Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d...Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.展开更多
A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields...A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields such as thermal barrier coatings,energy storage,dielectric materials,and transparent ceramics.However,there are limited reports on the dielectric properties of A_(2)B_(2)O_(7)high-entropy oxides.Consequently,further investigation is required to understand the polarization mechanisms in high-entropy ceramics and analyze the formation of oxygen vacancies and their influence.In the present study,La_(2)[(TiZrSnHfGe)_((1-2x)5)(NbGa)_(x)]_(2)O_(7)(x=0.129,0.143,0.157,0.171)(LTZSHGNGO)ceramics were synthesized successfully using a conventional solidstate reaction method.Compared withLa_(2)(TiZrSnHfGe)_(2)O_(7)ceramics,LTZSHGNGO demonstrated a nearly 6.7-fold increase in dielectric constant and a 33%reduction in dielectric loss.The incorporation of Nb/Ga enhanced the high-temperature dielectric properties and improved dielectric stability.The exceptional dielectric performance is primarily attributed to the synergistic highentropy effect,while Nb/Ga doping increased the number of oxygen vacancies and generated more defect dipole clusters[Ti^(4+)·e-V_(O)^(**)-Ti^(4+)·e].This study provides novel insights into the dielectric properties of LTZSHGNGO high-entropy ceramics and offers a novel approach to understanding the performance of A_(2)B_(2)O_(7)ceramics.展开更多
High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that ...High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.展开更多
Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition ...Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition and electronic structure.Theoretically,the rapid ion transport and the abundance of surface defects in high-entropy materials suggest a potential for enhancing the performance of composite solid-state electrolytes(CPEs).Herein,using a high-entropy oxide(HEO)filler to assess its potential contributions to CPEs is proposed.The distinctive structural distortions in HEO significantly improve the ionic conductivity(5×10^(−4) S·cm^(−1) at 60℃)and Li-ion transference number(0.57)of CPEs.Furthermore,the enhanced Li-ion transport capability extends the critical current density from 0.6 to 1.5 mA·cm^(−2) in Li/Li symmetric cells.In addition,all-solid-state batteries incorporating the HEO-modified CPEs exhibit superior rate performance and cycling stability.The work will enrich the application of HEOs in CPEs and provide fundamental understanding.展开更多
High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special clas...High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special class of oxides containing five or more different metal cations.The attractive synergistic effect makes HEOs promising energy storage and conversion material.However,at present,the knowledge of HEOs and their practical applications on electrochemistry is still scattered without comprehensive report.In this review,we highlight the preparation methods,common crystal structures and their applications in the field of electrochemistry,which can be divided into two main categories:(1)electrochemical energy storage devices,including supercapacitors,lithium-ion batteries,sodium-ion batteries,and other batteries;(2)electrocatalysis reaction system,including hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and electrocatalytic CO_(2)reduction reaction(CO_(2)RR).Finally,the remaining challenges and prospects in the future are envisioned in the related field,which will help to unlock the mysteries of HEOs for energy storage and conversion.展开更多
03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hin...03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.展开更多
Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SO...Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.展开更多
As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise beca...As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise because of their high energy conversion efficiency and wide range of applications.Highentropy materials(HEMs),a novel class of materials comprising several principal elements,have attracted significant interest within the materials science and energy sectors.Their distinctive structural features and adaptable functional properties offer immense potential for innovation across various applications.This review systematically covers the basic concepts,crystal structures,element selection,and major synthesis strategies of HEMs,and explores in detail the specific applications of these materials in SOCs,including its potential as air electrodes,fuel electrodes,electrolytes,and interconnects(including barrier coatings).By analyzing existing studies,this review reveals the significant advantages of HEMs in enhancing the performance,anti-poisoning,and stability of SOCs;highlights the key areas and challenges for future research;and looks into possible future directions.展开更多
Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor...Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice distortion.Here,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced HEOs.Among the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic interactions.Particularly,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 K.Moreover,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκefficiently.This work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.展开更多
Solid oxide cells(SOCs),which include solid oxide fuel cells(SOFCs),symmetrical solid oxide cells(S-SOCs),and reversible solid oxide cells(R-SOCs),are considered key technologies for driving low-carbon and green revol...Solid oxide cells(SOCs),which include solid oxide fuel cells(SOFCs),symmetrical solid oxide cells(S-SOCs),and reversible solid oxide cells(R-SOCs),are considered key technologies for driving low-carbon and green revolution in the energy sector.Because of their clean,low-cost,and high-efficiency characteristics,SOCs have great potential for energy conversion and storage.However,the further development of SOC technologies faces challenges,such as a lack of long-term operational stability of the cell system,high material cost under high-temperature operating conditions,and limited catalytic effects at low temperatures.Recently,high-entropy materials(HEMs)have demonstrated excellent performance and wide application prospects in catalytic reactions,energy storage,supercapacitors,and other fields owing to their unique atomic arrangement and the four core effects(high mixed entropy stabilization effect,sluggish dif-fusion effect,lattice distortion effect,and“cocktail”effect).HEMs provide a new perspective for solving the aforementioned problems in the field of SOCs.This comprehensive review summarizes the applications of HEMs in the three fundamental components of SOCs:elec-trodes,electrolytes,and interconnects,focusing on the role of HEMs in enhancing catalytic activity and conductivity while mitigating harmful gas poisoning.In addition,this review proposes possible development directions for HEMs in SOCs based on the current re-search progress,providing valuable reference for high-entropy designs aimed at further enhancing the performance of SOCs.展开更多
Developing highly active and stable air electrodes remains challenging for reversible solid oxide cells(R-SOCs).Herein,we re-port an A-site high-entropy engineered perovskite oxide,La_(0.2)Pr_(0.2)Nd_(0.2)Ba_(0.2)Sr_(...Developing highly active and stable air electrodes remains challenging for reversible solid oxide cells(R-SOCs).Herein,we re-port an A-site high-entropy engineered perovskite oxide,La_(0.2)Pr_(0.2)Nd_(0.2)Ba_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF),and its electrocatalytic activity and stability property are systematically probed for tubular R-SOCs.The HE-LSCF air electrode exhibits excellent oxygen reduction reac-tion(ORR)activity with a low polarization resistance of 0.042Ω·cm^(2)at 700℃,which is much lower than that of La0.6Sr0.4Co_(0.8)Fe_(0.2)O_(3−δ)(LSCF),indicating the excellent catalytic activity of HE-LSCF.Meanwhile,the tubular R-SOCs with HE-LSCF shows a high peak power density of 1.18 W·cm^(−2)in the fuel cell mode and a promising electrolysis current density of−0.52 A·cm^(−2)at 1.5 V in the electrolysis mode with H_(2)(~10%H_(2)O)atmosphere at 700℃.More importantly,the tubular R-SOCs with HE-LSCF shows favorable stability under 180 h reversible cycling test.Our results show the high-entropy design can significantly enhance the activity and robustness of LSCF electrode for tubular R-SOCs.展开更多
Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose har...Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation ...The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.展开更多
In the paper,we report a highly robust and porous bimetallic Ti-MOF(designated Mg_(2)Ti-ABTC)by utiliz-ing a trinuclear[Mg_(2)TiO(COO)_(6)]cluster and a tetradentate H_(4)ABTC(3,3′,5,5′-azobenzene tetracarboxylic ac...In the paper,we report a highly robust and porous bimetallic Ti-MOF(designated Mg_(2)Ti-ABTC)by utiliz-ing a trinuclear[Mg_(2)TiO(COO)_(6)]cluster and a tetradentate H_(4)ABTC(3,3′,5,5′-azobenzene tetracarboxylic acid)ligand.Mg_(2)Ti-ABTC exhibited permanent porosity for N_(2),CO_(2),CH_(4),C_(2)H_(2),C_(2)H_(4),and C_(2)H_(6)gas adsorption.Further-more,Mg_(2)Ti-ABTC exhibited outstanding photocatalytic activity in the oxidation of aromatic sulfides to the corre-sponding sulfoxides under ambient air conditions.Mechanism studies reveal that photoinduced holes(h^(+)),the super-oxide radical(·O_(2)^(-)),and singlet oxygen(^(1)O_(2))are pivotal species involved in the photocatalytic oxidation reaction.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
Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs of...Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.展开更多
The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the ...The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
All-perovskite tandem solar cells(ATSCs) have the potential to surpass the Shockley-Queisser efficiency limit of conventional single-junction devices. However, the performance and stability of mixed tin–lead(Sn–Pb) ...All-perovskite tandem solar cells(ATSCs) have the potential to surpass the Shockley-Queisser efficiency limit of conventional single-junction devices. However, the performance and stability of mixed tin–lead(Sn–Pb) perovskite solar cells(PSCs), which are crucial components of ATSCs, are much lower than those of lead-based perovskites. The primary challenges include the high crystallization rate of perovskite materials and the susceptibility of Sn^(2+) oxidation, which leads to rough morphology and unfavorable p-type self-doping. To address these issues, we introduced ethylhydrazine oxalate(EDO) at the perovskite interface, which effectively inhibits the oxidation of Sn^(2+) and simultaneously enhances the crystallinity of the perovskite. Consequently, the EDO-modified mixed tin-lead PSCs reached a power conversion efficiency(PCE) of 21.96% with high reproducibility. We further achieved a 27.58% efficient ATSCs by using EDO as interfacial passivator in the Sn-Pb PSCs.展开更多
基金supported by the National Natural Science Foundation of China(No.21805018)by Sichuan Science and Technology Program(Nos.2022ZHCG0018,2023NSFSC0117 and 2023ZHCG0060)Yibin Science and Technology Program(No.2022JB005)and China Postdoctoral Science Foundation(No.2022M722704).
文摘Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.
基金financially supported by the National Natural Science Foundation of China(No.52201173)the S&T Program of Hebei(No.22567627H)+3 种基金the Natural Science Foundation of Hebei Province(No.E2021501017)Henan key Laboratory of Aeronautical Materials and Application Technology Open fund(No.ZHKF-230113)Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021301)the Fundamental Research Funds for the Central Universities(No.2024GFYD002,N2323021)
文摘A_(2)B_(2)O_(7)high-entropy oxides are ceramic materials characterized by diverse compositions,strong structural inclusivity,and a broad range of potential applications.These materials hold significant value in fields such as thermal barrier coatings,energy storage,dielectric materials,and transparent ceramics.However,there are limited reports on the dielectric properties of A_(2)B_(2)O_(7)high-entropy oxides.Consequently,further investigation is required to understand the polarization mechanisms in high-entropy ceramics and analyze the formation of oxygen vacancies and their influence.In the present study,La_(2)[(TiZrSnHfGe)_((1-2x)5)(NbGa)_(x)]_(2)O_(7)(x=0.129,0.143,0.157,0.171)(LTZSHGNGO)ceramics were synthesized successfully using a conventional solidstate reaction method.Compared withLa_(2)(TiZrSnHfGe)_(2)O_(7)ceramics,LTZSHGNGO demonstrated a nearly 6.7-fold increase in dielectric constant and a 33%reduction in dielectric loss.The incorporation of Nb/Ga enhanced the high-temperature dielectric properties and improved dielectric stability.The exceptional dielectric performance is primarily attributed to the synergistic highentropy effect,while Nb/Ga doping increased the number of oxygen vacancies and generated more defect dipole clusters[Ti^(4+)·e-V_(O)^(**)-Ti^(4+)·e].This study provides novel insights into the dielectric properties of LTZSHGNGO high-entropy ceramics and offers a novel approach to understanding the performance of A_(2)B_(2)O_(7)ceramics.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(No.52021004)the Funds for Chongqing Talents Plan(No.CQYC2021059563)+1 种基金the Fundamental Research Funds for the Central Universities(No.2021CDJQY-027)the National Natural Science Foundation of China(No.52206089).
文摘High-entropy materials(HEMs),which are typically composed of five or more elements in near-equimolar ratios with concentrations ranging from 5%to 35%,have distinct elemental compositions and geometric properties that allow for the development of advanced electrocatalysts for renewable energy conversion systems.The highentropy effect,crystal dislocations,cocktail effect,and slow diffusion in high-entropy layered double hydroxides(HE-LDHs)and amorphous materials(HE-AMs)have all been shown to boost electrocatalytic water oxidation performance significantly.These materials exhibit remarkable activity and stability in both alkaline and acidic conditions.HE-AMs,in particular,benefit from a variety of defects,including coordinatively unsaturated sites and loosely connected atoms,which are critical to their improved catalytic capabilities.HEMs engineering and precise nanostructure control can address the low intrinsic activity,restricted active sites,and poor conductivity of binary and ternary amorphous and LDH catalysts.This study discusses current advances in HE-LDHs and HE-AMs for water electrolysis,including synthesis methods,structural features,active site identification by DFT calculations,and their applications in water electrocatalysis.The presentation also covers potential problems and future directions for developing these materials in energy conversion device systems.
基金supported by the National Natural Science Foundation of China(No.52002094)Shenzhen Science and Technology Program(Nos.JCYJ20210324121411031,JSGG202108021253804014 and RCBS20210706092218040)Shenzhen Steady Support Plan(Nos.GXWD20221030205923001 and GXWD20201230155427003-20200824103000001).
文摘Recently,high-entropy materials are attracting enormous attention in battery applications,encompassing both electrode materials and solid electrolytes,due to the pliability and diversification in material composition and electronic structure.Theoretically,the rapid ion transport and the abundance of surface defects in high-entropy materials suggest a potential for enhancing the performance of composite solid-state electrolytes(CPEs).Herein,using a high-entropy oxide(HEO)filler to assess its potential contributions to CPEs is proposed.The distinctive structural distortions in HEO significantly improve the ionic conductivity(5×10^(−4) S·cm^(−1) at 60℃)and Li-ion transference number(0.57)of CPEs.Furthermore,the enhanced Li-ion transport capability extends the critical current density from 0.6 to 1.5 mA·cm^(−2) in Li/Li symmetric cells.In addition,all-solid-state batteries incorporating the HEO-modified CPEs exhibit superior rate performance and cycling stability.The work will enrich the application of HEOs in CPEs and provide fundamental understanding.
基金the Macao Science and Technology Development Fund(FDCT)for funding(FDCT-MOST joint project nos.0026/2022/AMJ,0098/2020/A2,and 006/2022/ALC of the Macao Centre for Research and Development in Advanced Materials(2022-2024))the Natural Science Foundation of Guangdong Province(No.2023A1515010765)+4 种基金the Shenzhen-Hong Kong-Macao Science and Technology Plan Project(Category C)(No.SGDX20220530111004028)the Science and Technology Program of Guangdong Province of China(No.2023A0505030001)the National Natural Science Foundation of China(No.52102264)the Leading Edge Technology of Jiangsu Province(No.BK20220009)the Macao Young Scholars Program(No.AM2022009).
文摘High-entropy oxides(HEOs)have received considerable attention in the past few years due to their unique high configurational entropy and ideal elemental adjustability.HEOs are generally considered to be a special class of oxides containing five or more different metal cations.The attractive synergistic effect makes HEOs promising energy storage and conversion material.However,at present,the knowledge of HEOs and their practical applications on electrochemistry is still scattered without comprehensive report.In this review,we highlight the preparation methods,common crystal structures and their applications in the field of electrochemistry,which can be divided into two main categories:(1)electrochemical energy storage devices,including supercapacitors,lithium-ion batteries,sodium-ion batteries,and other batteries;(2)electrocatalysis reaction system,including hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and electrocatalytic CO_(2)reduction reaction(CO_(2)RR).Finally,the remaining challenges and prospects in the future are envisioned in the related field,which will help to unlock the mysteries of HEOs for energy storage and conversion.
基金supported by the Science and technology plan project of Yulin(2023-CXY-193)the Project funded by Shaanxi Postdoctoral Science Foundation(2023BSHEDZZ274)+2 种基金the Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0588,Z20210201)the Science and technology plan project of Beilin(GX2319)the Science and technology plan project of Ankang(AK2023-GY-08)。
文摘03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.
基金financial support from the JSPS KAKENHI Grant-in-Aid for Scientific Research(B),No.21H02035KAKENHI Grant-in-Aid for Challenging Research(Exploratory),No.21K19017+2 种基金KAKENHI Grant-in-Aid for Transformative Research Areas(B),No.21H05100National Natural Science Foundation of China,No.22409033 and No.22409035Basic and Applied Basic Research Foundation of Guangdong Province,No.2022A1515110470.
文摘Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.
基金supported by the National Key R&D Program of China(2022YFB4004000)National Natural Science Foundation of China(U24A20542,52472210,22279057)+3 种基金Natural Science Foundation of Jiangsu Province(BK20221312)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_1465)Cultivation Program for the Excellent Doctoral Dissertation of Nanjing Tech University(2023-09)the grant of Hydrogen Energy Laboratory(No.FEUZ-2024-0009)。
文摘As global energy demand increases and environmental standards tighten,the development of efficient,eco-friendly energy conversion and storage technologies becomes crucial.Solid oxide cells(SOCs)show great promise because of their high energy conversion efficiency and wide range of applications.Highentropy materials(HEMs),a novel class of materials comprising several principal elements,have attracted significant interest within the materials science and energy sectors.Their distinctive structural features and adaptable functional properties offer immense potential for innovation across various applications.This review systematically covers the basic concepts,crystal structures,element selection,and major synthesis strategies of HEMs,and explores in detail the specific applications of these materials in SOCs,including its potential as air electrodes,fuel electrodes,electrolytes,and interconnects(including barrier coatings).By analyzing existing studies,this review reveals the significant advantages of HEMs in enhancing the performance,anti-poisoning,and stability of SOCs;highlights the key areas and challenges for future research;and looks into possible future directions.
基金supported by National defense ba-sic scientific research(Grant Nos.2022-JCKY-JJ-1086 and 211-CXCY-N103-03-04-00).
文摘Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced materials.The instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice distortion.Here,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced HEOs.Among the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic interactions.Particularly,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 K.Moreover,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκefficiently.This work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.
基金supported by the Industrial Foresight Projects and Common Key Technologies of Zhenjiang(No.GY2024028)The authors also acknowledged the support of the Marine Equipment and Technology Institute,Jiangsu University of Science and Technology(No.XTCX202404).
文摘Solid oxide cells(SOCs),which include solid oxide fuel cells(SOFCs),symmetrical solid oxide cells(S-SOCs),and reversible solid oxide cells(R-SOCs),are considered key technologies for driving low-carbon and green revolution in the energy sector.Because of their clean,low-cost,and high-efficiency characteristics,SOCs have great potential for energy conversion and storage.However,the further development of SOC technologies faces challenges,such as a lack of long-term operational stability of the cell system,high material cost under high-temperature operating conditions,and limited catalytic effects at low temperatures.Recently,high-entropy materials(HEMs)have demonstrated excellent performance and wide application prospects in catalytic reactions,energy storage,supercapacitors,and other fields owing to their unique atomic arrangement and the four core effects(high mixed entropy stabilization effect,sluggish dif-fusion effect,lattice distortion effect,and“cocktail”effect).HEMs provide a new perspective for solving the aforementioned problems in the field of SOCs.This comprehensive review summarizes the applications of HEMs in the three fundamental components of SOCs:elec-trodes,electrolytes,and interconnects,focusing on the role of HEMs in enhancing catalytic activity and conductivity while mitigating harmful gas poisoning.In addition,this review proposes possible development directions for HEMs in SOCs based on the current re-search progress,providing valuable reference for high-entropy designs aimed at further enhancing the performance of SOCs.
基金support provided by the National Key R&D Program of China(No.2024YFE0101500)the National Natural Science Foundation of China(No.52272257)the Natural Science Foundation of Jiangsu Province(No.BK20240109).
文摘Developing highly active and stable air electrodes remains challenging for reversible solid oxide cells(R-SOCs).Herein,we re-port an A-site high-entropy engineered perovskite oxide,La_(0.2)Pr_(0.2)Nd_(0.2)Ba_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF),and its electrocatalytic activity and stability property are systematically probed for tubular R-SOCs.The HE-LSCF air electrode exhibits excellent oxygen reduction reac-tion(ORR)activity with a low polarization resistance of 0.042Ω·cm^(2)at 700℃,which is much lower than that of La0.6Sr0.4Co_(0.8)Fe_(0.2)O_(3−δ)(LSCF),indicating the excellent catalytic activity of HE-LSCF.Meanwhile,the tubular R-SOCs with HE-LSCF shows a high peak power density of 1.18 W·cm^(−2)in the fuel cell mode and a promising electrolysis current density of−0.52 A·cm^(−2)at 1.5 V in the electrolysis mode with H_(2)(~10%H_(2)O)atmosphere at 700℃.More importantly,the tubular R-SOCs with HE-LSCF shows favorable stability under 180 h reversible cycling test.Our results show the high-entropy design can significantly enhance the activity and robustness of LSCF electrode for tubular R-SOCs.
基金National Natural Science Foundation of China(52376076)Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province(2023CL13)Laiwu Vocational and Technical College Teachers Research Fund(2023jsky05)。
文摘Powder metallurgy was used to fabricate TiC-NiCr cermets and the oxidation behavior at 900℃ was investigated.Results reveal that TiC-NiCr cermets have uniform structures with excellent mechanical properties,whose hardness is 65 HRC and flexural strength is 1450 MPa.The high-temperature oxidation mechanism of TiC-based cermets was investigated through an X-ray diffractometer and scanning electron microscope.The added elements Ni and Cr along with their solid solutions not only bond with the hard phase TiC to ensure the physical performance of the cermet,but also impede the internal diffusion during oxidation by forming a dense composite oxide layer,thereby enhancing the oxidation resistance.The TiC-NiCr cermet exhibits a dense protective oxide layer at 900℃ and can endure continuous oxidation for approximately 1000 h.A methodology for fabricating TiC-NiCr metal matrix composites is proposed,and their oxidation resistance is evaluated,providing a theoretical and practical basis for simultaneously enhancing the mechanical properties and oxidation resistance and reducing production costs.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
基金supported by Natural Science Foundation of Shandong Province(ZR2021MB075)Fundamental Research Funds for the Central Universities,Ocean University of China(202461021).
文摘The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.
文摘In the paper,we report a highly robust and porous bimetallic Ti-MOF(designated Mg_(2)Ti-ABTC)by utiliz-ing a trinuclear[Mg_(2)TiO(COO)_(6)]cluster and a tetradentate H_(4)ABTC(3,3′,5,5′-azobenzene tetracarboxylic acid)ligand.Mg_(2)Ti-ABTC exhibited permanent porosity for N_(2),CO_(2),CH_(4),C_(2)H_(2),C_(2)H_(4),and C_(2)H_(6)gas adsorption.Further-more,Mg_(2)Ti-ABTC exhibited outstanding photocatalytic activity in the oxidation of aromatic sulfides to the corre-sponding sulfoxides under ambient air conditions.Mechanism studies reveal that photoinduced holes(h^(+)),the super-oxide radical(·O_(2)^(-)),and singlet oxygen(^(1)O_(2))are pivotal species involved in the photocatalytic oxidation reaction.
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.
文摘Introduction High-entropy oxides(HEOs)have attracted much attention in the field of electrochemistry due to their distinctive structural characteristics and unique properties.The multiple-principal elements in HEOs offer the multiple redox pairs and multiple possible active sites,which can enhance the energy storage capacity and the electrocatalytic performance.Although the notable progress is achieved in the development of HEOs electrodes,their electrochemical properties should be further improved to meet the requirements of high-performance supercapacitors and OER electrocatalysts.The abundant active sites for the Faradic redox reactions and short pathways for charge transportation could be constructed through the design of novel HEOs with advanced microstructures,thus improving the electrochemical properties.As advanced microstructures,a hollow structure has a great promise for energy storage and conversion because it can provide more accessible storage sites,more catalytic centers and a larger electrode/electrolyte contact area.It is thus expected that the construction of hollow structure is an alternative route to significantly promote the electrochemical properties of HEOs electrode materials.However,it is difficult to prepare the HEOs with a hollow structure due to the complexity of the high-entropy system.In this work,a hollow spherical high-entropy perovskite oxide of La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)(HS-HEPs)was prepared by microwave solvothermal process and subsequent calcination treatment.The as-prepared HS-HEPs exhibited the excellent electrochemical performance when used as an electrode material for supercapacitors and OER electrocatalysts due to the advantages resulted from the combination of high-entropy perovskite and special hollow structure.Methods HS-HEPs were prepared by microwave solvothermal process and subsequent calcination treatment.Typically,0.134 mmol Cr(NO_(3))_(3)·6H_(2)O,0.134 mmol Mn(NO_(3))_(2)·4H_(2)O,0.134 mmol Fe(NO_(3))_(3)·9H_(2)O,0.134 mmol Ni(NO_(3))_(2)·6H_(2)O,0.134 mmol Cu(NO_(3))_(2)·3H_(2)O,and 0.5 mmol La(NO_(3))_(3)·6H_(2)O were dissolved in 30 mL ethanol under stirring for 1 h to obtain the homogeneous solution.Afterwards,60 mg of carbon spheres were added in the solution under ultrasonic treatment for 30 min.The resulting mixture was transferred to a 50 mL microwave digestion vessel.The vessel was heated in a microwave oven at a power of 210 W for 10 min.Subsequently,the obtained mixture was centrifuged,washed with deionized water,and dried in a vacuum drying oven at 70℃for 12 h.Finally,the obtained precursor powder was calcinated in a tube furnace with a heating rate of 3℃/min at 650℃for 2 h to acquire HS-HEPs.The crystalline structure of the sample was determined by X-ray diffraction(XRD,D8 Davinci,Bruker Co.,Germany).The morphology and microstructure of sample were characterized by field-emission scanning electron microscopy(FESEM,S-4800,Hitachi Co.Ltd.,Japan)equipped with energy dispersive X-ray spectroscopy(EDS)and transmission electron microscopy(TEM,2100F,JEOL Co.,Japan).The X-ray photoelectron spectra were obtained by a X-ray photoelectron spectrometry(XPS,ESCALab 250,Thermo VG Co.,USA).The supercapacitor and OER performance of the sample were measured on a CHI 660E electrochemical workstation(Shanghai Chenhua Instrument Co.,China).Results and discussion The as-prepared samples display a cubic perovskite crystalline structure and a hollow sphere morphology.According to the XPS analysis,the variable oxidation states of Cr,Fe and Mn present in the HS-HEPs,which benefits the Faradaic redox reactions and increases the capacitance.In addition,the existence of high concentration of oxygen vacancies in HS-HEPs is beneficial to enhancing the capacitance and OER activity.Based on the GCD curve,the specific capacitance of HS-HEPs is estimated to be 406 F/g at 1 A/g.After GCD cycles of 5000 at a current density of 5 A/g,65%capacitance is retained,implying a good long-term electrochemical stability.An asymmetric supercapacitor device(HS-HEPs//AC)with a two electrode configuration is assembled.A maximum energy density of 39.4 W·h/kg is achieved at power density of 746 W/kg.The OER activity of HS-HEPs is evaluated by a linear sweep voltammetry(LSV)polarization curve in 1 mol/L KOH aqueous solution using a standard three-electrode system.The overpotential of HS-HEPs is identified as 347 mV versus RHE for achieving a current density of 10 mA/cm^(2),which is smaller than that of commercial IrO2(372 mV).The HS-HEPs possess the excellent electrochemical performance,which can be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Conclusions High-entropy La(Cr_(0.2)Mn_(0.2)Fe_(0.2)Ni_(0.2)Cu_(0.2))O_(3)hollow spheres with a perovskite crystalline structure were prepared by microwave solvothermal process and subsequent calcination treatment.The HS-HEPs possessed the excellent electrochemical performance,which could be ascribed to the high specific surface area,abundant active sites,and high oxygen vacancy content,resulting from the combination of high-entropy perovskite and special hollow structure.Based on the electrochemical performance,HS-HEPs could be used as supercapacitor electrode material and OER electrocatalysts.This work could provide a strategy to design and prepare high-entropy oxides with a hollow sphere structure,having promising applications in energy storage and conversion.
基金supported by the National Key R&D Program of China(No.2022YFB2404400)the National Natural Science Foundation of China(Nos.U23A20577,52372168,92263206 and 21975006)+1 种基金the“The Youth Beijing Scholars program”(No.PXM2021_014204_000023)the Beijing Natural Science Foundation(Nos.2222001 and KM202110005009).
文摘The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
基金financially supported by National Key R&D Program of China (2025YFE0100300)the National Natural Science Foundation of China (52202293 and 52330004)the Fundamental Research Funds for the Central Universities (WUT: 2023IVA075 and 2023IVB009)。
文摘All-perovskite tandem solar cells(ATSCs) have the potential to surpass the Shockley-Queisser efficiency limit of conventional single-junction devices. However, the performance and stability of mixed tin–lead(Sn–Pb) perovskite solar cells(PSCs), which are crucial components of ATSCs, are much lower than those of lead-based perovskites. The primary challenges include the high crystallization rate of perovskite materials and the susceptibility of Sn^(2+) oxidation, which leads to rough morphology and unfavorable p-type self-doping. To address these issues, we introduced ethylhydrazine oxalate(EDO) at the perovskite interface, which effectively inhibits the oxidation of Sn^(2+) and simultaneously enhances the crystallinity of the perovskite. Consequently, the EDO-modified mixed tin-lead PSCs reached a power conversion efficiency(PCE) of 21.96% with high reproducibility. We further achieved a 27.58% efficient ATSCs by using EDO as interfacial passivator in the Sn-Pb PSCs.
