Previous studies have demonstrated that increasing Fe doping content can enhance the saturation magnetization and maximum energy product of 2:17-type Sm-Co rare-earth permanent magnets.Howeve r,syste matic theo retica...Previous studies have demonstrated that increasing Fe doping content can enhance the saturation magnetization and maximum energy product of 2:17-type Sm-Co rare-earth permanent magnets.Howeve r,syste matic theo retical calculations and the effects of other transition metal dopants have yet to be explored.This study employed first-principles computational methods to investigate the effects of doping with 3d and Zr transition metal elements on the structural stability,magnetic properties,and electronic structure of Sm_(2)Co_(17)permanent magnets.The results indicate that Sc and Zr tend to occupy the Sm-6c site,while Ni,Cu and Zn preferentially occupy the 18h site,and Ti,V,Cr,Mn and Fe primarily occupy the Co-6c site.Except for V and Cu,all other elements effectively improve the structural stability of the doped systems.Additionally,Mn and Fe doping can significantly enhance the total magnetic moment and magnetocrystalline anisotropy energies of the Sm_(2)Co_(17)system,while Cr only increases the total magnetic moment.More importantly,doping with Cr,Mn and Fe within the doping co ntent range of9.8 at%<x<35.29 at% can simultaneously improve the structural stability,total magnetic moment and magnetocrystalline anisotropy energy of the Sm_(2)Co_(17) system.Our study provides valuable theoretical guidance for experimental exploration and is expected to promote the development and application of novel rare-earth permanent magnetic materials.展开更多
The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is fou...The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures,and the capacity decay during repeated charge-discharge cycles and the self-discharge are both suppressed, while the rate capability decreases.The alloy containing zirconium exhibits a longer cycle life and a better rate capability,but a much lower discharge capacity.The addition of titanium improves the rate capability, but the capacity decreases greatly.An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti,which improves the discharge-rate characteristics,and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.展开更多
A systematical investigation was carried out on structure and magnetic properties in SmFe_(9-x)V_(x)(x=0.4,0.8,1.2)compounds prepared by a single-roller quenching method.The high cool-down rate leads to metastable TbC...A systematical investigation was carried out on structure and magnetic properties in SmFe_(9-x)V_(x)(x=0.4,0.8,1.2)compounds prepared by a single-roller quenching method.The high cool-down rate leads to metastable TbCu_(7) phase in the parent compound,which gradually transforms into equilibrium ThMn_(12) structure with V-doping content increasing.The Curie temperature increases from 470 to 590 K with V doping,which is consistent with the phase transformation.Surprisingly,simultaneous increase in both coercivity and remanence is resulted by V doping,reaching the highest value of 685 kA·m^(-1)and 44.8×10^(-3)A·m^(2)·g^(-1)in x=1.2 compound,respectively.This phenomenon can be explained by the combination of phase transformation and intergranular exchange coupling throughδM-H plots.展开更多
Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzit...Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.展开更多
P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirabl...P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirable electrochemical performances by inducing anion/cation ions,changing morphology,adjusting valence,etc.In this work,several same-period elements of Sc,Ti,V,Cr,Fe,Cu and Zn are doped into Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)O_(2)cathodes,which are manipulated by ions radii and valence state,further studied by operando X-ray powder diffraction patterns(XRD).As a result,the Cu^(2+)doped cathode performed higher rate capacities(as high as 86 mAh/g even at 10 C)and more stable structures(capacity retention of~89.4%for 100 cycles),which owing to the synergistic effect among the tightened TMO_(2)layer,enlarged d-spacing,reduce O-O electrostatic repulsion,ameliorate lattice distortion as well as mitigate ordering of Na^(+)/vacancy.展开更多
We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alka...We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.展开更多
The restacking and oxidizable nature of vanadium-based carbon/nitride(V_(2)C-MXene)poses a significant challenge.Herein,tellurium(Te)-doped V_(2)C/V_(2)O_(3) electrocatalyst is constructed via mild H_(2)O_(2) oxidatio...The restacking and oxidizable nature of vanadium-based carbon/nitride(V_(2)C-MXene)poses a significant challenge.Herein,tellurium(Te)-doped V_(2)C/V_(2)O_(3) electrocatalyst is constructed via mild H_(2)O_(2) oxidation and calcination treatments.Especially,this work rationally exploits the inherent easy oxidation characteristic associated with MXene to alter the interfacial information,thereby obtaining stable self-generated vanadium-based heterointerfaces.Meanwhile,the microetching effect of H_(2)O_(2) creates numerous pores to address the restacking issues.Besides,Te element doping settles the issue of awkward levels of absorption/desorption ability of intermediates.The electrocatalyst obtains an unparalleled hydrogen evolution reaction and oxygen evolution reaction with the overpotential of 83.5 and 279.8 mV at−10 and 10 mA cm^(−2),respectively.In addition,the overall water-splitting device demonstrates a low cell voltage of 1.41 V to obtain 10 mA cm^(−2).Overall,the inherent drawbacks of MXene can be turned into benefits based on the planning strategy to create these electrocatalysts with desirable reaction kinetics.展开更多
Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-p...Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.展开更多
Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-...Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-doped LLZO(LLZGO),which exhibits high ionic conductivity.However,the limited size of the Liþtransport bottleneck restricts its high-current discharging performance.The present study focuses on the synthesis of Ga^(3+)þand Ba^(2+)þco-doped LLZO(LLZGBO)and investigates the influence of doping contents on the morphology,crystal structure,Liþtransport bottleneck size,and ionic conductivity.In particular,Ga_(0.32)Ba_(0.15)exhibits the highest ionic conductivity(6.11E-2 S cm^(-1) at 550 C)in comparison with other compositions,which can be attributed to its higher-energy morphology,larger bottleneck and unique Liþtransport channel.In addition to Ba^(2+),Sr^(2+)þand Ca^(2+)have been co-doped with Ga3þinto LLZO,respectively,to study the effect of doping ion radius on crystal structures and the properties of electrolytes.The characterization results demonstrate that the easier Liþtransport and higher ionic conductivity can be obtained when the electrolyte is doped with larger-radius ions.As a result,the assembled thermal battery with Ga_(0.32)Ba_(0.15)-LLZO electrolyte exhibits a remarkable voltage platform of 1.81 V and a high specific capacity of 455.65 mA h g^(-1) at an elevated temperature of 525℃.The discharge specific capacity of the thermal cell at 500 mA amounts to 63%of that at 100 mA,showcasing exceptional high-current discharging performance.When assembled as prototypes with fourteen single cells connected in series,the thermal batteries deliver an activation time of 38 ms and a discharge time of 32 s with the current density of 100 mA cm^(-2).These findings suggest that Ga,Ba co-doped LLZO solid-state electrolytes with high ionic conductivities holds great potential for high-capacity,quick-initiating and high-current discharging thermal batteries.展开更多
Sodium-ion batteries have emerged as promising candidates for next-generation large-scale energy storage systems due to the abundance of sodium resources,low solvation energy,and cost-effectiveness.Among the available...Sodium-ion batteries have emerged as promising candidates for next-generation large-scale energy storage systems due to the abundance of sodium resources,low solvation energy,and cost-effectiveness.Among the available cathode materials,vanadium-based sodium phosphate cathodes are particularly notable for their high operating voltage,excellent thermal stability,and superior cycling performance.However,these materials face significant challenges,including sluggish reaction kinetics,the toxicity of vanadium,and poor electronic conductivity.To overcome these limitations and enhance electrochemical performance,various strategies have been explored.These include morphology regulation via diverse synthesis routes and electronic structure optimization through metal doping,which effectively improve the diffusion of Na+and electrons in vanadium-based phosphate cathodes.This review provides a comprehensive overview of the challenges associated with V-based polyanion cathodes and examines the role of morphology and electronic structure design in enhancing performance.Key vanadium-based phosphate frameworks,such as orthophosphates(Na_(3)V_(2)(PO_(4))_(3)),pyrophosphates(NaVP_(2)O_(7),Na_(2)(VO)P_(2)O_(7),Na_(7)V_(3)(P_(2)O_(7))_(4)),and mixed phosphates(Na_(7)V_(4)(P_(2)O_(7))_(4)PO_(4)),are discussed in detail,highlighting recent advances and insights into their structure-property relationships.The design of cathode material morphology offers an effective approach to optimizing material structures,compositions,porosity,and ion/electron diffusion pathways.Simultaneously,electronic structure tuning through element doping allows for the regulation of band structures,electron distribution,diffusion barriers,and the intrinsic conductivity of phosphate compounds.Addressing the challenges associated with vanadium-based sodium phosphate cathode materials,this study proposes feasible solutions and outlines future research directions toward advancement of high-performance vanadium-based polyanion cathodes.展开更多
Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At eleva...Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At elevated temperatures,a spin-reorientation transition induces a ferrimagnetic state(FIM1)with in-plane magnetic moments,accompanied by a nonmonotonic Hall response that differs markedly from the low-temperature behavior.Upon indium doping,the long-range ferrimagnetic transition is progressively suppressed to lower temperatures,along with a noticeable reduction in magnetic anisotropy.Interestingly,at a doping level of x=1.2,the FIM1 state observed in the parent compound is completely eliminated.These systematic changes in magnetic ordering and transport properties underscore a coherent evolution of the electronic and magnetic states with doping,offering critical insights into the interplay among lattice structure,magnetism,and electronic behavior in kagome lattices.展开更多
Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligan...Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink.展开更多
Ni-Mn-Ti Heusler alloys have great potential for elastocaloric refrigeration due to the colossal caloric effect and good mechanical properties. However, theoretical calculations on the characterization of the elastoca...Ni-Mn-Ti Heusler alloys have great potential for elastocaloric refrigeration due to the colossal caloric effect and good mechanical properties. However, theoretical calculations on the characterization of the elastocaloric effect are rare. An important parameter to evaluate the elastocaloric effect is the transformation entropy change, whose main source is the vibrational entropy change (ΔS_(vib)). Unfortunately, the widely used quasiharmonic approximation method fails in the prediction of the vibrational entropy for high-temperature austenite due to its dynamical instability at 0 K. To solve this problem, the temperature dependent effective potential method was used considering the temperature and anharmonic effect. Sc, V, and Zr doping at the Ti sites in B2 disordered Ni_(8)Mn_(5)Ti_(3) were studied about phase stability, martensitic transformation, and elastocaloric properties. The results revealed the austenitic structures of all the doping systems exhibit antiferromagnetic coupling characteristics at 300 K due to the temperature effect. Sc and Zr doping at the Ti sites decreased the ΔS_(vib) value, whereas V doping at the Ti site increased the ΔS_(vib) value. Further analysis proved the important evaluation criterion that the ΔS_(vib) value increases with the tetragonal distortion ratio and volume change, which has important guiding significance for improving the elastocaloric effect. Besides, the calculations of elastic constants presented all the doping systems maintain outstanding ductility evaluated from the B/G ratio. This work provides an effective strategy for designing excellent elastocaloric material with large vibrational entropy change and good mechanical properties.展开更多
In this study,a novel class of niobium(Nb) doped titanate nanoflakes(TNFs) are fabricated through a onestep hydrothermal method.Nb doping affects the curving of titanate nanosheet,leading to the formation of nanoflake...In this study,a novel class of niobium(Nb) doped titanate nanoflakes(TNFs) are fabricated through a onestep hydrothermal method.Nb doping affects the curving of titanate nanosheet,leading to the formation of nanoflake structure.In addition,Nb5+ filled in the interlayers of [TiO6] alters the light adsorption property of pristine titanate.The band gap of Nb-TNFs is narrowed to 2.85 eV,while neat titanate nano tubes(TNTs) is 3.4 eV.The enhanced visible light adsorption significantly enhances the visible-lightdriven activity of Nb-TNFs for ibuprofen(IBP) degradation.The pseudo-first order kinetics constant for Nb-TNFs is calculated to be 1.04 h^-1,while no obvious removal is observed for TNTs.Photo-generated holes(h^+) and hydroxyl radicals(·OH) are responsible for IBP degradation.The photocatalytic activity of Nb-TNFs depends on pH condition,and the optimal pH value is found to be 5.In addition,Nb-TNFs exhibited superior photo-stability during the reuse cycles.The results demonstrated Nb-TNFs are very promising in photocatalytic water purification.展开更多
In this work,a non-toxic and environmentally friendly aqueous-solution-based method has been adopted to prepare gadolinium-doped hafnium oxide(HfO2) gate dielectric thin films.By adjusting the gadolinium(Gd) doping co...In this work,a non-toxic and environmentally friendly aqueous-solution-based method has been adopted to prepare gadolinium-doped hafnium oxide(HfO2) gate dielectric thin films.By adjusting the gadolinium(Gd) doping concentration,the oxygen vacancy content,band offset,interface trap density,and dielectric constant of HfGdOx(HGO) thin films have been optimized.Results have confirmed that HGO thin films with Gd doping ratio of 15 at.% have demonstrated appropriate dielectric constant of 27.1 and lower leakage current density of 5.8×10-9 A cm-2.Amorphous indium-gallium-zinc oxide(α-IGZO) thin film transistors(TFTs) based on HGO thin film(Gd:15 at.%) as gate dielectric layer have exhibited excellent electrical performance,such as larger saturated carrier mobility(μsat) of 20.1 cm2 V-1 S-1,high on/off current ratio(Ion/Ioff) of ~108,smaller sub-threshold swing(SS) of 0.07 V decade-1,and a negligible threshold voltage shift(ΔVTH) of 0.08 V under positive bias stress(PBS) for 7200 s.To confirm its potential application in logic circuit,a resistor-loaded inverter based on HGO/α-IGZO TFTs has been constructed.A high voltage gain of 19.8 and stable full swing characteristics have been detected.As a result,it can be concluded that aqueous-solution-driven HGO dielectrics have potential application in high resolution flat panel displays and ultra-large-scale integrated logic circuits.展开更多
Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the n...Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the novel non-metal elements(B,P,and S)doped g-C_(3)N_(4)tubes(B-CNT,P-CNT,and S-CNT)photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C_(3)N_(4)tubes(CNT)materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H_(2)O_(2)production with the formation rate constants values of 42.31μM min^(-1),24.95μM min^(-1),and 24.22μM min^(-1),respectively,which is higher than that of bulk CN(16.40μM min^(-1)).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electronhole carriers.The results have shown great potential for the practical application of CNT photocatalysts.展开更多
In this work,modified g-C_(3)N_(4) was fabricated successfully by calcination of ionic liquid(IL) and urea.The addition of IL changed the polymerization mode of urea,induced the self-assembly of urea molecules,modifie...In this work,modified g-C_(3)N_(4) was fabricated successfully by calcination of ionic liquid(IL) and urea.The addition of IL changed the polymerization mode of urea,induced the self-assembly of urea molecules,modified the morphological structure of the tightly packed g-C_(3)N_(4),and extended the electron conjugation system.When using 1-butyl-3-methylimidazolium chloride([Bmim]Cl) as a modifier,the heteroatom Cl could be inserted into the g-C_(3)N_(4) to optimize the electronic structure.The results of characterizations indicate that the unique structure of modified g-C_(3)N_(4) has an expanded electron delocalization range,introduces an interlayer charge transmission channel,promotes the charge transmission,reduces the band gap,enhances the absorption of visible light,and inhibits electron-hole recombination.Modified g-C_(3)N_(4) showed excellent photocatalytic performance for the degradation of rhodamine B and tetracycline.Furthermore,the effect of different anions in 1-butyl-3-methylimidazolium salts([Bmim]Cl,[Bmim]Br,[Bmim][BF_(4)],and [Bmim][PF_6]) on the structure and function of g-C_(3) N_(4) are discussed.展开更多
Even though transition metal carbonates(TMCs, TM = Fe, Mn, Co, Ni etc.), show high theoretical capacities, rich reserves and environmental friendliness as anodes for lithium-ion batteries(LIBs), they suffer from slugg...Even though transition metal carbonates(TMCs, TM = Fe, Mn, Co, Ni etc.), show high theoretical capacities, rich reserves and environmental friendliness as anodes for lithium-ion batteries(LIBs), they suffer from sluggish electronic/ionic conductivities and huge volume variation, which severely deteriorate the rate capacities and cycling performances. Understanding the intrinsic reaction mechanism and further developing ideal TMC-based anode with high specific capacity, excellent rate capabilities, and longterm cycling stability are critical for the practical application of TMCs. In this review, we firstly focus on the fundamental electrochemical energy-storage mechanisms of TMCs, in terms of conversionreaction process, pseudocapacitance-type charge storage, valence change for charge storage and catalytic conversion mechanisms. Based on the reaction mechanisms, various modification strategies to improve the electrochemical performance of TMCs are summarized, covering:(i) micro-nano structural engineering, in which the influence factors on the morphology are discussed, and multiple architectures are listed;(ii) elemental doping, in which the intrinsic mechanisms of metal/nonmetal elements doping on the electrochemical performance are deeply explored;(iii) multifunctional compositing strategies, in which the specific affections on structure, electronic conductivity and chemo-mechanical stability are summarized.Finally, the key challenges and opportunities to develop high-performance TMCs are discussed and some solutions are also proposed. This timely review sheds light on the path towards achieving cost-effective and safe LIBs with high energy density and long cycling life using TMCs-based anode materials.展开更多
Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.De...Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.Designing practical electrocatalysts by introducing defect engineering,such as hybrid structure,surface vacancies,functional modification,and structural distortions,is proven to be a dependable solution for fabricating electrocatalysts with high catalytic activities,robust stability,and good practicability.This review is an overview of some relevant reports about the effects of defect engineering on the electrocatalytic water splitting performance of electrocatalysts.In detail,the types of defects,the preparation and characterization methods,and catalytic performances of electrocatalysts are presented,emphasizing the effects of the introduced defects on the electronic structures of electrocatalysts and the optimization of the intermediates'adsorption energy throughout the review.Finally,the existing challenges and personal perspectives of possible strategies for enhancing the catalytic performances of electrocatalysts are proposed.An in-depth understanding of the effects of defect engineering on the catalytic performance of electrocatalysts will light the way to design high-efficiency electrocatalysts for water splitting and other possible applications.展开更多
Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electroch...Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electrochemical cell(R-PCEC)toward the sustainable hydrogen production and utilization.However,enhancement of their activity and stability remains challenging.Herein,we develop the Ta-regulated BaCo_(0.7)Fe_(0.3)O_(3-δ)perovskite oxygen electrode(Ba(Co_(0.7)Fe_(0.3))_(1-x)Ta_xO_(3-δ))with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and OER.As-fabricated R-PCEC with(Ba(Co_(0.7)Fe_(0.3))_(0.9)Ta_(0.1)O_(3-δ))(BCFT10)oxygen electrode performs high power density of 1.47 W·cm^(-2)at 650℃in fuel cell mode,and the current density is up to-2.11 A·cm^(-2)at 1.4 V at 650℃in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis modes.Importantly,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.展开更多
基金Project supported by the National Key R&D Program of China(2022YFB3505301)the National Key R&D Program of Shanxi Province(202302050201014)+2 种基金the National Natural Science Foundation of China(12304148)the Natural Science Basic Research Program of Shanxi Province(202203021222219)the China Postdoctoral Science Foundation(2023M731452)。
文摘Previous studies have demonstrated that increasing Fe doping content can enhance the saturation magnetization and maximum energy product of 2:17-type Sm-Co rare-earth permanent magnets.Howeve r,syste matic theo retical calculations and the effects of other transition metal dopants have yet to be explored.This study employed first-principles computational methods to investigate the effects of doping with 3d and Zr transition metal elements on the structural stability,magnetic properties,and electronic structure of Sm_(2)Co_(17)permanent magnets.The results indicate that Sc and Zr tend to occupy the Sm-6c site,while Ni,Cu and Zn preferentially occupy the 18h site,and Ti,V,Cr,Mn and Fe primarily occupy the Co-6c site.Except for V and Cu,all other elements effectively improve the structural stability of the doped systems.Additionally,Mn and Fe doping can significantly enhance the total magnetic moment and magnetocrystalline anisotropy energies of the Sm_(2)Co_(17)system,while Cr only increases the total magnetic moment.More importantly,doping with Cr,Mn and Fe within the doping co ntent range of9.8 at%<x<35.29 at% can simultaneously improve the structural stability,total magnetic moment and magnetocrystalline anisotropy energy of the Sm_(2)Co_(17) system.Our study provides valuable theoretical guidance for experimental exploration and is expected to promote the development and application of novel rare-earth permanent magnetic materials.
基金TheprojectisfinanciallysupportedbytheScienceResearchFoundationofOrdnanceEngineeringCollege (No .yjjxm0 0 0 6 )
文摘The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures,and the capacity decay during repeated charge-discharge cycles and the self-discharge are both suppressed, while the rate capability decreases.The alloy containing zirconium exhibits a longer cycle life and a better rate capability,but a much lower discharge capacity.The addition of titanium improves the rate capability, but the capacity decreases greatly.An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti,which improves the discharge-rate characteristics,and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.
基金financially supported by the National High Technology Research and Development Program of China (No. 2011AA03A402)
文摘A systematical investigation was carried out on structure and magnetic properties in SmFe_(9-x)V_(x)(x=0.4,0.8,1.2)compounds prepared by a single-roller quenching method.The high cool-down rate leads to metastable TbCu_(7) phase in the parent compound,which gradually transforms into equilibrium ThMn_(12) structure with V-doping content increasing.The Curie temperature increases from 470 to 590 K with V doping,which is consistent with the phase transformation.Surprisingly,simultaneous increase in both coercivity and remanence is resulted by V doping,reaching the highest value of 685 kA·m^(-1)and 44.8×10^(-3)A·m^(2)·g^(-1)in x=1.2 compound,respectively.This phenomenon can be explained by the combination of phase transformation and intergranular exchange coupling throughδM-H plots.
基金Project(2009K06_03) supported by the Scientific and Technological Program of Shaanxi Province,China
文摘Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.
基金financially supported by the National Natural Science Foundation of China(Nos.52263010,51902090)Henan Key Research Project Plan for Higher Education Institutions(No.23A150038)+5 种基金2023 Introduction of studying abroad talent program,“"111"Project(No.D17007)Henan Provincial Key Scientific Research Project of Colleges and Universities(No.23A150038)Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National students'platform for innovation and entrepreneurship training program(No.201910476010)the China Postdoctoral Science Foundation(No.2019 M652546)the Henan Province Postdoctoral Start-Up Foundation(No.1901017).
文摘P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirable electrochemical performances by inducing anion/cation ions,changing morphology,adjusting valence,etc.In this work,several same-period elements of Sc,Ti,V,Cr,Fe,Cu and Zn are doped into Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)O_(2)cathodes,which are manipulated by ions radii and valence state,further studied by operando X-ray powder diffraction patterns(XRD).As a result,the Cu^(2+)doped cathode performed higher rate capacities(as high as 86 mAh/g even at 10 C)and more stable structures(capacity retention of~89.4%for 100 cycles),which owing to the synergistic effect among the tightened TMO_(2)layer,enlarged d-spacing,reduce O-O electrostatic repulsion,ameliorate lattice distortion as well as mitigate ordering of Na^(+)/vacancy.
基金Funded by National Key Research and Development Program of China(No.2017YFB0310400)the National Natural Science Foundation of China(Nos.51872217,51932006,51972246 and 51521001)+3 种基金Fundamental Research Funds for the Central Universities in ChinaState Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),the Joint Fund(No.6141A02022255)the Major Program of the Specialized Technological Innovation of HuBei Province,China(No.2019AFA176)the“111”Project(No.B13035)。
文摘We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.
基金NSF of China,Grant/Award Number:22205125Youth Special Program for Innovation of Science and Technology,Grant/Award Number:QNZX202307Program for Innovative Research Team(in Science and Technology)at the University of Henan Province(IRTSTHN)。
文摘The restacking and oxidizable nature of vanadium-based carbon/nitride(V_(2)C-MXene)poses a significant challenge.Herein,tellurium(Te)-doped V_(2)C/V_(2)O_(3) electrocatalyst is constructed via mild H_(2)O_(2) oxidation and calcination treatments.Especially,this work rationally exploits the inherent easy oxidation characteristic associated with MXene to alter the interfacial information,thereby obtaining stable self-generated vanadium-based heterointerfaces.Meanwhile,the microetching effect of H_(2)O_(2) creates numerous pores to address the restacking issues.Besides,Te element doping settles the issue of awkward levels of absorption/desorption ability of intermediates.The electrocatalyst obtains an unparalleled hydrogen evolution reaction and oxygen evolution reaction with the overpotential of 83.5 and 279.8 mV at−10 and 10 mA cm^(−2),respectively.In addition,the overall water-splitting device demonstrates a low cell voltage of 1.41 V to obtain 10 mA cm^(−2).Overall,the inherent drawbacks of MXene can be turned into benefits based on the planning strategy to create these electrocatalysts with desirable reaction kinetics.
基金supported by National Key R&D Program of China(2021YFB4001401)National Natural Science Foundation of China(52272190,22178023).
文摘Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.
基金the National Key R&D Program of China(No.2023YFC3009501)the National Natural Science Foundation of China(No.52374298)+1 种基金the project of State Key Laboratory of Explosion Science and Safety Protection(Beijing Institute of Technology,No.QNKT23-17)Aeronautical Science Foundation of China(No.20174072003).
文摘Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-doped LLZO(LLZGO),which exhibits high ionic conductivity.However,the limited size of the Liþtransport bottleneck restricts its high-current discharging performance.The present study focuses on the synthesis of Ga^(3+)þand Ba^(2+)þco-doped LLZO(LLZGBO)and investigates the influence of doping contents on the morphology,crystal structure,Liþtransport bottleneck size,and ionic conductivity.In particular,Ga_(0.32)Ba_(0.15)exhibits the highest ionic conductivity(6.11E-2 S cm^(-1) at 550 C)in comparison with other compositions,which can be attributed to its higher-energy morphology,larger bottleneck and unique Liþtransport channel.In addition to Ba^(2+),Sr^(2+)þand Ca^(2+)have been co-doped with Ga3þinto LLZO,respectively,to study the effect of doping ion radius on crystal structures and the properties of electrolytes.The characterization results demonstrate that the easier Liþtransport and higher ionic conductivity can be obtained when the electrolyte is doped with larger-radius ions.As a result,the assembled thermal battery with Ga_(0.32)Ba_(0.15)-LLZO electrolyte exhibits a remarkable voltage platform of 1.81 V and a high specific capacity of 455.65 mA h g^(-1) at an elevated temperature of 525℃.The discharge specific capacity of the thermal cell at 500 mA amounts to 63%of that at 100 mA,showcasing exceptional high-current discharging performance.When assembled as prototypes with fourteen single cells connected in series,the thermal batteries deliver an activation time of 38 ms and a discharge time of 32 s with the current density of 100 mA cm^(-2).These findings suggest that Ga,Ba co-doped LLZO solid-state electrolytes with high ionic conductivities holds great potential for high-capacity,quick-initiating and high-current discharging thermal batteries.
基金supported by the National Natural Science Foundation of China(NSFC)(22105059,22179078,22479115)the Beijing-Tianjin-Hebei Basic Research Cooperation Special Project(B2024204027)+5 种基金the Youth Top-notch Talent Foundation of Hebei Provincial Universities(BJK2022023)the Natural Science Foundation of Hebei Province(B2023204006)the talent training project of Hebei province(No.B20231004)the Innovative Research Team of High-level Local Universities in ShanghaiZhejiang Provincial Natural Science Foundation of China(LY24E020002)Wenzhou basic scientific research project(G20240022)。
文摘Sodium-ion batteries have emerged as promising candidates for next-generation large-scale energy storage systems due to the abundance of sodium resources,low solvation energy,and cost-effectiveness.Among the available cathode materials,vanadium-based sodium phosphate cathodes are particularly notable for their high operating voltage,excellent thermal stability,and superior cycling performance.However,these materials face significant challenges,including sluggish reaction kinetics,the toxicity of vanadium,and poor electronic conductivity.To overcome these limitations and enhance electrochemical performance,various strategies have been explored.These include morphology regulation via diverse synthesis routes and electronic structure optimization through metal doping,which effectively improve the diffusion of Na+and electrons in vanadium-based phosphate cathodes.This review provides a comprehensive overview of the challenges associated with V-based polyanion cathodes and examines the role of morphology and electronic structure design in enhancing performance.Key vanadium-based phosphate frameworks,such as orthophosphates(Na_(3)V_(2)(PO_(4))_(3)),pyrophosphates(NaVP_(2)O_(7),Na_(2)(VO)P_(2)O_(7),Na_(7)V_(3)(P_(2)O_(7))_(4)),and mixed phosphates(Na_(7)V_(4)(P_(2)O_(7))_(4)PO_(4)),are discussed in detail,highlighting recent advances and insights into their structure-property relationships.The design of cathode material morphology offers an effective approach to optimizing material structures,compositions,porosity,and ion/electron diffusion pathways.Simultaneously,electronic structure tuning through element doping allows for the regulation of band structures,electron distribution,diffusion barriers,and the intrinsic conductivity of phosphate compounds.Addressing the challenges associated with vanadium-based sodium phosphate cathode materials,this study proposes feasible solutions and outlines future research directions toward advancement of high-performance vanadium-based polyanion cathodes.
基金supported by Guangzhou Basic and Applied Basic Research Foundation(Grant No.2023B151520013)the National Natural Sciences Foundation of China(Grant No.92165204)+2 种基金the National Key Research and Development Program of China(Grant Nos.2023YFF0718400 and 2022YFA1403301)the Fund from the Research Center for Magnetoelectric Physics of Guangdong Province,China(Grant No.2024B0303390001)the Independent Fund of the State Key Laboratory of Optoelectronic&Materials and Technologies(Sun Yat-sen University)(Grant No.OEMT-2023-ZTS-01)。
文摘Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At elevated temperatures,a spin-reorientation transition induces a ferrimagnetic state(FIM1)with in-plane magnetic moments,accompanied by a nonmonotonic Hall response that differs markedly from the low-temperature behavior.Upon indium doping,the long-range ferrimagnetic transition is progressively suppressed to lower temperatures,along with a noticeable reduction in magnetic anisotropy.Interestingly,at a doping level of x=1.2,the FIM1 state observed in the parent compound is completely eliminated.These systematic changes in magnetic ordering and transport properties underscore a coherent evolution of the electronic and magnetic states with doping,offering critical insights into the interplay among lattice structure,magnetism,and electronic behavior in kagome lattices.
基金This work is financially supported by the Natural Science Foundation of Hunan Province (No. 01JJY3004) and Technology of China National Packaging Corporation.
文摘Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink.
基金supported by the National Natural Science Foundation of China(Nos.52271172,and 51971085).
文摘Ni-Mn-Ti Heusler alloys have great potential for elastocaloric refrigeration due to the colossal caloric effect and good mechanical properties. However, theoretical calculations on the characterization of the elastocaloric effect are rare. An important parameter to evaluate the elastocaloric effect is the transformation entropy change, whose main source is the vibrational entropy change (ΔS_(vib)). Unfortunately, the widely used quasiharmonic approximation method fails in the prediction of the vibrational entropy for high-temperature austenite due to its dynamical instability at 0 K. To solve this problem, the temperature dependent effective potential method was used considering the temperature and anharmonic effect. Sc, V, and Zr doping at the Ti sites in B2 disordered Ni_(8)Mn_(5)Ti_(3) were studied about phase stability, martensitic transformation, and elastocaloric properties. The results revealed the austenitic structures of all the doping systems exhibit antiferromagnetic coupling characteristics at 300 K due to the temperature effect. Sc and Zr doping at the Ti sites decreased the ΔS_(vib) value, whereas V doping at the Ti site increased the ΔS_(vib) value. Further analysis proved the important evaluation criterion that the ΔS_(vib) value increases with the tetragonal distortion ratio and volume change, which has important guiding significance for improving the elastocaloric effect. Besides, the calculations of elastic constants presented all the doping systems maintain outstanding ductility evaluated from the B/G ratio. This work provides an effective strategy for designing excellent elastocaloric material with large vibrational entropy change and good mechanical properties.
基金supported by the Natural Science Foundation Project of Chongqing Science and Technology Commission (CQ CSTC)(No.cstc2018jcyjAX0320)the Fundamental Research Funds for the Central Universities(No.2018CDXYCH0013)+1 种基金Financial supports from the National Nature Science Foundation of China(NSFC)(Nos.91647211 and No.51539001)the Innovative Research Group of NSFC(No.51721006)
文摘In this study,a novel class of niobium(Nb) doped titanate nanoflakes(TNFs) are fabricated through a onestep hydrothermal method.Nb doping affects the curving of titanate nanosheet,leading to the formation of nanoflake structure.In addition,Nb5+ filled in the interlayers of [TiO6] alters the light adsorption property of pristine titanate.The band gap of Nb-TNFs is narrowed to 2.85 eV,while neat titanate nano tubes(TNTs) is 3.4 eV.The enhanced visible light adsorption significantly enhances the visible-lightdriven activity of Nb-TNFs for ibuprofen(IBP) degradation.The pseudo-first order kinetics constant for Nb-TNFs is calculated to be 1.04 h^-1,while no obvious removal is observed for TNTs.Photo-generated holes(h^+) and hydroxyl radicals(·OH) are responsible for IBP degradation.The photocatalytic activity of Nb-TNFs depends on pH condition,and the optimal pH value is found to be 5.In addition,Nb-TNFs exhibited superior photo-stability during the reuse cycles.The results demonstrated Nb-TNFs are very promising in photocatalytic water purification.
基金financially supported by the National Natural Science Foundation of China (Nos. 11774001 and 51572002)Open fund for Discipline Construction, Institute of Physical Science and Information Technology, Anhui University (No. S01003101)。
文摘In this work,a non-toxic and environmentally friendly aqueous-solution-based method has been adopted to prepare gadolinium-doped hafnium oxide(HfO2) gate dielectric thin films.By adjusting the gadolinium(Gd) doping concentration,the oxygen vacancy content,band offset,interface trap density,and dielectric constant of HfGdOx(HGO) thin films have been optimized.Results have confirmed that HGO thin films with Gd doping ratio of 15 at.% have demonstrated appropriate dielectric constant of 27.1 and lower leakage current density of 5.8×10-9 A cm-2.Amorphous indium-gallium-zinc oxide(α-IGZO) thin film transistors(TFTs) based on HGO thin film(Gd:15 at.%) as gate dielectric layer have exhibited excellent electrical performance,such as larger saturated carrier mobility(μsat) of 20.1 cm2 V-1 S-1,high on/off current ratio(Ion/Ioff) of ~108,smaller sub-threshold swing(SS) of 0.07 V decade-1,and a negligible threshold voltage shift(ΔVTH) of 0.08 V under positive bias stress(PBS) for 7200 s.To confirm its potential application in logic circuit,a resistor-loaded inverter based on HGO/α-IGZO TFTs has been constructed.A high voltage gain of 19.8 and stable full swing characteristics have been detected.As a result,it can be concluded that aqueous-solution-driven HGO dielectrics have potential application in high resolution flat panel displays and ultra-large-scale integrated logic circuits.
基金financially supported by the Jiangsu Key Science and Technology Project(No.BE2019108)the National Natural Science Foundation of China(No.21173041)the Opening Project of Jiangsu Key Laboratory of Advanced Metallic Materials,China。
文摘Developing environmentally friendly methods to produce hydrogen peroxide(H_(2)O_(2))has received increasing attention.Photocatalysis has been proved to be a sustainable technology for H_(2)O_(2)production.Herein,the novel non-metal elements(B,P,and S)doped g-C_(3)N_(4)tubes(B-CNT,P-CNT,and S-CNT)photocatalysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C_(3)N_(4)tubes(CNT)materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H_(2)O_(2)production with the formation rate constants values of 42.31μM min^(-1),24.95μM min^(-1),and 24.22μM min^(-1),respectively,which is higher than that of bulk CN(16.40μM min^(-1)).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electronhole carriers.The results have shown great potential for the practical application of CNT photocatalysts.
基金support provided by the National Natural Science Foundation of China (21878164, 21978143)Shandong Provincial Key Research and Development Program (2019GGX102029)+1 种基金“Qing Chuang Science and Technology Plan” Project of Colleges and Universities in Shandong Province (2020KJC005)State Key Laboratory of Materials-Oriented Chemical Engineering-Open Fund (KL19-08)。
文摘In this work,modified g-C_(3)N_(4) was fabricated successfully by calcination of ionic liquid(IL) and urea.The addition of IL changed the polymerization mode of urea,induced the self-assembly of urea molecules,modified the morphological structure of the tightly packed g-C_(3)N_(4),and extended the electron conjugation system.When using 1-butyl-3-methylimidazolium chloride([Bmim]Cl) as a modifier,the heteroatom Cl could be inserted into the g-C_(3)N_(4) to optimize the electronic structure.The results of characterizations indicate that the unique structure of modified g-C_(3)N_(4) has an expanded electron delocalization range,introduces an interlayer charge transmission channel,promotes the charge transmission,reduces the band gap,enhances the absorption of visible light,and inhibits electron-hole recombination.Modified g-C_(3)N_(4) showed excellent photocatalytic performance for the degradation of rhodamine B and tetracycline.Furthermore,the effect of different anions in 1-butyl-3-methylimidazolium salts([Bmim]Cl,[Bmim]Br,[Bmim][BF_(4)],and [Bmim][PF_6]) on the structure and function of g-C_(3) N_(4) are discussed.
基金financially supported by the National Natural Science Foundation of China(51802091,51902102,22075074,U21A2081)the Outstanding Young Scientists Research Funds from Hunan Province(2020JJ2004)+3 种基金the Major Science and Technology Program of Hunan Province(2020WK2013)the China Postdoctoral Science Foundation(2020 M672478)the Natural Science Foundation of Hunan Province(2020JJ5035,2021JJ40047,2020JJ5042)the Major Science and Technology Program of Changsha(kq1804010)。
文摘Even though transition metal carbonates(TMCs, TM = Fe, Mn, Co, Ni etc.), show high theoretical capacities, rich reserves and environmental friendliness as anodes for lithium-ion batteries(LIBs), they suffer from sluggish electronic/ionic conductivities and huge volume variation, which severely deteriorate the rate capacities and cycling performances. Understanding the intrinsic reaction mechanism and further developing ideal TMC-based anode with high specific capacity, excellent rate capabilities, and longterm cycling stability are critical for the practical application of TMCs. In this review, we firstly focus on the fundamental electrochemical energy-storage mechanisms of TMCs, in terms of conversionreaction process, pseudocapacitance-type charge storage, valence change for charge storage and catalytic conversion mechanisms. Based on the reaction mechanisms, various modification strategies to improve the electrochemical performance of TMCs are summarized, covering:(i) micro-nano structural engineering, in which the influence factors on the morphology are discussed, and multiple architectures are listed;(ii) elemental doping, in which the intrinsic mechanisms of metal/nonmetal elements doping on the electrochemical performance are deeply explored;(iii) multifunctional compositing strategies, in which the specific affections on structure, electronic conductivity and chemo-mechanical stability are summarized.Finally, the key challenges and opportunities to develop high-performance TMCs are discussed and some solutions are also proposed. This timely review sheds light on the path towards achieving cost-effective and safe LIBs with high energy density and long cycling life using TMCs-based anode materials.
基金National Natural Science Foundation of China,Grant/Award Number:52271200Scientific and Technological Innovation Foundation of Foshan,Grant/Award Number:BK20BE009+1 种基金the Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-TP-18-079A1Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2020A1515110460,ORCID:http://orcid.org/0000-0002-0870-2248。
文摘Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.Designing practical electrocatalysts by introducing defect engineering,such as hybrid structure,surface vacancies,functional modification,and structural distortions,is proven to be a dependable solution for fabricating electrocatalysts with high catalytic activities,robust stability,and good practicability.This review is an overview of some relevant reports about the effects of defect engineering on the electrocatalytic water splitting performance of electrocatalysts.In detail,the types of defects,the preparation and characterization methods,and catalytic performances of electrocatalysts are presented,emphasizing the effects of the introduced defects on the electronic structures of electrocatalysts and the optimization of the intermediates'adsorption energy throughout the review.Finally,the existing challenges and personal perspectives of possible strategies for enhancing the catalytic performances of electrocatalysts are proposed.An in-depth understanding of the effects of defect engineering on the catalytic performance of electrocatalysts will light the way to design high-efficiency electrocatalysts for water splitting and other possible applications.
基金financially supported by the National Key R&D Program of China(No.2022YFB4002201)the National Natural Science Foundation of China(Nos.52072362 and 52302119)+3 种基金Jilin Province Science and Technology Development Plan Funding Project(Nos.SKL202302039 and 20220201112GX)Jiangsu Province Innovation Support Program(No.BE2023092-2)Youth Innovation Promotion Association CAS(No.2021223)Open Funds of the State Key Laboratory of Rare Earth Resource Utilization(No.RERU2022008)。
文摘Perovskite oxides with diverse composition and structure have exhibited grand advances in boosting the oxygen reduction and evolution reaction(ORR/OER),which are essential for the reversible protonic ceramic electrochemical cell(R-PCEC)toward the sustainable hydrogen production and utilization.However,enhancement of their activity and stability remains challenging.Herein,we develop the Ta-regulated BaCo_(0.7)Fe_(0.3)O_(3-δ)perovskite oxygen electrode(Ba(Co_(0.7)Fe_(0.3))_(1-x)Ta_xO_(3-δ))with abundant oxygen defects and achieve the simultaneous enhancement in the electrocatalytic activity and stability toward ORR and OER.As-fabricated R-PCEC with(Ba(Co_(0.7)Fe_(0.3))_(0.9)Ta_(0.1)O_(3-δ))(BCFT10)oxygen electrode performs high power density of 1.47 W·cm^(-2)at 650℃in fuel cell mode,and the current density is up to-2.11 A·cm^(-2)at 1.4 V at 650℃in electrolysis mode,as well as the good stability in both the fuel cell and electrolysis modes.Importantly,the cell also demonstrates a stable cycling operation between fuel cell and electrolysis mode,suggesting a great potential of BCFT10 as oxygen electrode material for R-PCECs.
