed for a variety of reasons,including failure of medical management.This may include improving the oculo-palpebral structures in order to improve lid positioning and tear film.Additional therapies focus on improving tear production,such as through salivary gland transplantation.In situations where the ocular surface is so severely damaged that there is loss of limbal stem cells,limbal stem cell transplant(LSCT)may be indicated.Other surgeries such as amniotic membrane transplant(AMT)and conjunctival flaps(CFs)can help promote corneal healing.Finally,in severe situations where the cornea is beyond salvage,corneal transplantation,such as a penetrating keratoplasty(PKP),can be considered.OSR often requires a combination of medical and surgical approaches targeted to each specific patient’s presentation in order to achieve optimal outcomes.
基金financially supported by Basic and Applied Basic Research Project of Guangdong Province(Nos.2022A1515011438 and 2023A1515011055)Key Project of Shenzhen Basic Research(No.JCYJ2022081800003006)+2 种基金Basic Research Project of the Science and Technology Innovation Commission of Shenzhen(No.JCYJ20220531101013028)Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials(No.ZDSYS20200421111401738)China Postdoctoral Science Foundation(No.2022M722168)。
文摘Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water splitting.However,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains disputable.Herein,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline electrolyte.The Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current densities.Further,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic performance.Our study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.
文摘Ocular surface disease(OSD)encompasses a diverse range of disorders that impact the ocular tear film and integrity of the ocular surface including the cornea,conjunctiva,lacrimal glands,tear film and eyelids.As the main functions of the ocular surface are to maintain corneal transparency and hydration and protection of the corneal and conjunctival epithelium,the loss of ocular homeostasis leads to serious clinical manifestations.
基金supported by the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Officesupported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under Contract No. DE-SC0012704+1 种基金supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357supported by the Vehicle Technologies Office of the U.S. Department of Energy。
文摘Nickel-rich transition-metal oxides are widely regarded as promising cathode materials for high-energydensity lithium-ion batteries for emerging electric vehicles. However, achieving high energy density in Ni-rich cathodes is accompanied by substantial safety and cycle-life obstacles. The major issues of Ni-rich cathodes at high working potentials are originated from the unstable cathode-electrolyte interface, while the underlying mechanism of parasitic reactions towards surface reconstructions of cathode materials is not well understood. In this work, we controlled the Li_(2)CO_(3) impurity content on LiNi_(0.83)Mn_(0.1)Co_(0.07)O_(2) cathodes using air, tank-air, and O_(2) synthesis environments. Home-built high-precision leakage current and on-line electrochemical mass spectroscopy experiments verify that Li_(2)CO_(3) impurity is a significant promoter of parasitic reactions on Ni-rich cathodes. The rate of parasitic reactions is strongly correlated to Li_(2)CO_(3) content and severe performance deterioration of Ni83 cathodes.The post-mortem characterizations via high-resolution transition electron microscope and X-ray photoelectron spectroscopy depth profiles reveal that parasitic reactions promote more Ni reduction and O deficiency and even rock-salt phase transformation at the surface of cathode materials. Our observation suggests that surface reconstructions have a strong affiliation to parasitic reactions that create chemically acidic environment to etch away the lattice oxygen and offer the electrical charge to reduce the valence state of transition metal. Thus, this study advances our understanding on surface reconstructions of Nirich cathodes and prepares us for searching for rational strategies.
文摘A new method for solving the tiling problem of surface reconstruction is proposed. The proposed method uses a snake algorithm to segment the original images, the contours are then transformed into strings by Freeman＇ s code. Symbolic string matching technique is applied to establish a correspondence between the two consecutive contours. The surface is composed of the pieces reconstructed from the correspondence points. Experimental results show that the proposed method exhibits a good behavior for the quality of surface reconstruction and its time complexity is proportional to mn where m and n are the numbers of vertices of the two consecutive slices, respectively.
基金supported by the National Key Research&Development Program of China(No.2022YFB4004301)the National Natural Science Foundation of China(Nos.52201274 and 52307250)the Shaanxi Province key research and development plan,China(No.2024CY2-GJHX-53).
文摘TiFe alloys are AB-based hydrogen storage materials with unique characteristics and a wide range of applications.However,the presence of impurity gases(such as O_(2),CO,CO_(2),and CH4)has a considerable impact on the hydrogen storage capacity and kinetics of TiFe alloys,drastically limiting their practical application in hydrogen storage.Consequently,in this study,we investigated the hydrogen absorption kinetics and cycling performance of the TiFe_(0.9) alloy in the presence of common impurity gases(including CH4,CO,CO_(2),and O_(2))and determined the corresponding poisoning mechanisms.Specifically,we found that CH4 did not react with the alloy but acted through physical coverage.In contrast,CO and CO_(2) occupy the active sites for H_(2),significantly impeding the dissociation and absorption of H_(2).In addition,O_(2) reacts directly with the alloy to form a passivating layer that prevents hydrogen absorption.These findings were fur-ther corroborated by in situ Fourier transform infrared spectrometry(FTIR)and density functional theory(DFT).The relationship between the adsorption energies of the impurity gases and hydrogen obtained through DFT calculations complements the experimental results.Un-derstanding these poisoning behaviors is crucial for designing Ti-based high-entropy hydrogen storage alloy alloys with enhanced resist-ance to poisoning.
基金Project supported by the National Natural Science Foundation of China(Grant No.51102009)the Fundamental Research Funds for the Central Universities,China(Grant No.JD1109)
文摘The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the parallel and vertical channels, and the surface reconstructions of Sn（111） induced by oxygen adsorption are studied. Based on this, the adsorption behaviours of O2 on X（111） （X=Si, Ge, Sn, Pb） surfaces are analysed, and the most stable adsorption channels of O2 on X（111） （X=Si, Ge, Sn, Pb） are identified. The surface reconstructions and electron distributions along the most stable adsorption channels are discussed and compared. The results show that the O2 adsorption ability declines gradually and the amount of charge transferred decreases with the enhancement of metallicity.
基金Project supported by the National Natural Science Foundation of China(21971129,21961022,21661023)the Inner Mongolia Autonomous Region 2022 Leading Talent Team of Science and Technology(2022LJRC0008)+5 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022MS02014,2021BS02007)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(NJYT23031)the 111 Project(D20033)the"Grassland Leading Talent"Program of Inner Mongoliathe"Grassland-Talent"Innovation Team of Inner Mongoliathe"Science and Technology for A Better Development of Inner Mongolia"Program(2020XM03)。
文摘The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.
