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| 1 | Nanozymes Inspired by Natural Enzymes显示文摘CONSPECTUS:Nanozymes,nanomaterials with enzyme-like activities with high structural stability,adjustable catalytic activity,functional diversity,recyclability,and feasibility in large-scale preparation,have become a hot spot in the field of artificial enzymes in recent years and are expected to become potential surrogates and competitors for natural enzymes in practical applications.With the development of in-depth research and a wide range of application requirements,creating nanozymes with catalytic performance comparable to or even surpassing that of natural enzymes has been the key research topic in this field.Most of the nanozymes reported in the past were obtained based on random synthesis and screening,for which the catalytic efficiency is far inferior to that of natural enzymes.Natural enzymes that have evolved over hundreds of millions of years have developed a lot of high-efficiency catalysis know-how hidden in their structural features.To create highly active nanozymes,we assumed that there is a general structure−activity relationship between nanozymes and natural enzymes and proposed the nanozyme optimization strategy by grafting the catalytic principles of natural enzymes into the rational design of nanozymes.On the basis of this bioinspired strategy,a series of nanozymes that exhibit similar catalytic activities that are closer to or even beyond those of natural enzymes have been successfully synthesized.By now,rationally designed high-activity bioinspired nanozymes have become a hot topic in the current research on nanozymes.In this Account,we focus on recent representative research progress in the systemic design and construction of bioinspired nanozymes and are devoted to introducing strategic concepts in the bioinspired optimization of nanozymes.We show that the de novo design of nanozymes by simulating the amino acid microenvironment and using metal-free architecture and the coordination structure of metal active sites in natural enzymes is an effective strategy for significantly improving the catalytic performance of nanozymes.A future perspective of the challenges and countermeasures of bioinspired nanozymes is proposed on the basis of these achievements.We hope that the biologically inspired perception will arouse widespread interest in fundamental research and practical applications as well as provide inspiration for the rational design of nanozymes. | Ruofei Zhang Xiyun Yan Kelong Fan | 2021 | Accounts of Materials Research2021，2，7： | 8 |
| 2 | Structural Engineering of Eu^2+-Doped Silicates Phosphors for LED Applications显示文摘CONSPECTUS:Phosphor-converted light-emitting diodes(pc-LEDs)are of great importance for their applications in solid-state lighting,backlit display,and near-infrared detection light source.Herein,the main challenges for these emergent pc-LEDs are to achieve full-spectrum lighting,wide color gamut display and broadband high efficiency near-infrared emission,respectively,which depends on the luminescence properties of phosphors used.Owing to the unique 4f-5d transition,Eu^2+is one of the most commonly used activators in luminescent materials for pc-LEDs,and Eu^2+-doped earth-abundant silicates phosphors exhibit outstanding luminescence properties,including multicolor emission,adjustable bandwidth,excellent thermal stability as well as high luminescence efficiency.These attributes motivate scientists to find Eu^2+-doped silicates phosphors that can practically meet the various LED application requirements.Since the traditional trial and error exploration is time-consuming and not necessarily successful,it is necessary to find reliable structural engineering strategies to discover new phosphor systems and also realize purposeful photoluminescence tuning.The adjustable 4f-5d electronic transitions of Eu^2+,the variable crystal structures of the silicate hosts and their coupling effect simultaneously account for the targeted luminescence behaviors and their precise emission color tuning.Thus,we aim at developing Eu^2+-doped silicate phosphors that can solve the application challenges through a comprehensive understanding of Eu^2+photoluminescence mechanism and the structure−property relationships.In this Account,we first illustrate the luminescence theory of Eu^2+in inorganic solids and summarize the research results of the effect originated from centroid shift,crystal field splitting,Stokes shift,and emission bandwidth.On the basis of the factors dominating the variation of luminescence characteristics,several structural strategies to manipulate Eu^2+emission in silicates are proposed,including(1)modify the chemical composition and crystal structure by various substitutions,(2)choose or change a suitable crystallographic site for Eu^2+and(3)control crystalline phase transition by external factors.Meanwhile,we briefly introduce the photoluminescence behaviors of Eu^2+in different silicates controlled by these structural engineering strategies.Second,we outline our recent research progress on blue LED pumped Eu^2+-doped silicate phosphors with emphasis on the design principle and the relationship between the structure and luminescence.The state-of-the-art LED application including full spectrum solid-state lighting,wide color gamut display and near-infrared night-vision technologies are introduced.Finally,we proposed the future research opportunities and challenges.The development of these Eu^2+-doped silicate phosphors exhibiting excellent luminescence performance is highly inspiring,and we expect this Account can be helpful for controlling the photoluminescence by theory-structure−property relationships and guide scientists discover the next generation of Eu^2+-doped phosphors for emerging applications. | Ming Zhao Qinyuan Zhang Zhiguo Xia | 2020 | Accounts of Materials Research2020，1，2： | 7 |
| 3 | PGM-Free Oxygen-Reduction Catalyst Development for Proton-Exchange Membrane Fuel Cells:Challenges,Solutions,and Promises显示文摘CONSPECTUS:Proton-exchange membrane fuel cells(PEMFCs)are efficient and clean hydrogen energy technologies for transportation and stationary applications.Highly active and durable low-cost cathode catalysts for the oxygen-reduction reaction(ORR)under challenging acidic environments are desperately needed to address the cost and durability issues of PEMFCs.The most promising platinum group metal(PGM)-free catalysts for the ORR in acidic media are atomically dispersed and nitrogencoordinated metal site catalysts denoted as M−N−C,M=Fe,Co,or Mn.Due to significant efforts in the past few decades,these catalysts have demonstrated much-improved ORR activity and promising initial fuel cell performance approaching traditional Pt/C catalysts.However,the insufficient long-term stability(up to 5000 h)under PEMFC operation represents a primary technical barrier to making current PGM-free catalysts less viable yet in PEMFCs.In this Account,we highlight recent advances in synthesizing efficient PGM-free catalysts for the ORR in PEMFCs,emphasizing effective strategies to improve mass and intrinsic activity and the possible degradation mechanisms.In particular,a chemical doping method based on the zeolitic imidazolate framework(ZIF)-8 represents the key to developing efficient M−N−C catalysts containing atomically dispersed and nitrogen-coordinated single metal active sites(i.e.,MN_(4)).The newly acquired understanding of the formation mechanism of MN_(4)active sites during the thermal activation and its correlation to catalytic properties guide the rational catalyst design rather than relying on current trial-and-error approaches.Considerable efforts have further been invested in increasing the active site density and enhancing intrinsic activity by regulating carbon-phase structures and the local coordination environment.These highly active catalysts usually suffer from significant activity loss during the ORR.Therefore,breaking the activity−stability trade-off is the key to simultaneously achieving activity and stability in one catalyst,which is discussed on the basis of our recent successes in regulating local carbon structures surrounding active single metal sites.Significant research efforts toward understanding the degradation mechanisms and improving the lifetime of PGM-free catalysts are still crucial for viable applications in the future.Novel electrode designing strategies are needed to translate the PGM-free catalysts’ORR activity to solid-state electrolyte-based membrane electrode assemblies(MEAs)with robust three-phase(i.e.,gas−liquid−solid)interfaces for efficient charge and mass transports for performance improvement.On the basis of our effort at the University at Buffalo supported by ElectroCat Consortium associated with U.S.DOE’s Hydrogen and Fuel Cell Technologies Office,we provide a perspective on PGM-free cathode catalysts concerning remaining bottlenecks and future opportunities,aiming to inspire the community in both mechanistic understanding and technological development. | Yanghua He Gang Wu | 2022 | Accounts of Materials Research2022，3，2： | 5 |
| 4 | Microenvironment Modulation in Metal−Organic Framework-Based Catalysis显示文摘CONSPECTUS:The fine design and regulation of catalysts play critical roles in the development of catalysis.The microenvironment,which gives rise to unique spatial structures and electronic properties around catalytic sites,has been proven to dramatically regulate catalytic behavior in enzymes and homogeneous catalysis.However,understanding the microenvironment modulation(MEM)of catalytic sites remains challenging and very limited in heterogeneous catalysis mainly due to the lack of structural precision and/or tailorability of traditional solid catalysts.Among diverse materials,metal−organic frameworks(MOFs),a class of porous crystalline solids,have been intensively studied as heterogeneous catalysts in recent years.The atomically precise and well tunable structures of MOFs make them an ideal platform for rationally regulating the microenvironment surrounding catalytic sites.Accordingly,their well-defined structures hold great promise for elucidating how the microenvironment modulation affects the resulting catalytic performance.Nevertheless,the investigations of accurate control over the microenvironment of catalytic sites in MOFs for modulated catalysis are still very limited.Therefore,it is of great importance to summarize the related results and provide in-depth insights into microenvironment modulation in MOF-based catalysis,accelerating the future development of this emerging research topic.In this Account,we have presented a summary of our recent attempts to optimize the catalytic performance of MOF-based materials via microenvironment modulation.In view of the unique component and structural advantages of MOFs,we deliver the general fundamentals for rational control over the microenvironment in MOF-based catalysis.Initially,the great opportunities brought about by MOFs for accurate control over microenvironment engineering,including the origin of abundant active sites,flexible regulation strategies,and well-defined structure,are introduced in detail.In the next section,we focus on the specific strategies of microenvironment modulation in MOF-based catalysis,which dominate the molecular/electron-transfer process and regulate the intrinsic activity of catalytic sites.Meanwhile,the related chemical basis and underlying structure−property relationship behind the enhanced catalytic performance will be highlighted.Finally,the major challenges and future outlooks on the microenvironment modulation in MOF-based catalysis will be further discussed.It is expected that this Account would provide an understanding of the importance of microenvironment modulation around catalytic sites in MOF-based catalysts and afford significant inspiration toward enhanced performance by microenvironment engineering in heterogeneous catalysis. | Long Jiao Jingxue Wang Hai-Long Jiang | 2021 | Accounts of Materials Research2021，2，5： | 5 |
| 5 | Engineering Covalent Organic Framework Membranes显示文摘CONSPECTUS:Membrane technology plays an increasingly important role for sustainable development of our society owing to its huge capability to tackle the energy crisis,water scarcity,environmental pollution,and carbon neutrality.To fully unlock the potential of membranes,it is in high demand to develop advanced membrane materials that significantly outperform conventional polymer membrane materials in separation performance and longterm stability.The emergent covalent organic frameworks(COFs)have been deemed as potent membrane materials because of their unique structure and properties in comparison with polymers,zeolites,and metal organic frameworks(MOFs).(i)First,the highly tunable and ordered crystalline pore structure,high porosity,and excellent stability render COFs an ideal membrane material.COFs are more stable than MOFs and,in some cases,are even more stable than zeolite.Moreover,it is easier to introduce functional groups into the COF nanochannels compared with zeolite and MOFs.Further,COFs are ideally suitable for constructing ordered nanochannels with size in the range of 0.6−3 nm which is difficult to be realized by other materials.(ii)Second,along with the unremitting discovery of diverse platform chemistries such as reticular chemistry,the in-depth understanding of nucleation/growth mechanisms of COFs as well as the rapid progress of manufacturing technologies and various routes to fabricating COF membranes with favorable physical and chemical structures inside the nanochannels are being actively exploited.COFs generally show better membrane-formation ability owing to their abundant 2D structures,which make it easier to fabricate ultrathin membranes compared with zeolite and MOFs.(iii)Last,a great number of COF membranes exhibit exceptionally high separation performance and stability,establishing their position as the next-generation membranes.In this Account,we discuss three types of engineering toward COF membranes based on Schiff base reaction for high-efficiency molecules/ion separations,i.e.,reticular engineering,crystal engineering,and nanochannel engineering.First,we discuss the reticular engineering of COF membranes with a focus on the bond types,chemical structure,and architecture design.The membraneformation ability and methods of COFs are also analyzed.Second,we discuss the crystal engineering of COF membranes with a focus on the key thermodynamical and kinetic factors to drive the disorder-to-order transition where we attempt to dig deeper into the crystallization habit of COF membranes.Third,we discuss nanochannel engineering of COF membranes with a focus on the construction and modulation of the physical and chemical microenvironments of nanochannels for efficient and selective transport of molecules/ions.Last,we conclude with a perspective on the opportunities and major challenges in the R&D of COF membranes,targeting at identifying the future directions. | Guangwei He Runnan Zhang Zhongyi Jiang | 2021 | Accounts of Materials Research2021，2，8： | 4 |
| 6 | Two-Dimensional-Material Membranes:Manipulating the Transport Pathway for Molecular Separation显示文摘CONSPECTUS:The discovery of graphene triggers a new era of two-dimensional(2D)materials,which exhibit great potential in condensed matter physics,chemistry,and materials science.Meanwhile,the booming of 2D materials brings new opportunities for the next generation of high-performance(high permeability,selectivity,and stability)separation membranes.Two-dimensional materials with atomic thinness can serve as new building blocks for fabricating ultrathin membranes possessing the ultimate permeation rate.The plane structure with micrometer lateral dimensions provides an excellent platform for the orderly alignment of the nanosheets.Moreover,the apertures of two-dimensional-material membranes(2DMMs),including the in-plane nanopores and interlayer channels,can contribute to the fast and selective transport of small molecules/ions related to molecular separation.Therefore,the emerging 2D materials with various nanostructures,including graphene oxide(GO),zeolite nanosheets,metal−organic framework(MOF)nanosheets,and transition-metal carbides/carbonitrides(MXene),can be assembled into highperformance membranes.Various assembly methods such as filtration,spin coating,and hot dropping have been employed to fabricate 2DMMs,while the processes for separating small molecules/ions tend to demand higher precision,especially in water desalination and gas separation.The nanostructures of 2DMMs and the physicochemical properties of transport pathway need to be finely tuned to meet the requirement.In addition,the stability of 2DMMs,which is critical to the large-scale implementation,must be taken into consideration as well.In this Account,we discuss our recent progress in manipulating molecular transport pathways in 2DMMs by optimizing the assembly behavior of 2D nanosheets,tuning the microstructure of interlayer channels,and controlling the physicochemical properties of the membrane surface.Assembly methods,including vacuum suction assembly,polymer-induced assembly,and external force-driven assembly,have been proposed to construct ordered laminates for molecular transport.The size and chemical structure of interlayer channels were further tailored by strategies such as nanoparticle intercalation,cationic control,and chemical modification.Interestingly,the manipulation of surface properties of 2DMMs was proven to contribute to fast molecular transport through interlayer channels.Moreover,the issues concerning 2DMMs toward practical applications are discussed with an emphasis on the substrate effect,molecular bridge strategy,and preliminary progress in large-scale fabrication.Finally,we conclude this Account with an overview of the remaining challenges and the new opportunities that will be opened up for 2DMMs in molecular separation. | Long Cheng Gongping Liu Jing Zhao Wanqin Jin | 2021 | Accounts of Materials Research2021，2，2： | 4 |
| 7 | Toward Practical Solid-State Lithium−Sulfur Batteries: Challenges and Perspectives显示文摘CONSPECTUS:The energy density of the ubiquitous lithium-ion batteries is rapidly approaching its theoretical limit.To go beyond,a promising strategy is the replacement of conventional intercalation-type materials with conversion-type materials possessing substantially higher capacities.Among the conversion-type cathode materials,sulfur constitutes a cost-effective and earth-abundant element with a high theoretical capacity that has a potential to be game-changing,especially within an emerging solid-state battery configuration.Employment of nonflammable solid electrolytes that improves battery safety and boosts the energy density,as lithium metal anodes are also viable.The long-standing inherent problem of conventional lithium−sulfur batteries,arising from the reaction intermediates dissolved in liquid electrolytes,can be eliminated with inorganic solid ion conductors.In particular,the highly conducting and easily processable lithium-thiophosphates have successfully enabled the lab-scale solid-state lithium−sulfur cells to achieve close-to-theoretical capacities.For applications requiring safe,energy-dense,lightweight batteries,solid-state lithium−sulfur batteries are an ideal choice that could surpass conventional lithium-ion batteries. | Saneyuki Ohno Wolfgang G.Zeier | 2021 | Accounts of Materials Research2021，2，10： | 4 |
| 8 | Sulfidized Nanoscale Zero-Valent Iron:Tuning the Properties of ThisComplex Material for Efficient Groundwater Remediation显示文摘CONSPECTUS:Groundwater contamination by halogenated organic compounds,especially chlorinated and fluorinated ones,threatens freshwater sources globally.Nanoscale zero-valent iron(NZVI)has been extensively studied(>5000 publications)and deployed for in situ groundwater remediation,but NZVI selectivity for contaminants is poor,reactive lifetimes are short,and it cannot promote defluorination reactions.Recently,sulfidized NZVI(SNZVI)has emerged,and has revitalized academic and industrial interests in this material for remediation.Sulfidation broadens the range of reactive contaminants,and significantly increases the selectivity and reactive lifetime of NZVI by 2 orders of magnitude,while inhibiting the undesirable H2 evolution reaction between Fe0 and water.This Account provides a state-of-the-art understanding of the chemical properties controlling the reactivity and selectivity of SNZVI and will advance the field toward the rational design of efficient groundwater remediation materials.SNZVI is a complex mixture of reactive body-centered cubic(BCC)metallic iron and unspecified iron sulfides.Most published SNZVI research has aimed at exploring the breadth of its reactivity toward various environmental contaminants rather than understanding the factors that influence the reactivity of this complex mixture of materials.Recent works from our laboratory have aimed at tuning the synthesis conditions to control the amount and speciation of sulfur in the SNZVI structure,and elucidating how these structural changes result in physicochemical properties(e.g.,hydrophobicity,electron-transfer resistance,and H adsorption sites)that provide desirable reactivity and selectivity for important groundwater contaminants.This Account explains the reasons for the more desirable properties of SNZVI compared to NZVI.The degradation pathways,and reactive sites(Fe or S sites)and species(direct electron transfer or atomic H)of SNZVI for the dechlorination of trichloroethene and defluorination of florfenicol are determined from batch experiments,theoretical calculations,and analysis of degradation products.A better understanding of why SNZVI is reactive with C−F bonds under ambient conditions may also promote the use of SNZVI and its derivatives for the defluorination of emerging groundwater contaminants.Finally,this Account provides guidance for measuring and reporting the complex material properties of SNZVI.This will enable comparisons between future studies to elucidate the reasons for differences in the reactivity of SNZVI synthesized by different research groups.Overall,this Account unveils the structure−property−performance relationships of SNZVI,makes strides toward the controlled synthesis and rational design of robust SNZVI with properties tailored for specific application scenarios,and provides mechanistic insights into SNZVI materials for in situ groundwater remediation of chlorinated and fluorinated contaminants. | Jiang Xu Hao Li Gregory V.Lowry | 2021 | Accounts of Materials Research2021，2，6： | 4 |
| 9 | Engineering Hydrogels for Efficient Solar Desalination and Water Purification显示文摘CONSPECTUS:Safe and adequate water is a global challenge due to the growing population and pollution in the wake of natural disasters.Access to clean water is a cornerstone for the further development of our modern society.Solar-powered desalination and water purification have attracted much research attention due to the high solar-to-thermal conversion efficiency and ease of implementation in multiple scales,from compact,stand-alone devices for individual households to large,centralized dimensions for communities.Nevertheless,the generation of water vapor at low temperatures below the boiling point is usually a slow process under natural sunlight.The production rate of clean water relies on the efficiencies of solar energy conversion and utilization,which can be enhanced in two directions:systems optimization and materials innovation.Starting from bottom heating and volumetric heating,interfacial evaporation has been adopted recently to systematically reduce energy loss by localizing heat near the evaporation surface using photothermal materials.Meanwhile,carbonaceous materials,narrow bandgap semiconductors,and polymers with different structures were designed to achieve thermal management and water transport.In this Account,we highlight the recent progress of hydrogels as a highly tunable material platform for solar-powered desalination and water purification.We begin by introducing how gelation chemistry endows hydrogels with desirable properties and multiscale tunability from molecular to macroscopic levels.Then,we review three major strategies to promote efficient solar-to-vapor conversion in terms of reducing water evaporation enthalpy,optimizing heat distribution,and tailoring the evaporation surface.First,by selecting polymeric backbones with hydratable functional groups,the water state in hydrogels can be regulated to facilitate intermediate water,which has a lower evaporation enthalpy compared to that of the bulk water.This polymer−water interaction can be further tuned during synthesis and post-treatment.Second,light-absorbing additives within hydrogels should not only convert solar energy to heat effectively but also confine the heat near the evaporative surfaces.Third,since water molecules are encapsulated in the polymer network of hydrogels,the surface of the hydrogel becomes the evaporation front of liquid water.Hence,tailoring the surface topography and wettability of hydrogels has important effects on the evaporation rate.Next,we discuss key functions that endow hydrogel evaporators with excellent desalination and purification performances,including anti-salt-fouling property for stable and long-term desalination,as well as easy integration of functional materials to remove other contaminants,such as heavy metal ions and organic dyes,for greater distillate quality.Last,existing challenges and future opportunities in both fundamental studies and practical implementation of the hydrogel-based solar water purification systems are discussed. | Youhong Guo Guihua Yu | 2021 | Accounts of Materials Research2021，2，5： | 4 |
| 10 | Carbon-Based Metal-Free Electrocatalysts:Past,Present,and Future显示文摘CONSPECTUS:Due to the overuse of fossil fuels,various detrimental effects along with the excess CO_(2)emissions have induced global warming and sea-level rising.To tackle climate change and provide a cleaner environment for the air we breathe and water we consume,the existing energy mix needs to be changed into fossil-free,clean,renewable energy with zero emission(e.g.,fuel cells).While providing a promising and scalable strategy to the energy and environmental challenges,renewable energy processes often involve noble-metal-based catalysts(i.e.,Pt,RuO_(2)).However,the disadvantages of noblemetal-based catalysts,including their high cost and scarcity,have hampered the large-scale application of renewable energy technologies.In 2009,we discovered earth-abundant carbon materials functioning as efficient low-cost,carbon-based metal-free electrocatalysts(C-MFECs)attractive for renewable energy and environmental remediation.Since then,C-MFECs have become an emerging new research field over the world.They are demonstrated to be efficient multifunctional catalysts for various key reactions important to renewable energy and environmental technologies,including oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),oxygen evolution reaction(OER),CO_(2)reduction reaction(CO_(2)RR),and N_(2)reduction reaction(NRR),to name a few.Charge transfer/redistribution induced by heteroatom(e.g.,N)and/or defect doping was recognized as the driving force for the metal-free catalytic activities.This finding has been used as a guidance to design and develop various new and multifunctional C-MFECs for many reactions even beyond the renewable energy and environmental remediation.In this Account,we first summarize our previous work on the development and mechanistic understanding of C-MFECs for ORR,HER,and OER to promote renewable energy conversion and storage.Then,we present recent advances in C-MFECs for new important reactions for environment remediation(e.g.,CO_(2)RR,NRR),seawater splitting,and metal−CO_(2)batteries.However,different dopant locations for C-MFECs even with the same doping element and content can cause variable catalytic properties for heteroatom-doped carbon materials.Therefore,vast opportunities remain for further developing numerous innovative C-MFECs with defined structures to gain a better understanding of their structure-based properties.In this context,we finally conclude with the current challenges and future perspectives in this exciting field. | Qingfeng Zhai Ying Pan Liming Dai | 2021 | Accounts of Materials Research2021，2，12： | 3 |
| 11 | Interfacial Solar Vapor Generation:Materials and Structural Design显示文摘The global water scarcity and deteriorating environment call for the development of environmentally friendly water treatment technologies.Solar-driven evaporation,well-known as a critical step of water cycles,provides a natural inspiration for water treatment and purification with a minimized carbon footprint.The emergence of interfacial solar vapor generation enabled through carefully tailored materials design in recent years offers an effective approach to enhance solar evaporation,with unique thermodynamic and kinetic advantages.Thermodynamically,by localizing absorbed solar energy at the water surface to avoid thermal dissipation into the entire body of water,high solar vapor transfer efficiency can be achieved.Kinetically,because of reduced thermal mass,a short response time of vapor generation and fast ramping of vapor temperature can be expected.In this perspective review,we start by exhibiting the structural designs of interfacial solar vapor generators to improve the energy transfer efficiency and evaporation rate:first,tuning optical structures to improve the light absorption;second,designing a two-dimensional water path and bioinspired structures to reduce the heat loss;third,harvesting environmental energy as an extra energy input to further increase the evaporation rate.Then,we demonstrate the intrinsic thermodynamic and kinetic advantages of interfacial solar evaporation for various applications.On the thermodynamic side,low energy loss and a high evaporation rate enable effective desalination and water treatment.While on the kinetic side,quick-response and high-temperature steam generation has direct implications in fields like sterilization and power generation.In the end,we briefly conclude the main challenges in fundamental and technical aspects as well as discuss various promising pathways for future development. | Xinzhe Min Bin Zhu Bo Li Jinlei Li Jia Zhu | 2021 | Accounts of Materials Research2021，2，4： | 3 |
| 12 | Enhancements in the Mechanical Stretchability and Thermoelectric Properties of PEDOT:PSS for Flexible Electronics Applications显示文摘CONSPECTUS:Intrinsically conducting polymers can have important application in flexible electronic devices and systems owing to their high mechanical flexibility.Among them,poly(3,4-ethylenedioxythiophene):-polystyrenesulfonate(PEDOT:PSS)is particularly important,because it can be dispersed in water or polar organic solvents while most of conducting polymers are intractable and insoluble.In addition,PEDOT:PSS can have high transparency in the visible range,excellent thermal stability,and high conductivity.Thus,it can have important applications in many areas,such as in electronic devices,peculiarly optoelectronic devices like light-emitting diodes(LEDs),solar cells and photodetectors,and energy storage devices including batteries and supercapacitors.Although PEDOT:PSS can have high conductivity and excellent biocompatibility,its stretchability is limited.Stretchable conductors are crucial for stretchable electronic systems.The stretchability of PEDOT:PSS can be enhanced by blending with a soft polymer or elastomer or plasticization.The blends of PEDOT:PSS with waterborne polyurethane(WPU)can have a conductivity of∼80 S/cm and an elongation at break of>30%.We demonstrated their applications as stretchable electromagnetic shielding,stretchable thermotherapy,and compliant electrodes of soft robots.We also found that D-sorbitol that is biocompatible and a solid at room temperature can serve as a plasticizer of PEDOT:PSS.It can enhance the conductivity of PEDOT:PSS to>1000 S/cm and the elongation at break to>60%.The plasticization mechanism is related to the hydrogen bond formation between D-sorbitol and PSSH of PEDOT:PSS.PEDOT:PSS with high thermoelectric properties can be used for flexible thermoelectric generators.It should have both high conductivity and a high Seebeck coefficient.But conductivity and the Seebeck coefficient are interdependent.The thermoelectric properties of PEDOT:PSS can be enhanced by dedoping or energy filtering.PEDOT:PSS with a power factor of 332μW/(m K^2)can be attained through the successive treatments with acid and base,because the acid treatment can enhance its conductivity and the base treatment can enhance its Seebeck coefficient by dedoping PEDOT:PSS.Dedoping PEDOT:PSS by bases is more effective in enhancing the Seebeck coefficient than dedoping by reducing agents.Coating a layer of an ionic liquid on the acid-then-base treated PEDOT:PSS can enhance the Seebeck coefficient up to 70μV/K,power factor to 750μW/(m K2),and figure of merit(ZT)to 0.75.The ZT value is comparable to the best inorganic thermoelectric materials at room temperature.The enhancement in the Seebeck coefficient by ionic liquids is ascribed to the energy filtering owing to the ion accumulations at the two ends of the ionic liquid layer under a temperature gradient.This can be obtained by coating a layer of polyelectrolyte as well.Moreover,coating a layer of Rhodamine 101 that is a zwitterion with a high intrinsic dipole moment can also enhance the Seebeck coefficient of PEDOT:PSS.Because the Seebeck coefficient enhancement is consistent with the work function decrease of PEDOT:PSS,we proposed the surface energy filtering mechanism for the Rhodamine 101 effect.The intrinsic dipole moment and interfacial dipole moment of Rhodamine 101 can block the charge carriers with low energy and thus increase the Seebeck coefficient of PEDOT:PSS. | Hao He Jianyong Ouyang | 2020 | Accounts of Materials Research2020，1，2： | 3 |
| 13 | Precise Regulation of Ga-Based Liquid Metal Oxidation显示文摘CONSPECTUS:Liquid metals,defined as metals or alloys with melting points below or near room temperature,can be regarded as an amorphous solid without any crystallinity in the molten state,exhibiting fundamentally different fluidities and metallicities from solid metals and other liquids.In the past decade,gallium as a typical representative liquid metal with a melting point of∼29.8°C,virtually nonexistent vapor pressure,and negligible toxicity has been proposed as a base material for the construction of gallium(Ga)-based liquid metals(LMs).This class of extraordinary materials with unique physicochemical properties,such as superb thermal and electrical conductivity,fluidity,shape transformability,self-healing capability and biocompatibility,biodegradability,catalytic properties,plasmonic effect,and facile functionalization accessibility,has attracted considerable attention in widespread applications.Generally,under the action of ambient oxygen and water,the ultrathin oxide layers will be formed at the LM−ambient environment interface,which may provide a physical,chemical,and electrical barrier to prevent the LMs from further oxidation.The introduction of excitations,such as electrical,chemical,electrochemical,mechanical,and ultrasonic,and the alteration of reaction conditions including ingredients,temperature,and time will promote oxide formation.However,the existence of oxides is a double-edged sword,sometimes considered as a nuisance because of the deterioration of performance and stability;for example,the oxides will adhere to the system,which brings problems for fluidic applications(such as heat-transfer media,pump media,and microfluidity).Conversely,in some cases,oxides are considered essential to improve functionality,such as shape transformation,substrate adhesion,intracellular uptake,etc.For this reason,the main aim of oxidation regulation is to alter the fundamental physicochemical properties or even endow distinct and fascinating properties for the LMs,thereby expanding the scope of applications.Although technological advances have shown dramatic progress and great potential of the LMs,their oxidation regulation remains in its infancy,thus deserving further attention.In this Account,we present a relatively elaborate summary of the oxidation regulation of LMs.First,the fundamental properties of LM oxides and their performance impact on LMs are reviewed.Then,the visions expanding to precise oxidation regulation in terms of vital structural statuses of LMs.After that,representative applications focusing on our own contributions to this field in recent years are described.Finally,brief perspectives and challenges are also presented here.Overall,this Account not only sheds light on the valuable balance between pristine LMs and oxides but also proposes prospective principles for the design and synthesis of advanced LM materials with tunable or even unprecedented properties. | Dawei Wang Xiaohong Wang Wei Rao | 2021 | Accounts of Materials Research2021，2，11： | 3 |
| 14 | Experiment Study on Dynamic Effects of Ice Shedding on Overhead Transmission Line显示文摘 | Li Xin Li Jun Liang Zhao Hong Xin Cai | 2013 | Advanced Materials Research . 2013 (710)2013，，710： | 3 |
| 15 | Stimulus-Responsive Room Temperature Phosphorescence Materials:Internal Mechanism,Design Strategy,and Potential Application显示文摘CONSPECTUS:Room temperature phosphorescence(RTP)materials,which could respond to external stimuli,such as force,heat,light,electric filed,etc.,have drawn increasing attention for their broad application prospects,especially in the fields of anticounterfeiting,sensors,data storage,and so on.In comparison with the traditional fluorescence ones,RTP materials show much longer emission lifetimes,which can be even caught by the naked eye.Thus,the change in emission lifetime under an external stimulus for RTP materials can be also a potential monitoring parameter,in addition to emission color and intensity.In other words,the number of visual monitoring parameters could increase from two to three in RTP materials,which would greatly facilitate their practical applications.Until now,RTP materials have been typically limited to metal-containing inorganic materials,particularly rare-earth phosphors.Their emissions are governed by the slow liberation of trapped charge carriers from isolated traps of impurities,defects,or ions through thermal stimulation with low luminescence efficiency.However,these materials suffer from some intrinsic disadvantages,including high cost,potential toxicity,and instability in aqueous environments.In order to solve these problems,the purely organic RTP materials should be a good choice.However,these kinds of materials are really scarce now,especially for the ones with stimulus response characteristic.To develop purely organic RTP materials with a stimulus response effect,we and other scientists have tried a lot.Luckily,some progresses have been made.In this Account,we present our recent progress on the stimulus-responsive room temperature phosphorescence of organic materials,mainly focusing on the internal mechanism and potential applications.First,the fundamental knowledge is described to illustrate the importance and main principles of the stimulus-responsive RTP effect.Then,some typical stimulus-responsive RTP materials based on different internal mechanisms are discussed.Mainly,two kinds of stimulus-responsive RTP materials were introduced,namely,single-component and multicomponent ones.Correspondingly,their dynamic change of the RTP property under external stimulus occurred based on the distinct internal mechanisms.For single-component materials,the changes in molecular structure,packing,or conformation,have played a significant role in their corresponding stimulus-responsive RTP effect.As for multicomponent materials,the changed oxygen concentration in matrix and intermolecular distance between different components were found more during the stimulus-responsive RTP process.Accordingly,different potential applications were explored based on the different stimulus-responsive RTP processes.With the classification of stimulus-responsive RTP materials based on different internal mechanisms,the corresponding design strategy could be well proposed,thus guiding the further development of this research field. | Jie Yang Manman Fang Zhen Li | 2021 | Accounts of Materials Research2021，2，8： | 3 |
| 16 | Effects of Si Addition on Microstructure,Properties and Serration Behaviors of Lightweight Al-Mg-Zn-Cu Medium-entropy Alloys显示文摘A series of as-cast lightweight multicomponent alloys Al(86-x)Mg10Zn2Cu2Six(x=0,0.3,0.6,0.9,1.2 at.%)were prepared by a vacuum induction furnace with a steel die.With the addition of Si,the reticular white Al-Cu phase deposited were gradually replaced by the gray eutectic Mg-Si phase,while the compressive strength of the alloys increases first and then decreases slowly.It is particularly noteworthy that the compression plasticity also exhibits this trend.When the Si content is 0.9 at.%,the compressive strength reaches its maximum at 779.11 MPa and the compressive plasticity reaches 20.91%.The effect of the addition of Si on the serration behavior of alloy was also studied;we found that the addition of Si introduces a new MgSi phase,and with the change of Si is significantly affects the morphology of the precipitated phase,which affects the serration behavior of the alloys.The comprehensive mechanical properties of the alloy are optimal at the critical point where the serration behavior disappears.In this work,we have provided a method and a composition for the preparation of a low-cost,high-strength,lightweight medium-entropy alloys. | Yasong Li Ruixuan Li Yong Zhang | 2019 | Research and Application of Materials Science2019，1，1： | 3 |
| 17 | Synthesis of size-tunable mesoporous anatase titania spheres by a template-free method显示文摘 | Sheng Li Qianhong Shen Jianjuan Zong Hui Yang | 2010 | Materials Research Bulletin2010，，： | 3 |
| 18 | Fabrication and Growing Kinetics of Highly Dispersed Gadolinium Zirconate Nanoparticles显示文摘Highly dispersed gadolinium zirconate(GZ)nanoparticles with fluorite structure were successfully synthesized by co-precipitation method,and their phase composition and microstructure,formation mechanism,and grain growth kinetics were investigated.The results suggest that the nanoparticles were obtained through hydroxide dehydration and solid phase reaction.High dispersion was accomplished by ethanol solvent to reduce the hydrogen bond and sodium dodecyl benzene sulfonate(SDBS)surfactant to increase the electrostatic repulsion between the nanoparticles.The grain growth activation energy of GZ powders calcined at lower temperature(<1200°C)is 86.5 kJ/mol(Ql),and the grain growth activation energy of GZ powders calcined at higher temperature(>1200°C)is 148.4 kJ/mol(Qh).The current study shows that the optimal process to synthesize dispersed GZ nanoparticles includes ethanol solvent,3 wt.%SDBS surfactant,and 1100°C as calcining temperature. | Renbo Zhu Jianpeng Zou Jie Mao Xiaofeng Zhang Chunming Deng Min Liu Wenlong Chen | 2019 | Research and Application of Materials Science2019，1，1： | 3 |
| 19 | Regulation Strategy of Transition Metal Oxide-Based Electrocatalysts for Enhanced Oxygen Evolution Reaction显示文摘CONSPECTUS:The deployment of hydrogen as alternative energy carrier is a promising route to reduce the consumption of fossil fuel and achieve the“zero carbon”target.Water electrolysis,powered by renewable energy sources,is regarded as the most environmentally friendly and efficient technology for hydrogen production.Generally,the sluggish oxygen evolution reaction(OER)process at the anode predominantly limits the efficiency of water electrolysis. | Yuanyuan Zhang Qiang Fu Bo Song Ping Xu | 2022 | Accounts of Materials Research2022，3，10： | 3 |
| 20 | Metastable Two-Dimensional Materials for Electrocatalytic Energy Conversions显示文摘CONSPECTUS:An urgent need for efficient energy conversion technologies is driving development of active and durable electrocatalysts.In recent years,two-dimensional(2D)materials have emerged as practically promising electrocatalysts because of unique physical and chemical properties.In general,a significant proportion of 2D materials are polymorphous with diverse crystal structures or stoichiometry.However,pristine 2D materials found in nature are thermodynamically stable phases with inert catalytic activity.Metastable phases,in contrast,are highly active for various electrocatalytic processes because of high-energy structures and high reactivity of nonequilibrium surfaces.Generally,the growth of metastable 2D materials requires higher formation energy compared with the thermodynamically stable phases,which are difficultly obtained in standard synthetic processes such as chemical vapor deposition and vapor transport processes.The destabilization of thermodynamically stable 2D materials via external forces facilitates the conversion of highentropy crystal structure into metastable phases.To date,a number of approaches,including confined growth,topotactic transformation,electron donating,and chemical exfoliation,have been demonstrated for the preparation of high-performance metastable 2D electrocatalysts.As an atomic thin platform,metastable 2D materials represent an almost ideal prototype to achieve a comprehensive understanding of the fundamental principles and mechanisms of various electrocatalytic processes.In the design of metastable 2D electrocatalysts,a number of needs must be concomitantly considered,namely,(1)economic of synthesis methods,(2)product yield,(3)applicability of post-treatment for tuning electrocatalytic properties,(4)general synthesis protocols,and(5)the chemical and catalytic stabilities of metastable 2D materials.In this Account,we provide a critical and timely overview of metastable 2D materials for major electrocatalytic energy conversions based on recent research in our group.We review unique advances and challenges with metastable 2D materials,including specific design principles and typical strategies for synthesis of metastable 2D nanostructured materials with desirable characteristics.We compare advances in metastable 2D materials in selected electrocatalytic processes from fundamental through to functional.Significant emphasis is placed on design strategies for metastable 2D materials and resultant influence on intrinsic electrocatalytic performance,including electronic properties and adsorption energetics.We conclude with an appraisal of the likely opportunities and difficulties with metastable 2D electrocatalysts at the atomic level.This Account provides understandings and insights to the research of metastable 2D electrocatalysts.The current achievements of metastable 2D materials with the ultimate target of synthesizing high performance electrocatalysts may facilitate the development of heterogeneous catalysis for clean energy applications. | Huanyu Jin Taeseup Song Ungyu Paik Shi-Zhang Qiao | 2021 | Accounts of Materials Research2021，2，7： | 3 |
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