本文报道了一种适应于高效稳定的CO-CO_(2)相互转化的可逆固体氧化物电池(RSOC)相变燃料电极.该燃料电极由FeRu双金属纳米催化剂和Ruddlesden-Popper相Pr_(0.8)Sr_(1.2)Fe_(1-x-y)Ru_(x)Mo_(y)O_(4)氧化物复合而成(FeRu@PSFRM).固体氧...本文报道了一种适应于高效稳定的CO-CO_(2)相互转化的可逆固体氧化物电池(RSOC)相变燃料电极.该燃料电极由FeRu双金属纳米催化剂和Ruddlesden-Popper相Pr_(0.8)Sr_(1.2)Fe_(1-x-y)Ru_(x)Mo_(y)O_(4)氧化物复合而成(FeRu@PSFRM).固体氧化物燃料电池(SOFC)模式时,单电池800℃时的最大输出功率密度可以达到170 W cm^(-2);而在固体氧化物电解池(SOEC)模式下,800℃、1.3 V时电解池的电解电流密度达到-0.256 A cm^(-2).在SOFC-SOEC循环测试过程中,RSOC中CO-CO_(2)相互转化过程经历了“活化-稳定-衰退”三个明显阶段.幸运的是,性能衰退的燃料电极可通过“原位氧化-还原”处理实现性能再生,有效提升该电池的使用寿命.研究结果表明,原位脱溶形成的FeRu@PSFRM材料是一种极具应用潜力的燃料电极候选材料,以期实现高效稳定的CO-CO_(2)相互转化.展开更多
Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7...Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.展开更多
Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain ch...Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain challenging.Herein,we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni,Fe-contained Ruddlesden-Popper(RP)-type perovskites(La_(0.125)Sr_(0.875))n+1(Ni_(0.25)Fe_(0.75))nO3n+1(n=1,2,3),where the material with n=3 shows the best OER performance in alkaline media.Soft X-ray absorption spectroscopy spectra before and after OER reveal that the material with n=3 shows enhanced Ni/Fe-O covalency to boost the electron transfer as compared to those with n=1 and n=2.Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system,where such unique synergy reaches the optimum at n=3.Besides,as n increases,the proportion of unstable rock-salt layers accordingly decreases and the leaching of ions(especially Sr^(2+))into the electrolyte is suppressed,which induces a decrease in the leaching of active Fe ions,ultimately leading to enhanced stability.This work provides a new avenue for rational catalyst design through the dimensional strategy.展开更多
Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of ...Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of bulky organic cation spacers limits the performance of 2DRP PSCs.Inspired by the Asite cation alloying strategy in 3D perovskites,2DRP perovskites with a binary spacer can promote charge transporting compared to the unary spacer counterparts.Herein,the superior MA-based 2DRP perovskite films with a binary spacer,including 3-guanidinopropanoic acid(GPA)and 4-fluorophenethylamine(FPEA)are realized.These films(GPA_(0.85)FPEA_(0.15))_(2)MA_(4)Pb_5I_(16)show good morphology,large grain size,decreased trap state density,and preferential orientation of the as-prepared film.Accordingly,the present 2DRP-based PSC with the binary spacer achieves a remarkable efficiency of 18.37%with a V_(OC)of1.15 V,a J_(SC)of 20.13 mA cm^(-2),and an FF of 79.23%.To our knowledge,the PCE value should be the highest for binary spacer MA-based 2DRP(n≤5)PSCs to date.Importantly,owing to the hydrophobic fluorine group of FPEA and the enhanced interlayer interaction by FPEA,the unencapsulated 2DRP PSCs based on binary spacers exhibit much excellent humidity stability and thermal stability than the unary spacer counterparts.展开更多
A highly efficient Ruddlesden-Popper structure anode material with a formula of Sr_(3)Fe_(1.3)Mo_(0.5)Ni_(0.2)O_(7-δ)(RP-SFMN)has been developed for hydrocarbon fueled solid oxide fuel cells(HF-SOFC)application.It is...A highly efficient Ruddlesden-Popper structure anode material with a formula of Sr_(3)Fe_(1.3)Mo_(0.5)Ni_(0.2)O_(7-δ)(RP-SFMN)has been developed for hydrocarbon fueled solid oxide fuel cells(HF-SOFC)application.It is demonstrated that a nanostructured RP-SFMN anode decorated with in-situ exsolved Ni nanoparticles(Ni@RP-SFMN)has been successfully prepared by annealing the anode in reducing atmosphere similar to the operating conditions.The phase compositions,valence states,morphologies,and electrocatalytic activities of RP-SFMN material have been characterized in detail.In addition,the in-situ exsolution mechanism of the metallic Ni phase from the parent oxide is clearly explained by using density function theory calculation.The peak output power density at 800℃ is significantly enhanced from 0.163 to 0.409 W/cm^(2)while the electrode polarization resistance is effectively lowered from 0.96 to 0.30Ωcm^(2)by the substitution of B-site Fe by Ni,which is attributed to the improved electrocatalytic activities induced by the in-situ exsolved Ni nanocatalysts.Moreover,the single cell with RP-SFMN anode exhibits good stability in 3%H_(2)O humidified H_(2)and syngas for 110 and 60 h at 800℃,respectively.Our findings indicate that RP-SFMN is a greatly promising anode candidate of HF-SOFCs due to its good electrochemical performance and stability during the operation.展开更多
Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP micro...Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.展开更多
Solid-oxide fuel cells(SOFCs)offer great promise for producing electricity using a wide variety of fuels such as natural gas,coal gas and gasified carbonaceous solids;however,conventional nickel-based anodes face grea...Solid-oxide fuel cells(SOFCs)offer great promise for producing electricity using a wide variety of fuels such as natural gas,coal gas and gasified carbonaceous solids;however,conventional nickel-based anodes face great challenges due to contaminants in readily available fuels,especially sulphur-containing compounds.Thus,the development of new anode materials that can suppress sulphur poisoning is crucial to the realization of fuel-flexible and cost-effective SOFCs.In this work,La_(0.1)Sr_(1.9)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)(LSFNM)and Pr_(0.1)Sr_(1.9)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)(PSFNM)materials have been synthesized using a sol-gel method in air and investigated as anode mater-ials for SOFCs.Metallic nanoparticle-decorated ceramic anodes were obtained by the reduction of LSFNM and PSFNM in H_(2)at 850℃,forming a Ruddlesden-Popper oxide with exsolved FeNi3 bimetallic nanoparticles.The electrochemical performance of the Sr_(2)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)ceramic anode was greatly enhanced by La doping of A-sites,resulting in a 44%decrease in the polarization resistance in reducing atmosphere.The maximum power densities of Sr-and Mg-doped LaGaO_(3)(LSGM)(300μm)electrolyte-supported single cells with LSFNM as the anode reached 1.371 W cm^(-2)in H_(2)and 1.306 W cm^(-2)in 50 ppm H_(2)S-H_(2)at 850℃.Meanwhile,PSFNM showed improved sulphur tolerance,which could be fully recovered after six cycles from H_(2)to 50 ppm H_(2)S-H_(2)operation.This study indicates that LSFNM and PSFNM are promising high-performance anodes for SOFCs.展开更多
Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stabi...Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stability.Two-dimensional(2D)Ruddlesden-Popper(RP)perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations.However,the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells.Moreover,controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult.Herein,we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods.Furthermore,the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.展开更多
Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)w...Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)was discovered to be an efficient OER catalyst because of its unique structure,which consists of layers of both rock salt and perovskite phases simultaneously.In this study,we prepared a series of B-site mixed,Ruddlesden-Popper phase of Sr_(2)(Ru_(x)Ir_(1-x))O_(4) and examined their electrocatalytic properties for OER in acidic media.Through partial substitution of Ru in the B-site of Ruddlesden-Popper phase materials,we achieved much enhanced OER performance for this series of Sr_(2)(Ru_(x)Ir_(1-x))O_(4)electrocatalysts,among which Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)exhibited the best catalytic activity with a current density of 8.06 m A/cm^(2) at 1.55 V and a Tafel slope of 47 m V/dec.This current density is three times higher than that of Sr_(2)Ir O_(4).The B-site mixed Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)retained good stability in acidic conditions for>24 h at 10 m A/cm^(2).A range of techniques were used to characterize the crystal and electronic structures of the Sr_(2)(Ru_(x)Ir_(1-x))O_(4)samples.Our data indicate that the improved OER performance can be correlated to the formation of high level of hydroxyl groups and the enhanced overlap between Ir/Ru 4d and O_(2)p orbitals,revealing a new way for the design of efficient OER electrocatalysts by regulating their composition and electronic structures.展开更多
The crucial component,bulky spacers,in two-dimensional Ruddlesden-Popper(2 DRP)layered tin(Sn)perovskites are highly limited by halide ammonium salts,leading to the insufficient control of complex crystallization proc...The crucial component,bulky spacers,in two-dimensional Ruddlesden-Popper(2 DRP)layered tin(Sn)perovskites are highly limited by halide ammonium salts,leading to the insufficient control of complex crystallization process due to the limited interaction between bulky spacers and 2 DRP perovskite frameworks.Here,we report an ionic liquid-bulky spacer,butylammounium acetate(BAAc O),for constructing efficient and stable 2 DRP Sn-based perovskite solar cells(PSCs).In contrast to the traditional halide ammonium bulky spacer,butylammounium iodide(BAI),the Ac O^(-)-functional group in BAAc O has a strong interaction with formamidine ions(FA^(+))and Sn2+.The inter-component interaction allows the formation of controllable intermediates for the favorable growth of smooth,dense,and highly oriented perovskite films.A PSC with power conversion efficiency of 10.36%(7.16%for BAI)is achieved,which is the highest report,along with improved stability with~90%retained after~600 h storage in N_(2) atmosphere without any encapsulation.展开更多
Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on a...Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.展开更多
In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membr...In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems.In this work,the authors’recent studies in this field are reviewed;the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’permselective layers based on research of their oxygen mobility and surface reactivity are presented.Ruddlesden-Popper phases Ln_(2-x)Ca_(x)NiO_(4+δ)(LnCNO)and perovskite-fluorite nanocomposites PrNi_(0.5)Co_(0.5)O_(3-δ)-Ce_(0.9)Y_(0.1)O_(2-δ)(PNC-YDC)were studied by isotope exchange of oxygen with C_(18)O_(2)and^(18)O_(2)in flow and closed reactors.For LnCNO a high oxygen mobility was shown(D*~10^(-7)cm^(2)/s at 700℃),being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen.For PNC-YDC dominated a wide fast diffusion channel via fluorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility(D*~10^(-8)cm^(2)/s at 700℃).After optimization of composition and nanodomain structure of these materials,as cathodes of SOFC they provided a high power density,while for asymmetric supported oxygen separation membranes-a high oxygen permeability.展开更多
Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrat...Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrated.However,the main challenge that currently limits the application of the perovskite solar cells is the long-term stability,which has ambient,thermal,and photo stability weaknesses.展开更多
The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well un...The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well understood.Therefore,the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart,to achieve optimal magnetocaloric performance.A series of self-doped Pr_(1.4+x)Sr_(1.6-x)Mn_(2)O_(7)(0.0≤x≤0.5)Ruddlesden-Popper(R-P)perovskite have been prepared through the solid-state sintering method.With increasing the Pr-stoichiometry,the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite structure.Due to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer(T=304 K)interactions towards the strong three-dimensional(T=308 K)interactions respectively.This series consistently develops thermomagnetic irreversibility in zero-field cooled(ZFC)-field cooled(FC)magnetization,which is indicative of a spin-glass state.The glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the surface.The maximum value of temperature average entropy change(TEC)and adiabatic temperature(ΔT)has enhanced nearly by 4 folds from 0.53 J kg^(-1)K^(-1),0.59 K(for x=0.0)up to 1.85 J kg^(-1)K^(-1),10 K(for x=0.5)at 2.5 T,respectively.Additionally,the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 T.Our findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.展开更多
In the present work,the crystal structure,ferroelectric and dielectric properties of the dense single-phase Li_(2)CaTa_(2)O_(7) ceramics with A-site ordered double-layer Ruddlesden-Popper structures have been investig...In the present work,the crystal structure,ferroelectric and dielectric properties of the dense single-phase Li_(2)CaTa_(2)O_(7) ceramics with A-site ordered double-layer Ruddlesden-Popper structures have been investigated by the experiments and first-principles calculations.A polar Pna21 phase was determined by the Rietveld refinement against the X-ray diffraction pattern at room temperature,and it was confirmed by its lowest calculated energy and rigid phonon modes.The ferroelectricity was found by observing the ferroelectric hysteresis loop at room temperature,and its remanent polarization was similar to the value calculated from the Berry phase and Born effective charge approaches.The ferroelectricity is a nonconventional proper one since its polarization is induced from the displacement of oxygen anions instead of tantalum cations based on the individual atomic polarization.A first-order transition from an antiferroelectric to paraelectric phase around 900 K was found by the DSC and variable-temperature dielectric measurements.From the present work,the room-temperature ferroelectricity is experimental confirmed in the present ceramics,inspiring the search for new ferroelectricity in the ceramics with A-site ordered Ruddlesden-Popper structures.展开更多
Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of de...Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(<460 nm)PeLEDs still lag far behind their red and green counterparts.Herein,a rapid crystallization method based on hot-antisolvent bathing is proposed for realization of deep-blue PeLEDs.By promoting immediate removal of the precursor solvent from the wet perovskite films,development of the quasi-two-dimensional(2D)Ruddlesden–Popper perovskite(2D-RPP)crystals with n values>3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained successfully.The uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge carriers.Thus,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully demonstrated.The color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.展开更多
基金supported by the start-up research funds from Wuhan Institute of Technology(K202201)Natural Science Foundation of Hubei Province of China(2024CFB755)+1 种基金National Natural Science Foundation of China(U21A20317)the Graduate Innovation Fund of Wuhan Institute of Technology(CX2023040)。
文摘本文报道了一种适应于高效稳定的CO-CO_(2)相互转化的可逆固体氧化物电池(RSOC)相变燃料电极.该燃料电极由FeRu双金属纳米催化剂和Ruddlesden-Popper相Pr_(0.8)Sr_(1.2)Fe_(1-x-y)Ru_(x)Mo_(y)O_(4)氧化物复合而成(FeRu@PSFRM).固体氧化物燃料电池(SOFC)模式时,单电池800℃时的最大输出功率密度可以达到170 W cm^(-2);而在固体氧化物电解池(SOEC)模式下,800℃、1.3 V时电解池的电解电流密度达到-0.256 A cm^(-2).在SOFC-SOEC循环测试过程中,RSOC中CO-CO_(2)相互转化过程经历了“活化-稳定-衰退”三个明显阶段.幸运的是,性能衰退的燃料电极可通过“原位氧化-还原”处理实现性能再生,有效提升该电池的使用寿命.研究结果表明,原位脱溶形成的FeRu@PSFRM材料是一种极具应用潜力的燃料电极候选材料,以期实现高效稳定的CO-CO_(2)相互转化.
基金supported by the Research Grants Council,University Grants Committee,Hong Kong SAR(Project Number:N_PolyU552/20)supported by the National Nature Science Foundation of China(22209138)Guangdong Basic and Applied Basic Research Foundation(2021A1515110464).
文摘Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515012878Natural Science Foundation of Anhui Province,Grant/Award Number:2008085ME134+2 种基金Australian Research Council Discovery Projects,Grant/Award Numbers:ARC DP200103315,ARC DP200103332Major Special Science and Technology Project of Anhui Province,Grant/Award Number:202103a07020007Key Research and Development Program of Anhui Province,Grant/Award Number:202104a05020057。
文摘Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain challenging.Herein,we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni,Fe-contained Ruddlesden-Popper(RP)-type perovskites(La_(0.125)Sr_(0.875))n+1(Ni_(0.25)Fe_(0.75))nO3n+1(n=1,2,3),where the material with n=3 shows the best OER performance in alkaline media.Soft X-ray absorption spectroscopy spectra before and after OER reveal that the material with n=3 shows enhanced Ni/Fe-O covalency to boost the electron transfer as compared to those with n=1 and n=2.Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system,where such unique synergy reaches the optimum at n=3.Besides,as n increases,the proportion of unstable rock-salt layers accordingly decreases and the leaching of ions(especially Sr^(2+))into the electrolyte is suppressed,which induces a decrease in the leaching of active Fe ions,ultimately leading to enhanced stability.This work provides a new avenue for rational catalyst design through the dimensional strategy.
基金financially supported by the Natural Science Foundation of China(Grant Nos.52372226,52173263,62004167)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant Nos.2022JM-315,2023-JC-QN-0643)+4 种基金the National Key R&D Program of China(Grant No.2022YFB3603703)the Qinchuangyuan High-level Talent Project of Shaanxi(Grant No.QCYRCXM-2022-219)the Ningbo Natural Science Foundation(Grant No.2022J061)the Key Research and Development Program of Shaanxi(Grant No.2023GXLH-091)the Shccig-Qinling Program and the Fundamental Research Funds for the Central Universities。
文摘Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of bulky organic cation spacers limits the performance of 2DRP PSCs.Inspired by the Asite cation alloying strategy in 3D perovskites,2DRP perovskites with a binary spacer can promote charge transporting compared to the unary spacer counterparts.Herein,the superior MA-based 2DRP perovskite films with a binary spacer,including 3-guanidinopropanoic acid(GPA)and 4-fluorophenethylamine(FPEA)are realized.These films(GPA_(0.85)FPEA_(0.15))_(2)MA_(4)Pb_5I_(16)show good morphology,large grain size,decreased trap state density,and preferential orientation of the as-prepared film.Accordingly,the present 2DRP-based PSC with the binary spacer achieves a remarkable efficiency of 18.37%with a V_(OC)of1.15 V,a J_(SC)of 20.13 mA cm^(-2),and an FF of 79.23%.To our knowledge,the PCE value should be the highest for binary spacer MA-based 2DRP(n≤5)PSCs to date.Importantly,owing to the hydrophobic fluorine group of FPEA and the enhanced interlayer interaction by FPEA,the unencapsulated 2DRP PSCs based on binary spacers exhibit much excellent humidity stability and thermal stability than the unary spacer counterparts.
基金This work was supported by National Natural Science Foundation of China(U21A20317,51602228,51502207).We also greatly thank the Core Facility of Wuhan University for XRD and XPS analysis and Large-scale Instrument&Equipment Sharing Foundation of Wuhan University.
文摘A highly efficient Ruddlesden-Popper structure anode material with a formula of Sr_(3)Fe_(1.3)Mo_(0.5)Ni_(0.2)O_(7-δ)(RP-SFMN)has been developed for hydrocarbon fueled solid oxide fuel cells(HF-SOFC)application.It is demonstrated that a nanostructured RP-SFMN anode decorated with in-situ exsolved Ni nanoparticles(Ni@RP-SFMN)has been successfully prepared by annealing the anode in reducing atmosphere similar to the operating conditions.The phase compositions,valence states,morphologies,and electrocatalytic activities of RP-SFMN material have been characterized in detail.In addition,the in-situ exsolution mechanism of the metallic Ni phase from the parent oxide is clearly explained by using density function theory calculation.The peak output power density at 800℃ is significantly enhanced from 0.163 to 0.409 W/cm^(2)while the electrode polarization resistance is effectively lowered from 0.96 to 0.30Ωcm^(2)by the substitution of B-site Fe by Ni,which is attributed to the improved electrocatalytic activities induced by the in-situ exsolved Ni nanocatalysts.Moreover,the single cell with RP-SFMN anode exhibits good stability in 3%H_(2)O humidified H_(2)and syngas for 110 and 60 h at 800℃,respectively.Our findings indicate that RP-SFMN is a greatly promising anode candidate of HF-SOFCs due to its good electrochemical performance and stability during the operation.
基金This work was supported by the National Science Foundation of China(NSFC),(Grant No.62022079)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020115).
文摘Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.
基金supported by the US National Science Foundation (DMR-1832809)Idaho National Laboratory,Laboratory Directed Research&Development program under the Department of Energy Idaho Operations Office (DE-AC07-051D14517).
文摘Solid-oxide fuel cells(SOFCs)offer great promise for producing electricity using a wide variety of fuels such as natural gas,coal gas and gasified carbonaceous solids;however,conventional nickel-based anodes face great challenges due to contaminants in readily available fuels,especially sulphur-containing compounds.Thus,the development of new anode materials that can suppress sulphur poisoning is crucial to the realization of fuel-flexible and cost-effective SOFCs.In this work,La_(0.1)Sr_(1.9)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)(LSFNM)and Pr_(0.1)Sr_(1.9)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)(PSFNM)materials have been synthesized using a sol-gel method in air and investigated as anode mater-ials for SOFCs.Metallic nanoparticle-decorated ceramic anodes were obtained by the reduction of LSFNM and PSFNM in H_(2)at 850℃,forming a Ruddlesden-Popper oxide with exsolved FeNi3 bimetallic nanoparticles.The electrochemical performance of the Sr_(2)Fe_(1.4)Ni_(0.1)Mo_(0.5)O_(6-δ)ceramic anode was greatly enhanced by La doping of A-sites,resulting in a 44%decrease in the polarization resistance in reducing atmosphere.The maximum power densities of Sr-and Mg-doped LaGaO_(3)(LSGM)(300μm)electrolyte-supported single cells with LSFNM as the anode reached 1.371 W cm^(-2)in H_(2)and 1.306 W cm^(-2)in 50 ppm H_(2)S-H_(2)at 850℃.Meanwhile,PSFNM showed improved sulphur tolerance,which could be fully recovered after six cycles from H_(2)to 50 ppm H_(2)S-H_(2)operation.This study indicates that LSFNM and PSFNM are promising high-performance anodes for SOFCs.
基金This work was financially supported by the National Key Research and Development Program of China(No.2017YFE0119700)the National Natural Science Found-ation of China(Nos.51961135107,51774034,and 51772026).
文摘Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stability.Two-dimensional(2D)Ruddlesden-Popper(RP)perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations.However,the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells.Moreover,controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult.Herein,we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods.Furthermore,the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.
基金supported in part by the US National Science Foundation(NSF-2055734)a start-up fund from University of Illinois at Urbana-Champaignthe support of a scholarship from the China Scholarship Council(CSC)。
文摘Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)was discovered to be an efficient OER catalyst because of its unique structure,which consists of layers of both rock salt and perovskite phases simultaneously.In this study,we prepared a series of B-site mixed,Ruddlesden-Popper phase of Sr_(2)(Ru_(x)Ir_(1-x))O_(4) and examined their electrocatalytic properties for OER in acidic media.Through partial substitution of Ru in the B-site of Ruddlesden-Popper phase materials,we achieved much enhanced OER performance for this series of Sr_(2)(Ru_(x)Ir_(1-x))O_(4)electrocatalysts,among which Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)exhibited the best catalytic activity with a current density of 8.06 m A/cm^(2) at 1.55 V and a Tafel slope of 47 m V/dec.This current density is three times higher than that of Sr_(2)Ir O_(4).The B-site mixed Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)retained good stability in acidic conditions for>24 h at 10 m A/cm^(2).A range of techniques were used to characterize the crystal and electronic structures of the Sr_(2)(Ru_(x)Ir_(1-x))O_(4)samples.Our data indicate that the improved OER performance can be correlated to the formation of high level of hydroxyl groups and the enhanced overlap between Ir/Ru 4d and O_(2)p orbitals,revealing a new way for the design of efficient OER electrocatalysts by regulating their composition and electronic structures.
基金financially supported by the Natural Science Foundation of China(51972172,61705102,61605073,61935017,91833304,91733302)the National Key R&D Program of China(2017YFB1002900)+3 种基金Projects of International Cooperation and Exchanges NSFC(51811530018)Young 1000 Talents Global Recruitment Program of ChinaJiangsu Specially-Appointed Professor program“Six talent peaks”Project in Jiangsu Province,China。
文摘The crucial component,bulky spacers,in two-dimensional Ruddlesden-Popper(2 DRP)layered tin(Sn)perovskites are highly limited by halide ammonium salts,leading to the insufficient control of complex crystallization process due to the limited interaction between bulky spacers and 2 DRP perovskite frameworks.Here,we report an ionic liquid-bulky spacer,butylammounium acetate(BAAc O),for constructing efficient and stable 2 DRP Sn-based perovskite solar cells(PSCs).In contrast to the traditional halide ammonium bulky spacer,butylammounium iodide(BAI),the Ac O^(-)-functional group in BAAc O has a strong interaction with formamidine ions(FA^(+))and Sn2+.The inter-component interaction allows the formation of controllable intermediates for the favorable growth of smooth,dense,and highly oriented perovskite films.A PSC with power conversion efficiency of 10.36%(7.16%for BAI)is achieved,which is the highest report,along with improved stability with~90%retained after~600 h storage in N_(2) atmosphere without any encapsulation.
基金supported by the National Key Research and Development Program of China(2017YFA0402800)the National Natural Science Foundation of China(51925206,U1932214)。
文摘Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.
基金the Russian Science Foundation(Project 16-13-00112)the budget project#AAAA-A17-117041110045-9 for Boreskov Institute of Catalysis is gratefully acknowledged.
文摘In the field of modern hydrogen energy,obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems.Developing solid oxide fuel cells(SOFC)and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems.In this work,the authors’recent studies in this field are reviewed;the fundamentals of developing materials for SOFC cathodes and oxygen separation membranes’permselective layers based on research of their oxygen mobility and surface reactivity are presented.Ruddlesden-Popper phases Ln_(2-x)Ca_(x)NiO_(4+δ)(LnCNO)and perovskite-fluorite nanocomposites PrNi_(0.5)Co_(0.5)O_(3-δ)-Ce_(0.9)Y_(0.1)O_(2-δ)(PNC-YDC)were studied by isotope exchange of oxygen with C_(18)O_(2)and^(18)O_(2)in flow and closed reactors.For LnCNO a high oxygen mobility was shown(D*~10^(-7)cm^(2)/s at 700℃),being provided by the cooperative mechanism of oxygen migration involving both regular and highly-mobile interstitial oxygen.For PNC-YDC dominated a wide fast diffusion channel via fluorite phase and interphases due to features of the redistribution of cations resulting in superior oxygen mobility(D*~10^(-8)cm^(2)/s at 700℃).After optimization of composition and nanodomain structure of these materials,as cathodes of SOFC they provided a high power density,while for asymmetric supported oxygen separation membranes-a high oxygen permeability.
基金The authors acknowledge the financial support from Macao Science and Technology Development Funds(FDCT-116/2016/A3,FDCT-091/2017/A2,FDCT-014/2017/AMJ)Research Grants(SRG2016-00087-FST,MYRG2018-00148-IAPME)from University of Macao,the Natural Science Foundation of China(91733302,61605073,2015CB932200)the Young 1000 Talents Global Recruitment Program of China.
文摘Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrated.However,the main challenge that currently limits the application of the perovskite solar cells is the long-term stability,which has ambient,thermal,and photo stability weaknesses.
基金the National Research Foundation of Korea grant the Korean government(No.2018R1D1A1B07046937)。
文摘The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well understood.Therefore,the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart,to achieve optimal magnetocaloric performance.A series of self-doped Pr_(1.4+x)Sr_(1.6-x)Mn_(2)O_(7)(0.0≤x≤0.5)Ruddlesden-Popper(R-P)perovskite have been prepared through the solid-state sintering method.With increasing the Pr-stoichiometry,the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite structure.Due to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer(T=304 K)interactions towards the strong three-dimensional(T=308 K)interactions respectively.This series consistently develops thermomagnetic irreversibility in zero-field cooled(ZFC)-field cooled(FC)magnetization,which is indicative of a spin-glass state.The glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the surface.The maximum value of temperature average entropy change(TEC)and adiabatic temperature(ΔT)has enhanced nearly by 4 folds from 0.53 J kg^(-1)K^(-1),0.59 K(for x=0.0)up to 1.85 J kg^(-1)K^(-1),10 K(for x=0.5)at 2.5 T,respectively.Additionally,the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 T.Our findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.
基金financially supported by the National Natural Science Foundation of China under Grant Nos.51772266,51790493 and 51961145105the Natural Science Foundation of Zhejiang Province under Grand No.LY20E020012+1 种基金the National Key R&D Program of China under Grant No.2016YFA0300101the Scientific Research Fund of Zhejiang Provincial Education Department under Grant No.Y201941595.
文摘In the present work,the crystal structure,ferroelectric and dielectric properties of the dense single-phase Li_(2)CaTa_(2)O_(7) ceramics with A-site ordered double-layer Ruddlesden-Popper structures have been investigated by the experiments and first-principles calculations.A polar Pna21 phase was determined by the Rietveld refinement against the X-ray diffraction pattern at room temperature,and it was confirmed by its lowest calculated energy and rigid phonon modes.The ferroelectricity was found by observing the ferroelectric hysteresis loop at room temperature,and its remanent polarization was similar to the value calculated from the Berry phase and Born effective charge approaches.The ferroelectricity is a nonconventional proper one since its polarization is induced from the displacement of oxygen anions instead of tantalum cations based on the individual atomic polarization.A first-order transition from an antiferroelectric to paraelectric phase around 900 K was found by the DSC and variable-temperature dielectric measurements.From the present work,the room-temperature ferroelectricity is experimental confirmed in the present ceramics,inspiring the search for new ferroelectricity in the ceramics with A-site ordered Ruddlesden-Popper structures.
基金National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Grant Nos.2018M3D1A1058793 and 2021R1A3B1068920)the Yonsei Signature Research Cluster Program of 2021(Grant No.2021-22-0002).
文摘Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(<460 nm)PeLEDs still lag far behind their red and green counterparts.Herein,a rapid crystallization method based on hot-antisolvent bathing is proposed for realization of deep-blue PeLEDs.By promoting immediate removal of the precursor solvent from the wet perovskite films,development of the quasi-two-dimensional(2D)Ruddlesden–Popper perovskite(2D-RPP)crystals with n values>3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained successfully.The uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge carriers.Thus,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully demonstrated.The color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.
