Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the or...Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.展开更多
The reaction of triplet fusion,also named triplet-triplet annihilation,has attracted a lot of research interests because of its wide applications in photocatalytic,solar cells,and bioimaging.As for the singlet oxygen ...The reaction of triplet fusion,also named triplet-triplet annihilation,has attracted a lot of research interests because of its wide applications in photocatalytic,solar cells,and bioimaging.As for the singlet oxygen photosensitization,the reactive singlet oxygen species are generated through the energy transfers from photosensitizer(PS)to ground triplet oxygen molecule.In this work,we computed the electronic coupling for singlet oxygen photosensitization using the nonadiabatic coupling from the quantum chemical calculation.Then we utilized the molecular orbital(MO)overlaps to approximate it,where the MOs were computed from isolated single molecules.As demonstrated with quantitative results,this approach well describes the distribution of the coupling strength as the function of the intermolecular distance between the sensitizer and O_(2),providing us a simple but effective way to predict the coupling of triplet fusion reactions.展开更多
Engineering the electronic structure of surface active sites at the atomic level can be an efficient way to modulate the reactivity of catalysts.Herein,we report the rational tuning of surface electronic structure of ...Engineering the electronic structure of surface active sites at the atomic level can be an efficient way to modulate the reactivity of catalysts.Herein,we report the rational tuning of surface electronic structure of FePS_(3) nanosheets(NSs)by anchoring atomically dispersed metal atom.Theoretical calculations predict that the strong electronic coupling effect in single-atom Ni-FePS_(3) facilitates electron aggregation from Fe atom to the nearby Ni-S bond and enhances the electron-transfer of Ni and S sites,which balances the oxygen species adsorption capacity,reinforces water adsorption and dissociation process to accelerate corresponding oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).The optimal Ni-FePS_(3)NSs/C exhibits outstanding electrochemical water-splitting activities,delivering an overpotential of 287 mV at the current density of 10 mA cm^(-2) and a Tafel slope of 41.1 mV dec^(-1) for OER;as well as an overpotential decrease of 219 mV for HER compared with pure FePS_(3)NSs/C.The concept of electronic coupling interaction between the substrate and implanted single active species offers an additional method for catalyst design and beyond.展开更多
Interfacial electron transfer governs electrochemical heterogeneity at the single-entity level.Herein,we investigated the electronic coupling event during electrodissolution processes of single silver nanoentities on ...Interfacial electron transfer governs electrochemical heterogeneity at the single-entity level.Herein,we investigated the electronic coupling event during electrodissolution processes of single silver nanoentities on a Au electrode through a synchronized electrochemical-optical tracking platform.By implementing strategic control of interfacial gap distances and electrolyte composition,a marked differentiation of single-particle reaction dynamics can be achieved.The integration of superlocalization methodology reveals position-correlated optical centroid shifts during electrodissolution processes,demonstrating heterogeneous oxidation dynamics arising from spatially nonuniform surface oxide formation.Crucially,SAMmediated gap regulation enables the precise regulation of interfacial electric field enhancement.Our methodology resolves electronic coupling heterogeneity at subnanowire scale while proving molecular interlayer-dependent modulation of coupling lifetimes.This electrochemical-optical imaging strategy establishes nanoscale spatial mapping of electrochemical dynamics,quantitative correlation between interfacial structure and coupling efficiency,and real-time tracking of transient electronic states.These findings demonstrate the capability of advanced optical imaging methodologies in elucidating structure−activity relationships at nanoscale interfaces,providing mechanistic insights for single-entity electrochemistry and nanoscale energy conversion systems.展开更多
Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from...Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from unfavorable OH^(−)adsorption capability and low electrochemical activity of Fe sites,result in electrode kinetic delays for Fe anodes.Here,we report Mn and S co-modified FeOOH(MSFF)nanosheets as an advanced anode in Ni-Fe batteries,synthesized from a facile one-step surface-redox-etching method at room temperature.Based on the strong electronic coupling effect between Mn and S atoms,such MSFF anode presents fast electron transport capability,enhanced OH^(−)-adsorption capability,and redox reactivity.Specifically,the MSFF anode can achieve a high areal capacity of 2 mAh cm^(−2)at 10 mA cm^(−2),which retains a staggering 96%of the initial capacity after undergoing 9000 cycles at a higher current density of 30 mA cm^(−2).In addition,the assembled Ni-Fe battery can provide a capacity of 0.85 mAh cm^(−2)at 16 mA cm^(−2),significantly outperforming most recently reported aqueous rechargeable batteries.This work may offer an innovative and feasible approach for modulating the local electronic structure of high-performance Ni-Fe battery electrode materials.展开更多
The interstitial structure and weak Ni-N interaction of Ni3N lead to high unoccupied d orbital energy and unsuitable orbital orientation,which consequently results in weak orbital coupling with H2O and slow water diss...The interstitial structure and weak Ni-N interaction of Ni3N lead to high unoccupied d orbital energy and unsuitable orbital orientation,which consequently results in weak orbital coupling with H2O and slow water dissociation kinetics for alkaline hydrogen evolution catalysis.Herein,we successfully lower the unoccupied d orbital energy of Ni3N to strengthen the interfacial electronic coupling by employing the strong electron pulling capability of oxygen dopants.The prepared O-Ni3N catalyst delivers an overpotential of 55 mV at 10 mA cm−2,very close to the commercial Pt/C.Refined structural characterization indicates the oxygen incorporation can decrease the electron densities around the Ni sites.Moreover,density functional theory calculation further proves the oxygen incorporation can create more unoccupied orbitals with lower energy and superior orientation for water adsorption and dissociation.The concept of orbital-regulated interfacial electronic coupling could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond.展开更多
Bright emission of organic luminogens at aggregated state has attracted increasing attention for their potential applications in opto-electronic devices and bio-/chemo-sensors.In this article,upon the introduction of ...Bright emission of organic luminogens at aggregated state has attracted increasing attention for their potential applications in opto-electronic devices and bio-/chemo-sensors.In this article,upon the introduction of different substituents(Br,Ph and TPh)to the large conjugated core of 9-methyl-9H-dibenzo[a,c]carbazole(DBC)moiety,the resultant luminogens demonstrated PL quantum yields in solid state ranging from 4.81%to 47.39%.Through the systematic investigation of molecular packing,together with theory calculation,the strong intermolecular electronic coupling in the dimers is proved as the main factor to the bright emission in the solid state.The results afforded a new avenue to investigate the intrinsic relationship among the molecular structures,packing modes and emission properties.展开更多
Diruthenium ethynyl complexes 1--3 （1： 1,5-dithia-s-indacene-4,8-dione; 2： 4,8-diethoxybenzo[1,2-b：4,5- b＇]dithiophene; 3： 4,8-didodecyloxybenzo[1,2-b：4,5-b＇]dithiophene） have been synthesized by incorporatin...Diruthenium ethynyl complexes 1--3 （1： 1,5-dithia-s-indacene-4,8-dione; 2： 4,8-diethoxybenzo[1,2-b：4,5- b＇]dithiophene; 3： 4,8-didodecyloxybenzo[1,2-b：4,5-b＇]dithiophene） have been synthesized by incorporating the re- spective conjugated heterocyclic spacer and characterized by NMR and elemental analysis. The effects of bridge ligands＇ properties on electronic coupling between redox-active ruthenium terminal groups were investigated by electrochemistry, UV/vis/near-IR and IR spectroelectrochemistry combined with density functional theory （DFT） and time-dependent DFT calculations. Electrochemistry results indicated that complexes 1--3 exhibit two fully re- versible oxidation waves, and complexes 2 and 3 with electron-rich and π-conjuagted bridge ligands are character- ized by excellent electrochemical properties. Furthermore, the larger v（C≡C） separation from the IR spectroelec- trochemical results of 2 and 3 and the intense NIR absorption features of singly oxidized species 2＋ and 3＋ re- vealed that their molecular skeletons have superior abilities to delocalize the positive charge. The spin density dis- tribution from DFT calculations proved the conclusions of this study.展开更多
With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,
High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the...High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.展开更多
Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to ac...Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to achieve high efficiency. Molecular light absorbers offer flexibility in fine tuning of orbital energetics,and metal oxide nanoparticles have emerged as robust oxygen evolving catalysts. Hence, these material choices offer a promising approach for the development of photocatalytic systems for water oxidation.However, efficient charge transfer coupling of molecular light absorbers and metal oxide nanoparticle catalysts has proven a challenge. Recent new approaches toward the efficient coupling of these components based on synthetic design improvements combined with direct spectroscopic observation and kinetic evaluation of charge transfer processes are discussed.展开更多
The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stab...The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.展开更多
Ionic thermoelectrics(i-TE) possesses great potential in powering distributed electronics because it can generate thermopower up to tens of millivolts per Kelvin. However,as ions cannot enter external circuit, the uti...Ionic thermoelectrics(i-TE) possesses great potential in powering distributed electronics because it can generate thermopower up to tens of millivolts per Kelvin. However,as ions cannot enter external circuit, the utilization of i-TE is currently based on capacitive charge/discharge, which results in discontinuous working mode and low energy density. Here,we introduce an ion–electron thermoelectric synergistic(IETS)effect by utilizing an ion–electron conductor. Electrons/holes can drift under the electric field generated by thermodiffusion of ions, thus converting the ionic current into electrical current that can pass through the external circuit. Due to the IETS effect, i-TE is able to operate continuously for over 3000 min.Moreover, our i-TE exhibits a thermopower of 32.7 mV K^(-1) and an energy density of 553.9 J m^(-2), which is more than 6.9 times of the highest reported value. Consequently, direct powering of electronics is achieved with i-TE. This work provides a novel strategy for the design of high-performance i-TE materials.展开更多
Super-high resolution laser-based angle-resolved photoemission measurements are carried out on LiFeAs superconductor to investigate its electron dynamics. Three energy scales at ~ 20 meV, ~ 34 meV, and ~ 55 meV are re...Super-high resolution laser-based angle-resolved photoemission measurements are carried out on LiFeAs superconductor to investigate its electron dynamics. Three energy scales at ~ 20 meV, ~ 34 meV, and ~ 55 meV are revealed for the first time in the electron self-energy both in the superconducting state and normal state. The ~ 20 meV and ~ 34 meV scales can be attributed to the coupling of electrons with sharp bosonic modes which are most likely phonons. These observations provide definitive evidence on the existence of mode coupling in iron-based superconductors.展开更多
We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm（A-B） interferometer. By using the Keldysh non-equilibrium Gree...We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm（A-B） interferometer. By using the Keldysh non-equilibrium Green＇s function technique, the photon-assisted spin-dependent average current is analyzed. The T-shaped three-quantum-dot molecule A-B interferometer exhibits excellent controllability in the average current resonance spectra by adjusting the interdot coupling strength, Rashba spin-orbit coupling strength, magnetic flux, and amplitude of the time-dependent external field.Efficient spin filtering and multiple electron-photon pump functions are exploited in the multi-quantum-dot molecule A-B interferometer by a time-modulated external field.展开更多
The development of cost-effective,highly efficient,and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction(HER).Herein,a simplified synthesis protocol was designed to ac...The development of cost-effective,highly efficient,and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction(HER).Herein,a simplified synthesis protocol was designed to achieve a self-standing electrode,composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters(ACP/Ru_(SAC+C))via acid activation,immersion,and high-temperature pyrolysis.Ab initio molecular dynamics(AIMD)calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper.Furthermore,the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy(AC-STEM),X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy(XAS).Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect,tuning the electronic structure and thereby significantly enhancing their catalytic performance.Notably,the ACP/Ru_(SAC+C)exhibits a remarkable turnover frequency(TOF)of 18 s^(−1)and an exceptional mass activity(MA)of 2.2 A mg^(−1),surpassing the performance of conventional Pt electrodes.The self-standing electrode,featuring harmoniously coexisting Ru states,stands out as a prospective choice for advancing HER catalysts,enhancing energy efficiency,productivity,and selectivity.展开更多
Supercapacitor has been widely known as a representative electrochemical energy storage device with high power density and long lifespan.Recently,with the deeper understanding of its charge storage mechanism,unidirect...Supercapacitor has been widely known as a representative electrochemical energy storage device with high power density and long lifespan.Recently,with the deeper understanding of its charge storage mechanism,unidirectional-charging supercapacitor,also called supercapacitor diode(CAPode),is successfully developed based on the ion-sieving effect of its working electrode towards electrolyte ions.Because CAPode integrates mobile ion and mobile electron in one hybrid circuit,it has a great potential in the emerging fields of ion/electron coupling logic operations,human–machine interface,neural network interaction,and in vivo diagnosis and treatment.Accordingly,we herein elucidate the working mechanism and design philosophy of CAPode,and summarize the electrode materials that are suitable for constructing CAPode.Meanwhile,some other supercapacitor-based devices beyond CAPode are also introduced,and their potential applications are instructively presented.Finally,we outline the challenges and chances of CAPode-related techniques.展开更多
In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the ...In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the mechanism is still under debate.Here,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and spectroscopy.The temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer model.The ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the QCP.The lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.展开更多
High-performance infrared emitters hold substantial importance in modern engineering and physics.Here,we introduce graphene/PZT(lead zirconate titanate)heterostructure as a new platform for the development of infrared...High-performance infrared emitters hold substantial importance in modern engineering and physics.Here,we introduce graphene/PZT(lead zirconate titanate)heterostructure as a new platform for the development of infrared source structure based on an electron-phonon coupling and emitting mechanism.A series of electrical characterizations including carrier mobility[11,361.55 cm^(2)/(V.s)],pulse current(30 ms response time),and cycling stability(2000 cycles)modulated by polarized film was provided.展开更多
First-row transition metal compounds have been widely explored as oxygen evolution reaction(OER)electrocatalysts due to their impressive performance in this application.However,the activity trends of these electrocata...First-row transition metal compounds have been widely explored as oxygen evolution reaction(OER)electrocatalysts due to their impressive performance in this application.However,the activity trends of these electrocatalysts remain elusive due to the effect of inevitable iron impurities in alkaline electrolytes on the OER;the inhomogeneous structure of iron-based(oxy)hydroxides further complicates this situation.Bimetallic metal-organic frameworks(MOFs)have the advantages of well-defined and uniform atomic structures and the tunable coordination environments,allowing the structure-activity relationships of bimetallic sites to be precisely explored.Therefore,we prepared a series of iron-based bimetallic MOFs(denoted as Fe_(2)M-MIL-88B,M=Mn,Co,or Ni)and systematically compared their electrocatalytic performance in the OER in this work.All the bimetallic MOFs exhibited higher OER activity than their monometallic iron-based counterpart,with their activity following the order FeNi>FeCo>FeMn.In an alkaline electrolyte,Fe2Ni-MIL-88B showed the lowest overpotential to achieve a current density of 10 mA cm^(–2)(307 mV)and the smallest Tafel slope(38 mV dec^(–1)).The experimental and calculated results demonstrated that iron and nickel exhibited the strongest coupling effect in the series,leading to modification of the electronic structure,which is crucial for tuning the electrocatalytic activity.展开更多
基金The authors appreciate the supports from the National Research Foundation(NRF),Prime Minister’s Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)programme.We also acknowledge financial support from the academic research fund AcRF tier 2(M4020246,ARC10/15),Ministry of Education,Singapore.
文摘Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.
基金the supports from the Chinese Academy of Sciences(CAS)Institute of Chemistry,CAS+3 种基金the supports from the National Natural Science Foundation of China(No.21933011)the Beijing Municipal Science&Technology Commission(No.Z191100007219009)the K.C.Wong Education Foundationthe support from the National Natural Science Foundation of China(No.21773073)。
文摘The reaction of triplet fusion,also named triplet-triplet annihilation,has attracted a lot of research interests because of its wide applications in photocatalytic,solar cells,and bioimaging.As for the singlet oxygen photosensitization,the reactive singlet oxygen species are generated through the energy transfers from photosensitizer(PS)to ground triplet oxygen molecule.In this work,we computed the electronic coupling for singlet oxygen photosensitization using the nonadiabatic coupling from the quantum chemical calculation.Then we utilized the molecular orbital(MO)overlaps to approximate it,where the MOs were computed from isolated single molecules.As demonstrated with quantitative results,this approach well describes the distribution of the coupling strength as the function of the intermolecular distance between the sensitizer and O_(2),providing us a simple but effective way to predict the coupling of triplet fusion reactions.
基金the National Natural Science Foundation of China(12025503,U1867215,11875211,U1932134)Hubei Provincial Natural Science Foundation(2019CFA036)the Fundamental Research Funds for the Central Universities(2042020kf0211)。
文摘Engineering the electronic structure of surface active sites at the atomic level can be an efficient way to modulate the reactivity of catalysts.Herein,we report the rational tuning of surface electronic structure of FePS_(3) nanosheets(NSs)by anchoring atomically dispersed metal atom.Theoretical calculations predict that the strong electronic coupling effect in single-atom Ni-FePS_(3) facilitates electron aggregation from Fe atom to the nearby Ni-S bond and enhances the electron-transfer of Ni and S sites,which balances the oxygen species adsorption capacity,reinforces water adsorption and dissociation process to accelerate corresponding oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).The optimal Ni-FePS_(3)NSs/C exhibits outstanding electrochemical water-splitting activities,delivering an overpotential of 287 mV at the current density of 10 mA cm^(-2) and a Tafel slope of 41.1 mV dec^(-1) for OER;as well as an overpotential decrease of 219 mV for HER compared with pure FePS_(3)NSs/C.The concept of electronic coupling interaction between the substrate and implanted single active species offers an additional method for catalyst design and beyond.
基金National Natural Science Foundation of China(NSFC,Grant Number:22222406,22174062).
文摘Interfacial electron transfer governs electrochemical heterogeneity at the single-entity level.Herein,we investigated the electronic coupling event during electrodissolution processes of single silver nanoentities on a Au electrode through a synchronized electrochemical-optical tracking platform.By implementing strategic control of interfacial gap distances and electrolyte composition,a marked differentiation of single-particle reaction dynamics can be achieved.The integration of superlocalization methodology reveals position-correlated optical centroid shifts during electrodissolution processes,demonstrating heterogeneous oxidation dynamics arising from spatially nonuniform surface oxide formation.Crucially,SAMmediated gap regulation enables the precise regulation of interfacial electric field enhancement.Our methodology resolves electronic coupling heterogeneity at subnanowire scale while proving molecular interlayer-dependent modulation of coupling lifetimes.This electrochemical-optical imaging strategy establishes nanoscale spatial mapping of electrochemical dynamics,quantitative correlation between interfacial structure and coupling efficiency,and real-time tracking of transient electronic states.These findings demonstrate the capability of advanced optical imaging methodologies in elucidating structure−activity relationships at nanoscale interfaces,providing mechanistic insights for single-entity electrochemistry and nanoscale energy conversion systems.
基金financially supported by National Natural Science Foundation of China(Nos.52407242,52162025)Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202123).
文摘Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from unfavorable OH^(−)adsorption capability and low electrochemical activity of Fe sites,result in electrode kinetic delays for Fe anodes.Here,we report Mn and S co-modified FeOOH(MSFF)nanosheets as an advanced anode in Ni-Fe batteries,synthesized from a facile one-step surface-redox-etching method at room temperature.Based on the strong electronic coupling effect between Mn and S atoms,such MSFF anode presents fast electron transport capability,enhanced OH^(−)-adsorption capability,and redox reactivity.Specifically,the MSFF anode can achieve a high areal capacity of 2 mAh cm^(−2)at 10 mA cm^(−2),which retains a staggering 96%of the initial capacity after undergoing 9000 cycles at a higher current density of 30 mA cm^(−2).In addition,the assembled Ni-Fe battery can provide a capacity of 0.85 mAh cm^(−2)at 16 mA cm^(−2),significantly outperforming most recently reported aqueous rechargeable batteries.This work may offer an innovative and feasible approach for modulating the local electronic structure of high-performance Ni-Fe battery electrode materials.
基金This work was supported by the National Natural Science Foundation of China(21771169,51801075,11722543)the National Key Research and Development Program of China(2017YFA0206703)+1 种基金Anhui Provincial Natural Science Foundation(BJ2060190077)Recruitment Program of Global Expert,and the Fundamental Research Funds for the Central Universities(WK2060190074,WK2060190081,WK2310000066).
文摘The interstitial structure and weak Ni-N interaction of Ni3N lead to high unoccupied d orbital energy and unsuitable orbital orientation,which consequently results in weak orbital coupling with H2O and slow water dissociation kinetics for alkaline hydrogen evolution catalysis.Herein,we successfully lower the unoccupied d orbital energy of Ni3N to strengthen the interfacial electronic coupling by employing the strong electron pulling capability of oxygen dopants.The prepared O-Ni3N catalyst delivers an overpotential of 55 mV at 10 mA cm−2,very close to the commercial Pt/C.Refined structural characterization indicates the oxygen incorporation can decrease the electron densities around the Ni sites.Moreover,density functional theory calculation further proves the oxygen incorporation can create more unoccupied orbitals with lower energy and superior orientation for water adsorption and dissociation.The concept of orbital-regulated interfacial electronic coupling could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond.
基金supported by the National Natural Science Foundation of China(51673151,51973162,21875174,21734007)the Natural Science Foundation of Hubei Province(2017CFA002)。
文摘Bright emission of organic luminogens at aggregated state has attracted increasing attention for their potential applications in opto-electronic devices and bio-/chemo-sensors.In this article,upon the introduction of different substituents(Br,Ph and TPh)to the large conjugated core of 9-methyl-9H-dibenzo[a,c]carbazole(DBC)moiety,the resultant luminogens demonstrated PL quantum yields in solid state ranging from 4.81%to 47.39%.Through the systematic investigation of molecular packing,together with theory calculation,the strong intermolecular electronic coupling in the dimers is proved as the main factor to the bright emission in the solid state.The results afforded a new avenue to investigate the intrinsic relationship among the molecular structures,packing modes and emission properties.
基金The authors acknowledge financial support from Na- tional Natural Science Foundation of China （No. 21602049） and the Natural Science Foundation of Hu- nan Province, China （No. 2017JJ3004）.
文摘Diruthenium ethynyl complexes 1--3 （1： 1,5-dithia-s-indacene-4,8-dione; 2： 4,8-diethoxybenzo[1,2-b：4,5- b＇]dithiophene; 3： 4,8-didodecyloxybenzo[1,2-b：4,5-b＇]dithiophene） have been synthesized by incorporating the re- spective conjugated heterocyclic spacer and characterized by NMR and elemental analysis. The effects of bridge ligands＇ properties on electronic coupling between redox-active ruthenium terminal groups were investigated by electrochemistry, UV/vis/near-IR and IR spectroelectrochemistry combined with density functional theory （DFT） and time-dependent DFT calculations. Electrochemistry results indicated that complexes 1--3 exhibit two fully re- versible oxidation waves, and complexes 2 and 3 with electron-rich and π-conjuagted bridge ligands are character- ized by excellent electrochemical properties. Furthermore, the larger v（C≡C） separation from the IR spectroelec- trochemical results of 2 and 3 and the intense NIR absorption features of singly oxidized species 2＋ and 3＋ re- vealed that their molecular skeletons have superior abilities to delocalize the positive charge. The spin density dis- tribution from DFT calculations proved the conclusions of this study.
文摘With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,
文摘High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.
基金supported by the Director,Office of Science,Office of Basic Energy Sciences,Division of Chemical,Geological and Biosciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231
文摘Water oxidation, as a mandatory reaction of solar fuels conversion systems, requires the use of light absorbers with electronic properties that are well matched with those of the multi-electron catalyst in order to achieve high efficiency. Molecular light absorbers offer flexibility in fine tuning of orbital energetics,and metal oxide nanoparticles have emerged as robust oxygen evolving catalysts. Hence, these material choices offer a promising approach for the development of photocatalytic systems for water oxidation.However, efficient charge transfer coupling of molecular light absorbers and metal oxide nanoparticle catalysts has proven a challenge. Recent new approaches toward the efficient coupling of these components based on synthetic design improvements combined with direct spectroscopic observation and kinetic evaluation of charge transfer processes are discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.12122405,12274169,and 11574109)the Fundamental Research Funds for the Central Universities。
文摘The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.
基金financially supported by research grants from the Natural Science Foundation of China [Grant No. 62074022 (K.S.), 12004057 (Y.J.Z.), 52173235 (M.L.)]the Natural Science Foundation of Chongqing [cstc2021jcyj-jqX0015 (K.S.)]+3 种基金Chongqing Talent Plan [cstc2021ycjh-bgzxm0334 (S.S.C.), CQYC2021059206 (K.S.)]Fundamental Research Funds for the Central Universities [No. 2020CDJQY-A055 (K.S.)]the Key Laboratory of Low-grade Energy Utilization Technologies and Systems [Grant No. LLEUTS-201901 (K.S.)]support from Chongqing Postgraduate Research and Innovation Project (CYS22032)。
文摘Ionic thermoelectrics(i-TE) possesses great potential in powering distributed electronics because it can generate thermopower up to tens of millivolts per Kelvin. However,as ions cannot enter external circuit, the utilization of i-TE is currently based on capacitive charge/discharge, which results in discontinuous working mode and low energy density. Here,we introduce an ion–electron thermoelectric synergistic(IETS)effect by utilizing an ion–electron conductor. Electrons/holes can drift under the electric field generated by thermodiffusion of ions, thus converting the ionic current into electrical current that can pass through the external circuit. Due to the IETS effect, i-TE is able to operate continuously for over 3000 min.Moreover, our i-TE exhibits a thermopower of 32.7 mV K^(-1) and an energy density of 553.9 J m^(-2), which is more than 6.9 times of the highest reported value. Consequently, direct powering of electronics is achieved with i-TE. This work provides a novel strategy for the design of high-performance i-TE materials.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0300300,2016YFA0300600,2017YFA0302900,2018YFA0704200,2018YFA0305600,and 2019YFA0308000)the National Natural Science Foundation of China(Grant Nos.11888101,11922414,and 11874405)+2 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB25000000 and XDB33010300)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2017013)the Research Program of Beijing Academy of Quantum Information Sciences(Grant No.Y18G06)。
文摘Super-high resolution laser-based angle-resolved photoemission measurements are carried out on LiFeAs superconductor to investigate its electron dynamics. Three energy scales at ~ 20 meV, ~ 34 meV, and ~ 55 meV are revealed for the first time in the electron self-energy both in the superconducting state and normal state. The ~ 20 meV and ~ 34 meV scales can be attributed to the coupling of electrons with sharp bosonic modes which are most likely phonons. These observations provide definitive evidence on the existence of mode coupling in iron-based superconductors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11447132 and 11504042)the Natural Science Foundation of Heilongjiang,China(Grant No.A201405)+2 种基金111 Project to Harbin Engineering University,China(Grant No.B13015)Chongqing Science and Technology Commission Project,China(Grant Nos.cstc2014jcyj A00032 and cstc2016jcyj A1158)Scientific Research Project for Advanced Talents of Yangtze Normal University,China(Grant No.2017KYQD09)
文摘We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm（A-B） interferometer. By using the Keldysh non-equilibrium Green＇s function technique, the photon-assisted spin-dependent average current is analyzed. The T-shaped three-quantum-dot molecule A-B interferometer exhibits excellent controllability in the average current resonance spectra by adjusting the interdot coupling strength, Rashba spin-orbit coupling strength, magnetic flux, and amplitude of the time-dependent external field.Efficient spin filtering and multiple electron-photon pump functions are exploited in the multi-quantum-dot molecule A-B interferometer by a time-modulated external field.
基金supported by the National Research Foundation of Korea(NRF),funded by the Korean government(2022M3H4A1A01012712,2022M3H4A1A04096380)S.Back acknowledges the support from the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2016R1A6A1A03012845)and generous supercomputing time from KISTI.
文摘The development of cost-effective,highly efficient,and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction(HER).Herein,a simplified synthesis protocol was designed to achieve a self-standing electrode,composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters(ACP/Ru_(SAC+C))via acid activation,immersion,and high-temperature pyrolysis.Ab initio molecular dynamics(AIMD)calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper.Furthermore,the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy(AC-STEM),X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy(XAS).Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect,tuning the electronic structure and thereby significantly enhancing their catalytic performance.Notably,the ACP/Ru_(SAC+C)exhibits a remarkable turnover frequency(TOF)of 18 s^(−1)and an exceptional mass activity(MA)of 2.2 A mg^(−1),surpassing the performance of conventional Pt electrodes.The self-standing electrode,featuring harmoniously coexisting Ru states,stands out as a prospective choice for advancing HER catalysts,enhancing energy efficiency,productivity,and selectivity.
基金We acknowledge the financial support from the China Postdoctoral Science Foundation(Grant Nos.BX20220139 and 2021M701530)the National Natural Science Foundation of China(Grant No.61874166)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-sp50)the Science and Technology Program of Qinghai Province(Grant No.2022-ZJ-703).
文摘Supercapacitor has been widely known as a representative electrochemical energy storage device with high power density and long lifespan.Recently,with the deeper understanding of its charge storage mechanism,unidirectional-charging supercapacitor,also called supercapacitor diode(CAPode),is successfully developed based on the ion-sieving effect of its working electrode towards electrolyte ions.Because CAPode integrates mobile ion and mobile electron in one hybrid circuit,it has a great potential in the emerging fields of ion/electron coupling logic operations,human–machine interface,neural network interaction,and in vivo diagnosis and treatment.Accordingly,we herein elucidate the working mechanism and design philosophy of CAPode,and summarize the electrode materials that are suitable for constructing CAPode.Meanwhile,some other supercapacitor-based devices beyond CAPode are also introduced,and their potential applications are instructively presented.Finally,we outline the challenges and chances of CAPode-related techniques.
基金Project supported by the National Key R&D Program of China (Grant Nos. 2022YFA1403203, 2022YFA1403400, and 2021YFA1400400)the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302802)+2 种基金the National Natural Science Foundation of China (Grant Nos. 12074002, 12104004, 12204008, and 12374133)the Chinese Academy of Sciences (Grant Nos. XDB33000000 and GJTD-2020-01)the Major Basic Program of Natural Science Foundation of Shandong Province (Grant No. ZR2021ZD01)。
文摘In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the mechanism is still under debate.Here,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and spectroscopy.The temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer model.The ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the QCP.The lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.
基金Natural Science Foundation of Shanxi Province(20210302123056)Shanxi Provincial Key Research and Development Project(202102040201007,202203021223005)National Natural Science Foundation of China(52275577,52205609).
文摘High-performance infrared emitters hold substantial importance in modern engineering and physics.Here,we introduce graphene/PZT(lead zirconate titanate)heterostructure as a new platform for the development of infrared source structure based on an electron-phonon coupling and emitting mechanism.A series of electrical characterizations including carrier mobility[11,361.55 cm^(2)/(V.s)],pulse current(30 ms response time),and cycling stability(2000 cycles)modulated by polarized film was provided.
文摘First-row transition metal compounds have been widely explored as oxygen evolution reaction(OER)electrocatalysts due to their impressive performance in this application.However,the activity trends of these electrocatalysts remain elusive due to the effect of inevitable iron impurities in alkaline electrolytes on the OER;the inhomogeneous structure of iron-based(oxy)hydroxides further complicates this situation.Bimetallic metal-organic frameworks(MOFs)have the advantages of well-defined and uniform atomic structures and the tunable coordination environments,allowing the structure-activity relationships of bimetallic sites to be precisely explored.Therefore,we prepared a series of iron-based bimetallic MOFs(denoted as Fe_(2)M-MIL-88B,M=Mn,Co,or Ni)and systematically compared their electrocatalytic performance in the OER in this work.All the bimetallic MOFs exhibited higher OER activity than their monometallic iron-based counterpart,with their activity following the order FeNi>FeCo>FeMn.In an alkaline electrolyte,Fe2Ni-MIL-88B showed the lowest overpotential to achieve a current density of 10 mA cm^(–2)(307 mV)and the smallest Tafel slope(38 mV dec^(–1)).The experimental and calculated results demonstrated that iron and nickel exhibited the strongest coupling effect in the series,leading to modification of the electronic structure,which is crucial for tuning the electrocatalytic activity.
