Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic conductivit...Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic conductivity.However,the typical synthesis of Ga-LLZO is usually accompanied by the formation of undesired LiGaO_(2) impurity phase that causes severe instability of the electrolyte in contact with molten Li metal during half/full cell assembly.In this study,we show that by simply engineering the defect chemistry of Ga-LLZO,namely,the lithium deficiency level,LiGaO_(2) impurity phase is effectively inhibited in the final synthetic product.Consequently,defect chemistry engineered Ga-LLZO exhibits excellent electrochemical stability against lithium metal,while its high room temperature ionic conductivity(~1.9×10^(-3)S·cm^(-1))is well reserved.The assembled Li/Ga-LLZO/Li symmetric cell has a superior critical current density of 0.9 mA·cm^(-2),and cycles stably for 500 hours at a current density of 0.3 mA·cm^(-2).This research facilitates the potential commercial applications of high performance Ga-LLZO solid electrolytes in ASSLBs.展开更多
Phosphides possess large reversible capacity, small voltage hysteresis, and high energy efficiency, thus promising to be new anode candidates to replace commercial graphite for Li-ion batteries(LIBs).Through a facile ...Phosphides possess large reversible capacity, small voltage hysteresis, and high energy efficiency, thus promising to be new anode candidates to replace commercial graphite for Li-ion batteries(LIBs).Through a facile mechanochemistry method, we prepare a novel ternary phosphide of Ga0.5Al0.5P whose crystalline structure is determined to be a cation-disordered cubic zinc sulfide structure according to XRD refinement. As an anode for LIBs, the Ga0.5Al0.5P delivers a reversible capacity of 1,352 mA h g^(-1)at100 mA g^(-1)with an initial Coulombic efficiency(ICE) up to 90.0% based on a reversible Li-storage mechanism integrating intercalation and subsequent conversion processes as confirmed by various characterizations techniques including in-situ XRD, ex-situ Raman, and XPS and electrochemical characterizations.Graphite-modified Ga0.5Al0.5P exhibits a long-lasting cycling stability of retaining 1,182 mA h g^(-1)after300 cycles at 100 m A g^(-1), and 625 mA h g^(-1)after 800 cycles at 2,000 mA g^(-1), and a high-rate performance of remaining 342 m A h g^(-1)at 20,000 mA g^(-1). The outstanding electrochemical performances can be attributed to enhanced reaction kinetics enabled by the capacitive behaviors and the faster Liion diffusion enabled by the cation-mixing. Importantly, by tuning the cationic ratio, we develop a novel series of cation-mixed compounds of Ga_(1/3)Al_(2/3)P, Ga_(1/4)Al_(3/4)P, Ga_(1/5)Al_(4/5)P, Ga_(2/3)Al_(1/3)P, Ga_(3/4)Al_(1/4)P, and Ga_(4/5)Al_(1/5)P, which demonstrate large capacity, high ICE, and suitable anode potentials. Broadly, these compounds with disordered lattices probably present novel physicochemical properties, and high electrochemical performances, thus providing a new perspective for new materials design.展开更多
Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and...Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.展开更多
Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-fr...Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g^(-1)at a current density of 200 mA g^(-1).It also shows good rate performance with reversible capacity of 517 mAh g^(-1)under a high-current density of 5000 mA g^(-1).In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.展开更多
Ingenious design and fabrication of advanced carbon-based sulfur cathodes are extremely important to the development of high-energy lithium-sulfur batteries,which hold promise as the next-generation power source.Herei...Ingenious design and fabrication of advanced carbon-based sulfur cathodes are extremely important to the development of high-energy lithium-sulfur batteries,which hold promise as the next-generation power source.Herein,for the first time,we report a novel versatile hyphae-mediated biological assembly technology to achieve scale production of hyphae carbon fibers(HCFs)derivatives,in which different components including carbon,metal compounds,and semiconductors can be homogeneously assembled with HCFs to form composite networks.The mechanism of biological adsorption assembly is also proposed.As a representative,reduced graphene oxides(rGOs)decorated with hollow carbon spheres(HCSs)successfully co-assemble with HCFs to form HCSs@rGOs/HCFs hosts for sulfur cathodes.In this unique architecture,not only large accommodation space for sulfur but also restrained volume expansion and fast charge transport paths are realized.Meanwhile,multiscale physical barriers plus chemisorption sites are simultaneously established to anchor soluble lithium polysulfides.Accordingly,the designed HCSs@rGOs/HCFs-S cathodes deliver a high capacity(1189 mA h g^(-1)at 0.1 C)and good high-rate capability(686 mA h g^(-1)at 5 C).Our work provides a new approach for the preparation of high-performance carbon-based electrodes for energy storage devices.展开更多
Due to their excellent photoelectron chemical properties and suitable energy level alignment with perovskite,perylene diimide(PDI)derivatives are competitive non-fullerene electron transport material(ETM)candidates fo...Due to their excellent photoelectron chemical properties and suitable energy level alignment with perovskite,perylene diimide(PDI)derivatives are competitive non-fullerene electron transport material(ETM)candidates for perovskite solar cells(PSCs).However,the conjugated rigid plane structure of PDI units result in PDI-based ETMs tending to form large aggregates,limiting their application and photovoltaic performance.In this study,to restrict aggregation and further enhance the photovoltaic performance of PDI-type ETMs,two PDI-based ETMs,termed PDO-PDI2(dimer)and PDO-PDI3(trimer),were constructed by introducing a phenothiazine 5,5-dioxide(PDO)core building block.The research manifests that the optoelectronic properties and film formation property of PDO-PDI2 and PDO-PDI3 were deeply affected by the molecular spatial configuration.Applied in PSCs,PDO-PDI3 with threedimensional spiral molecular structure,exhibits superior electron extraction and transport properties,further achieving the best PCE of 18.72%and maintaining 93%of its initial efficiency after a 720-h aging test under ambient conditions.展开更多
To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane(CL-20)co-crystals,shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene(TNT),1,3-dinitro...To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane(CL-20)co-crystals,shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene(TNT),1,3-dinitrobenzene(DNB),solvents ligands dimethyl carbonate(DMC) and gamma-butyrolactone(GBL)with void were simulated,using molecular dynamics method and reactive force field.It is found that the CL-20 co-crystals with void defects will form hot spots when impacted,significantly affecting the decomposition of molecules around the void.The degree of molecular fragmentation is relatively low under the reflection velocity of 2 km/s,and the main reactions are the formation of dimer and the shedding of nitro groups.The existence of voids reduces the safety of CL-20 co-crystals,which induced the sensitivity of energetic co-crystals CL-20/TNT and CL-20/DNB to increase more significantly.Detonation has occurred under the reflection velocity of 4 km/s,energetic co-crystals are easier to polymerize than solvent co-crystals,and are not obviously affected by voids.The results show that the energy of the wave decreases after sweeping over the void,which reduces the chemical reaction frequency downstream of the void and affects the detonation performance,especially the solvent co-crystals.展开更多
From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exh...From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.展开更多
While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LED...While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LEDs).Rather,quasi-two-dimensional(Q-2D)perovskites offer high photoluminescence quantum yield along with the advantages of bulk perovskites,making them ideal for high-performance LEDs.In Q-2D perovskites,the structure(which includes factors like crystal orientation,phase distribution,and layer thickness)directly influences how excitons and charge carriers behave within the material.Growth control techniques,such as varying the synthesis conditions or employing methods,allow for fine-tuning the structural characteristics of these materials,which in turn affect exciton dynamics and charge transport.This review starts with a description of the basic properties of Q-2D perovskites,examines crystal growth in solution,explains how structure affects energy transfer behavior,and concludes with future directions for Q-2D perovskite LEDs.By understanding and optimizing the structure-dependent behavior,researchers can better control exciton dynamics and charge transport,which are crucial for enhancing the performance of optoelectronic devices like solar cells and LEDs.展开更多
Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRP...Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRPs)through laser-assisted metal and plastic direct joining(LAMP).This study uses the LAMP technique to produce AZ31-CFRP joints.The joining process involves as-received AZ31,HFpretreated AZ31,and thermally oxidized HF-pretreated AZ31 alloy sheets.Furthermore,the bonding strength of joints prepared with thermally oxidized AZ31 alloy sheets is examined to ascertain the combined effect of HF treatment and thermal oxidation on bonding strength.The microstructures,surface chemical interactions,and mechanical performances of joints are investigated under tensile shear loading.Various factors,such as bubble formation,CFRP resin decomposition,and mechanical interlocking considerably affect joint strength.Additionally,surface chemical interactions between the active species on metal parts and the polar amide along with carbonyl groups of polymer play a significant role in improving joint strength.Joints prepared with surface-pretreated AZ31 alloy sheets show significant improvements in bonding strength.展开更多
Sodium-ion batteries(SIBs)with advantages of abundant resource and low cost have emerged as promising candidates for the next-generation energy storage systems.However,safety issues existing in electrolytes,anodes,and...Sodium-ion batteries(SIBs)with advantages of abundant resource and low cost have emerged as promising candidates for the next-generation energy storage systems.However,safety issues existing in electrolytes,anodes,and cathodes bring about frequent accidents regarding battery fires and explosions and impede the development of high-performance SIBs.Therefore,safety analysis and high-safety battery design have become prerequisites for the development of advanced energy storage systems.The reported reviews that only focus on a specific issue are difficult to provide overall guidance for building high-safety SIBs.To overcome the limitation,this review summarizes the recent research progress from the perspective of key components of SIBs for the first time and evaluates the characteristics of various improvement strategies.By orderly analyzing the root causes of safety problems associated with different components in SIBs(including electrolytes,anodes,and cathodes),corresponding improvement strategies for each component were discussed systematically.In addition,some noteworthy points and perspectives including the chain reaction between security issues and the selection of improvement strategies tailored to different needs have also been proposed.In brief,this review is designed to deepen our understanding of the SIBs safety issues and provide guidance and assistance for designing high-safety SIBs.展开更多
Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step s...Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.展开更多
Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate t...Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great challenge.Here,density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO_(4)atomic-layer(110)/(110)facet S-scheme heterojunction.Subsequently,a CdS quantum dots/InVO_(4)atomic-layer was synthesized by in-situ loading of CdS quantum dots with(110)facets onto the(110)facets of InVO_(4)atomic-layer.As a result of the deliberately constructed built-in electric field between the adjoining facets,we obtain a remarkably enhanced photocatalytic degradation rate for ethylene.This rate is 13.8 times that of pure CdS and 13.2 times that of pure InVO_(4).In-situ irradiated X-ray photoelectron spectroscopy,photoluminescence and time-resolved photoluminescence measurements were carried out.These experiments validate that the built-in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers,and results in the formation of S-scheme charge transfer pathways.The reaction mechanism of the photocatalytic C_(2)H_(4)oxidation is investigated by in-situ electron paramagnetic resonance.This work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation.展开更多
Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au...Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration treatment.The well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 frameworks.This novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution reaction.The electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by Au.Meanwhile,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest value.Consequently,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery performance.The work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.展开更多
Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding...Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field.In this study,we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots(CQDs)to form CQDs/BiOCl composites by using a simple solvothermal method.The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation.Compared with bare BiOCl,the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced,and the 5 wt%CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5%after 30 min of irradiation.Moreover,photocatalytic N_(2)reduction performance was significantly improved after introducing CQDs.The 5 wt%CQDs/BiOCl composite displayed the highest photocatalytic N_(2)reduction performance to yield NH_3(346.25μmol/(g h)),which is significantly higher than those of 3 wt%CQDs/BiOCl(256.04μmol/(g h)),7 wt%CQDs/BiOCl(254.07μmol/(g h)),and bare BiOCl(240.19μmol/(g h)).Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity,remarkable electron transfer ability,and higher photocatalytic activity sites.展开更多
This paper attempts to understand the Pt-like catalytic activity of transition metal carbide Ta4C_(3) for IRR(I_(3)^(-)reduction reaction)based on the correlation of adsorption energy to d-band center(εd).Ta4C_(3) wa...This paper attempts to understand the Pt-like catalytic activity of transition metal carbide Ta4C_(3) for IRR(I_(3)^(-)reduction reaction)based on the correlation of adsorption energy to d-band center(εd).Ta4C_(3) was prepared by carbothermal reduction method with a template.Its photoelectrochemical properties were investigated as a CE(counter electrode)in DSSC(dye-sensitized solar cell).Its surface electronic structures,including DOS(density of state)andεd,and adsorption energy were computed by first-principle DFT(density functional theory).In TMC(transition metal carbide)Ta4C_(3),the interaction between Ta and C atoms makes the d-band of Ta broaden and results in the downward shift of itsεd.A moderate absorption energy corresponding to theεd is achieved,which is the nature of the Pt-like catalytic activity of Ta4C_(3).Appropriate change of adsorption energy by adjustingεd is a promising strategy to improve catalytic activity.This work is of great significance to the fundamental and application researches.展开更多
The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the rel...The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.展开更多
Metal-organic frameworks(MOFs)are of quite a significance in the field of inorganic-organic hybrid crystals.Especially,MOFs have attracted increasing attention in recent years due to their large specific surface area,...Metal-organic frameworks(MOFs)are of quite a significance in the field of inorganic-organic hybrid crystals.Especially,MOFs have attracted increasing attention in recent years due to their large specific surface area,desirable electrical conductivity,controllable porosity,tunable geometric structure,and excellent thermal/chemical stability.Some recent studies have shown that carbon materials prepared by MOFs as precursors can retain the privileged structure of MOFs,such as large specific surface area and porous structure and,in contrast,realize in situ doping with heteroatoms(eg,N,S,P,and B).Moreover,by selecting appropriate MOF precursors,the composition and morphology of the carbon products can be easily adjusted.These remarkable structural advantages enable the great potential of MOF-derived carbon as high-performance energy materials,which to date have been applied in the fields of energy storage and conversion systems.In this review,we summarize the latest advances in MOF-derived carbon materials for energy storage applications.We first introduce the compositions,structures,and synthesis methods of MOF-derived carbon materials,and then discuss their applications and potentials in energy storage systems,including rechargeable lithium/sodium-ion batteries,lithium-sulfur batteries,supercapacitors,and so forth,in detail.Finally,we put forward our own perspectives on the future development of MOF-derived carbon materials.展开更多
Bi_(2)Te_(3) based alloys have been the most widely used thermoelectric material at low temperature for many decades.Here we report Se doped n-type Mg_(3)Bi_(2) based materials with a thermoelectric figure-of-merit ZT...Bi_(2)Te_(3) based alloys have been the most widely used thermoelectric material at low temperature for many decades.Here we report Se doped n-type Mg_(3)Bi_(2) based materials with a thermoelectric figure-of-merit ZT of 0.82 at 300 K and a peak ZT of 1.24 at 498 K,which is comparable to the n-type Bi_(2)Te_(3) and Te doped Mg_(3)Bi_(1.4)Sb_(0.6).The improved thermoelectric performance is benefited from the high carrier concentration and mobility as well as the thermal conductivity reduction.The reduced resistivity increased the power factor at all measured temperatures,leading to a higher engineering ZT(ZTeng)and engineering power factor(PFeng)for n-type Mg_(3)Bi_(2).The n-type Mg_(3)Bi_(1.4)Sb_(0.6) materials are promising for thermoelectric power generation and cooling applications near room temperature.展开更多
Transition metal nitrides(TMN)have recently grabbed immensely appealing as ideal active materials in energy storage and catalysis fields on account of their remarkable electrical conductivity,excellent chemical stabil...Transition metal nitrides(TMN)have recently grabbed immensely appealing as ideal active materials in energy storage and catalysis fields on account of their remarkable electrical conductivity,excellent chemical stability,wide band gap and tunable morphology.Both pure TMN and TMN-based materials have been extensively studied concerned with their preparation approaches,nanostructures,and favored performance in various applications.However,the processes towards synthesis of TMN are numerous and complex.Choosing appropriate method to obtain target TMN with desired structure is crucial,which further affects its practical application performance.Herein,this review offers a timely and comprehensive summary of the synthetic ways to TMN and their application in energy related domains.The synthesis section is categorized into in-situ and ex-situ based on where the N element in TMN origins from.Then,overviews on the energy related applications including energy storage,electrocatalysis and photocatalysis are discussed.In the end,the problems to be solved and the development trend of the synthesis and application of transition metal nitrides are prospected.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No.52171221)the National Key Research and Development Program of China (Grant No.2019YFA0704900)。
文摘Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic conductivity.However,the typical synthesis of Ga-LLZO is usually accompanied by the formation of undesired LiGaO_(2) impurity phase that causes severe instability of the electrolyte in contact with molten Li metal during half/full cell assembly.In this study,we show that by simply engineering the defect chemistry of Ga-LLZO,namely,the lithium deficiency level,LiGaO_(2) impurity phase is effectively inhibited in the final synthetic product.Consequently,defect chemistry engineered Ga-LLZO exhibits excellent electrochemical stability against lithium metal,while its high room temperature ionic conductivity(~1.9×10^(-3)S·cm^(-1))is well reserved.The assembled Li/Ga-LLZO/Li symmetric cell has a superior critical current density of 0.9 mA·cm^(-2),and cycles stably for 500 hours at a current density of 0.3 mA·cm^(-2).This research facilitates the potential commercial applications of high performance Ga-LLZO solid electrolytes in ASSLBs.
基金supported by the National Natural Science Foundation of China (22178068)the Brain Pool program (2021H1D3A2A02045576) funded by National Research Foundation of Korea (NRF)。
文摘Phosphides possess large reversible capacity, small voltage hysteresis, and high energy efficiency, thus promising to be new anode candidates to replace commercial graphite for Li-ion batteries(LIBs).Through a facile mechanochemistry method, we prepare a novel ternary phosphide of Ga0.5Al0.5P whose crystalline structure is determined to be a cation-disordered cubic zinc sulfide structure according to XRD refinement. As an anode for LIBs, the Ga0.5Al0.5P delivers a reversible capacity of 1,352 mA h g^(-1)at100 mA g^(-1)with an initial Coulombic efficiency(ICE) up to 90.0% based on a reversible Li-storage mechanism integrating intercalation and subsequent conversion processes as confirmed by various characterizations techniques including in-situ XRD, ex-situ Raman, and XPS and electrochemical characterizations.Graphite-modified Ga0.5Al0.5P exhibits a long-lasting cycling stability of retaining 1,182 mA h g^(-1)after300 cycles at 100 m A g^(-1), and 625 mA h g^(-1)after 800 cycles at 2,000 mA g^(-1), and a high-rate performance of remaining 342 m A h g^(-1)at 20,000 mA g^(-1). The outstanding electrochemical performances can be attributed to enhanced reaction kinetics enabled by the capacitive behaviors and the faster Liion diffusion enabled by the cation-mixing. Importantly, by tuning the cationic ratio, we develop a novel series of cation-mixed compounds of Ga_(1/3)Al_(2/3)P, Ga_(1/4)Al_(3/4)P, Ga_(1/5)Al_(4/5)P, Ga_(2/3)Al_(1/3)P, Ga_(3/4)Al_(1/4)P, and Ga_(4/5)Al_(1/5)P, which demonstrate large capacity, high ICE, and suitable anode potentials. Broadly, these compounds with disordered lattices probably present novel physicochemical properties, and high electrochemical performances, thus providing a new perspective for new materials design.
基金supported by the National Natural Science Foundation of China(51872115,12234018 and 52101256)Beijing Synchrotron Radiation Facility(BSRF,4B9A)。
文摘Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.
基金support from National Natural Science Foundation of China(Nos:11874144,12174092 and U21A20500)Hubei Provincial Department of Science and Technology(No.2019CFA079)+1 种基金Wuhan Science and Technology Bureau(2020010601012163)Overseas Expertise Introduction Center for Discipline Innovation(D18025).
文摘Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g^(-1)at a current density of 200 mA g^(-1).It also shows good rate performance with reversible capacity of 517 mAh g^(-1)under a high-current density of 5000 mA g^(-1).In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.
基金Natural Science Foundation for Distinguished Young Scholars of Zhejiang Province,Grant/Award Number:LR20E020001Foundation of State Key Laboratory of Coal Conversion,Grant/Award Number:J20-21-909+4 种基金Science and Technology Department of Zhejiang Province,Grant/Award Number:2023C01231National Natural Science Foundation of China,Grant/Award Numbers:52372235,52073252,52002052,22379020,U20A20253,21972127,22279116Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment,Grant/Award Number:SKLPEE-KF202206Key Research and Development Project of Science and Technology Department of Sichuan Province,Grant/Award Number:2022YFSY0004Ministry of Education,Grant/Award Number:KFM 202202。
文摘Ingenious design and fabrication of advanced carbon-based sulfur cathodes are extremely important to the development of high-energy lithium-sulfur batteries,which hold promise as the next-generation power source.Herein,for the first time,we report a novel versatile hyphae-mediated biological assembly technology to achieve scale production of hyphae carbon fibers(HCFs)derivatives,in which different components including carbon,metal compounds,and semiconductors can be homogeneously assembled with HCFs to form composite networks.The mechanism of biological adsorption assembly is also proposed.As a representative,reduced graphene oxides(rGOs)decorated with hollow carbon spheres(HCSs)successfully co-assemble with HCFs to form HCSs@rGOs/HCFs hosts for sulfur cathodes.In this unique architecture,not only large accommodation space for sulfur but also restrained volume expansion and fast charge transport paths are realized.Meanwhile,multiscale physical barriers plus chemisorption sites are simultaneously established to anchor soluble lithium polysulfides.Accordingly,the designed HCSs@rGOs/HCFs-S cathodes deliver a high capacity(1189 mA h g^(-1)at 0.1 C)and good high-rate capability(686 mA h g^(-1)at 5 C).Our work provides a new approach for the preparation of high-performance carbon-based electrodes for energy storage devices.
基金financially supported by the National Natural Science Foundation of China(Grants 21805114,21905119)Key Research and Development program of Jiangsu Province(BE2019009-2)+4 种基金Natural Science Foundation of Jiangsu province(BK20180869,BK20180867)China Postdoctoral Science Foundation(2019M651741),Top talents in Jiangsu province(XNY066)the Jiangsu University Foundation(17JDG032,17JDG031)Hightech Research Key laboratory of Zhenjiang(SS2018002)the State Key Laboratory of Fine Chemicals(KF1902)。
文摘Due to their excellent photoelectron chemical properties and suitable energy level alignment with perovskite,perylene diimide(PDI)derivatives are competitive non-fullerene electron transport material(ETM)candidates for perovskite solar cells(PSCs).However,the conjugated rigid plane structure of PDI units result in PDI-based ETMs tending to form large aggregates,limiting their application and photovoltaic performance.In this study,to restrict aggregation and further enhance the photovoltaic performance of PDI-type ETMs,two PDI-based ETMs,termed PDO-PDI2(dimer)and PDO-PDI3(trimer),were constructed by introducing a phenothiazine 5,5-dioxide(PDO)core building block.The research manifests that the optoelectronic properties and film formation property of PDO-PDI2 and PDO-PDI3 were deeply affected by the molecular spatial configuration.Applied in PSCs,PDO-PDI3 with threedimensional spiral molecular structure,exhibits superior electron extraction and transport properties,further achieving the best PCE of 18.72%and maintaining 93%of its initial efficiency after a 720-h aging test under ambient conditions.
基金supported by the National Natural Science Foundation of China (22275018)the Project of State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology)(Grant No.QNKT20-04)。
文摘To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane(CL-20)co-crystals,shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene(TNT),1,3-dinitrobenzene(DNB),solvents ligands dimethyl carbonate(DMC) and gamma-butyrolactone(GBL)with void were simulated,using molecular dynamics method and reactive force field.It is found that the CL-20 co-crystals with void defects will form hot spots when impacted,significantly affecting the decomposition of molecules around the void.The degree of molecular fragmentation is relatively low under the reflection velocity of 2 km/s,and the main reactions are the formation of dimer and the shedding of nitro groups.The existence of voids reduces the safety of CL-20 co-crystals,which induced the sensitivity of energetic co-crystals CL-20/TNT and CL-20/DNB to increase more significantly.Detonation has occurred under the reflection velocity of 4 km/s,energetic co-crystals are easier to polymerize than solvent co-crystals,and are not obviously affected by voids.The results show that the energy of the wave decreases after sweeping over the void,which reduces the chemical reaction frequency downstream of the void and affects the detonation performance,especially the solvent co-crystals.
基金National Natural Science Foundation of China(Grant Nos.22075023,22205022,and 22235003)to provide fund for conducting experiments。
文摘From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.
文摘While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LEDs).Rather,quasi-two-dimensional(Q-2D)perovskites offer high photoluminescence quantum yield along with the advantages of bulk perovskites,making them ideal for high-performance LEDs.In Q-2D perovskites,the structure(which includes factors like crystal orientation,phase distribution,and layer thickness)directly influences how excitons and charge carriers behave within the material.Growth control techniques,such as varying the synthesis conditions or employing methods,allow for fine-tuning the structural characteristics of these materials,which in turn affect exciton dynamics and charge transport.This review starts with a description of the basic properties of Q-2D perovskites,examines crystal growth in solution,explains how structure affects energy transfer behavior,and concludes with future directions for Q-2D perovskite LEDs.By understanding and optimizing the structure-dependent behavior,researchers can better control exciton dynamics and charge transport,which are crucial for enhancing the performance of optoelectronic devices like solar cells and LEDs.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Science and ICT(RS-2023-00234757).
文摘Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRPs)through laser-assisted metal and plastic direct joining(LAMP).This study uses the LAMP technique to produce AZ31-CFRP joints.The joining process involves as-received AZ31,HFpretreated AZ31,and thermally oxidized HF-pretreated AZ31 alloy sheets.Furthermore,the bonding strength of joints prepared with thermally oxidized AZ31 alloy sheets is examined to ascertain the combined effect of HF treatment and thermal oxidation on bonding strength.The microstructures,surface chemical interactions,and mechanical performances of joints are investigated under tensile shear loading.Various factors,such as bubble formation,CFRP resin decomposition,and mechanical interlocking considerably affect joint strength.Additionally,surface chemical interactions between the active species on metal parts and the polar amide along with carbonyl groups of polymer play a significant role in improving joint strength.Joints prepared with surface-pretreated AZ31 alloy sheets show significant improvements in bonding strength.
基金supported by the Natural Science Foundation of China(52272188,U22A20227)the Natural Science Foundation of Beijing(2232025)+2 种基金the Natural Science Foundation of Chongqing(2022NSCQ-MSX2179)the Department of Science and Technology of Henan Province(Z20221343029)the Experimental Center of Advanced Materials in Beijing Institute of Technology。
文摘Sodium-ion batteries(SIBs)with advantages of abundant resource and low cost have emerged as promising candidates for the next-generation energy storage systems.However,safety issues existing in electrolytes,anodes,and cathodes bring about frequent accidents regarding battery fires and explosions and impede the development of high-performance SIBs.Therefore,safety analysis and high-safety battery design have become prerequisites for the development of advanced energy storage systems.The reported reviews that only focus on a specific issue are difficult to provide overall guidance for building high-safety SIBs.To overcome the limitation,this review summarizes the recent research progress from the perspective of key components of SIBs for the first time and evaluates the characteristics of various improvement strategies.By orderly analyzing the root causes of safety problems associated with different components in SIBs(including electrolytes,anodes,and cathodes),corresponding improvement strategies for each component were discussed systematically.In addition,some noteworthy points and perspectives including the chain reaction between security issues and the selection of improvement strategies tailored to different needs have also been proposed.In brief,this review is designed to deepen our understanding of the SIBs safety issues and provide guidance and assistance for designing high-safety SIBs.
基金supported by the National Natural Science Foundation of China(Nos.52201203 and 52171107)the Hebei Provincial Natural Science Foundation,China(No.E2021501026)+1 种基金the National Natural Science Foundation of China-Joint Fund of Iron and Steel Research(No.U1960204)the“333”Talent Project of Hebei Province,China(No.B20221001).
文摘Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace,automotive,and energy indus-tries owing to its extraordinary thermomechanical properties.The effects of different two-step solid solution treatments on microstructure andδphase precipitation of Inconel 718 alloy were studied,and the transformation mechanism fromγ″metastable phase toδphase was clarified.The precipitates were statistically analyzed by X-ray diffractometry.The results show that theδphase content firstly increased,and then decreased with the temperature of the second-step solid solution.The changes in microstructure andδphase were studied by scanning electron microscopy and transmission electron microscopy.An intragranularδphase formed in Inconel 718 alloy at the second-[100]_(δ)[011]γ step solid solution temperature of 925℃,and its orientation relationship withγmatrix was determined as//and(010)_(δ)//(111)γ.Furthermore,the Vickers hardness of different heat treatment samples was measured,and the sample treated by second-step solid solution at 1010℃ reached the maximum hardness of HV 446.84.
基金financially supported by the National Natural Science Foundation of China(Grant No.21902046,21801071,12174092,U21A20500)Overseas Expertise Introduction Center for Discipline Innovation(D18025)+3 种基金the Natural Science Foundation of Hubei Provincial(Grant No.2018CFB171)Wuhan Science and Technology Bureau(2020010601012163)Science and Technology Research Project of Hubei Provincial Department of Education(No.D20221001)the open foundation of the State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences
文摘Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great challenge.Here,density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO_(4)atomic-layer(110)/(110)facet S-scheme heterojunction.Subsequently,a CdS quantum dots/InVO_(4)atomic-layer was synthesized by in-situ loading of CdS quantum dots with(110)facets onto the(110)facets of InVO_(4)atomic-layer.As a result of the deliberately constructed built-in electric field between the adjoining facets,we obtain a remarkably enhanced photocatalytic degradation rate for ethylene.This rate is 13.8 times that of pure CdS and 13.2 times that of pure InVO_(4).In-situ irradiated X-ray photoelectron spectroscopy,photoluminescence and time-resolved photoluminescence measurements were carried out.These experiments validate that the built-in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers,and results in the formation of S-scheme charge transfer pathways.The reaction mechanism of the photocatalytic C_(2)H_(4)oxidation is investigated by in-situ electron paramagnetic resonance.This work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation.
基金National Natural Science Foundation of China,Grant/Award Numbers:52102260,52171211,51972220,61903235,U22A20145Shandong Provincial Natural Science Foundation,Grant/Award Numbers:ZR2020QB069,ZR2022ME051+4 种基金National Key Research and Development Program of China,Grant/Award Number:2022YFB4002004Scientific and Technological Innovation Ability Improvement Project of Minor Enterprises in Shandong Province,Grant/Award Number:2022TSGC1021Announce the List and Take Charge Project in Jinan,Grant/Award Number:202214012Major innovation project for integrating science,education and industry of Qilu University of Technology (Shandong Academy of Sciences),Grant/Award Numbers:2022JBZ01-07,2022PY044China Postdoctoral Science Foundation,Grant/Award Number:2022M711545。
文摘Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration treatment.The well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 frameworks.This novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution reaction.The electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by Au.Meanwhile,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest value.Consequently,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery performance.The work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.
基金financially suppor ted by Key Research and Development Project of Anhui Province(No.2023h11020002)Natural Science Research Project for Universities in Anhui Province(No.KJ2021ZD0006)+3 种基金Natural Science Foundation of Anhui Province(No.2208085MB21)Fundamental Research Funds for the Central Universities of China(No.PA2022GDSK0056)Anhui Laboratory of Molecule-Based Materials(No.fzj22009)National Natural Science Foundation of China(Nos.21725102,22205108)。
文摘Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field.In this study,we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots(CQDs)to form CQDs/BiOCl composites by using a simple solvothermal method.The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation.Compared with bare BiOCl,the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced,and the 5 wt%CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5%after 30 min of irradiation.Moreover,photocatalytic N_(2)reduction performance was significantly improved after introducing CQDs.The 5 wt%CQDs/BiOCl composite displayed the highest photocatalytic N_(2)reduction performance to yield NH_3(346.25μmol/(g h)),which is significantly higher than those of 3 wt%CQDs/BiOCl(256.04μmol/(g h)),7 wt%CQDs/BiOCl(254.07μmol/(g h)),and bare BiOCl(240.19μmol/(g h)).Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity,remarkable electron transfer ability,and higher photocatalytic activity sites.
基金Financial support for this work was provided by Key Research and Development Projects of Shanxi Province(201703D121023).
文摘This paper attempts to understand the Pt-like catalytic activity of transition metal carbide Ta4C_(3) for IRR(I_(3)^(-)reduction reaction)based on the correlation of adsorption energy to d-band center(εd).Ta4C_(3) was prepared by carbothermal reduction method with a template.Its photoelectrochemical properties were investigated as a CE(counter electrode)in DSSC(dye-sensitized solar cell).Its surface electronic structures,including DOS(density of state)andεd,and adsorption energy were computed by first-principle DFT(density functional theory).In TMC(transition metal carbide)Ta4C_(3),the interaction between Ta and C atoms makes the d-band of Ta broaden and results in the downward shift of itsεd.A moderate absorption energy corresponding to theεd is achieved,which is the nature of the Pt-like catalytic activity of Ta4C_(3).Appropriate change of adsorption energy by adjustingεd is a promising strategy to improve catalytic activity.This work is of great significance to the fundamental and application researches.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2019YFE0122900)the National Natural Science Foundation of China(No 51971162,U1933112,51671146)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M671208)Open access funding provided by Shanghai Jiao Tong University
文摘The rational construction of microstructure and composition with enhanced Maxwell-Wagner-Sillars effect(MWSE)is still a challenging direction for reinforcing electromagnetic wave(EMW)absorption performance,and the related EMW attenuation mechanism has rarely been elucidated.Herein,MWSE boostedβ-chitin/carbon nano-onions/Ni–P composites is prepared according to the heterointerface engineering strategy via facile layer-by-layer electrostatic assembly and electroless plating techniques.The heterogeneous interface is reinforced from the aspect of porous skeleton,nanomaterials and multilayer construction.The composites exhibit competitive EMW response mechanism between the conductive loss and the polarization/magnetic loss,as describing like the story of“The Hare and the Tortoise”.As a result,the composites not only achieve a minimum reflection loss(RL_(min))of−50.83 dB and an effective bandwidth of 6.8 GHz,but also present remarkable EMW interference shielding effectiveness of 66.66 dB.In addition,diverse functions such as good thermal insulation,infrared shielding and photothermal performance were also achieved in the hybrid composites as a result of intrinsic morphology and chemicophysics properties.Therefore,we believe that the boosted MWSE open up a novel orientation toward developing multifunctional composites with high-efficient EMW response and thermal management.
基金This study acknowledges the supports by the Shenzhen Science and Technology Innovation Commission under Grant JCYJ20180507181806316the City University of Hong Kong under project Fundamental Investigation of Phase Transformative Materials for Energy Application(Project No.9610399)the Shenzhen Research Institute,City University of Hong Kong.
文摘Metal-organic frameworks(MOFs)are of quite a significance in the field of inorganic-organic hybrid crystals.Especially,MOFs have attracted increasing attention in recent years due to their large specific surface area,desirable electrical conductivity,controllable porosity,tunable geometric structure,and excellent thermal/chemical stability.Some recent studies have shown that carbon materials prepared by MOFs as precursors can retain the privileged structure of MOFs,such as large specific surface area and porous structure and,in contrast,realize in situ doping with heteroatoms(eg,N,S,P,and B).Moreover,by selecting appropriate MOF precursors,the composition and morphology of the carbon products can be easily adjusted.These remarkable structural advantages enable the great potential of MOF-derived carbon as high-performance energy materials,which to date have been applied in the fields of energy storage and conversion systems.In this review,we summarize the latest advances in MOF-derived carbon materials for energy storage applications.We first introduce the compositions,structures,and synthesis methods of MOF-derived carbon materials,and then discuss their applications and potentials in energy storage systems,including rechargeable lithium/sodium-ion batteries,lithium-sulfur batteries,supercapacitors,and so forth,in detail.Finally,we put forward our own perspectives on the future development of MOF-derived carbon materials.
基金supported by Young Scientist Fund of National Natural Science Foundation of China(No.51601152)Chunhui Program from Education Ministry of China,Open Research Subject of Key Laboratory of Fluid and Power Machinery of Ministry of Education(No.SZJJ2017-082)the Sichuan Science and Technology Program(No.2019JDTD0024).
文摘Bi_(2)Te_(3) based alloys have been the most widely used thermoelectric material at low temperature for many decades.Here we report Se doped n-type Mg_(3)Bi_(2) based materials with a thermoelectric figure-of-merit ZT of 0.82 at 300 K and a peak ZT of 1.24 at 498 K,which is comparable to the n-type Bi_(2)Te_(3) and Te doped Mg_(3)Bi_(1.4)Sb_(0.6).The improved thermoelectric performance is benefited from the high carrier concentration and mobility as well as the thermal conductivity reduction.The reduced resistivity increased the power factor at all measured temperatures,leading to a higher engineering ZT(ZTeng)and engineering power factor(PFeng)for n-type Mg_(3)Bi_(2).The n-type Mg_(3)Bi_(1.4)Sb_(0.6) materials are promising for thermoelectric power generation and cooling applications near room temperature.
基金support offered by National Natural Science Foundation of China(NSFC,Grant No.21403091)。
文摘Transition metal nitrides(TMN)have recently grabbed immensely appealing as ideal active materials in energy storage and catalysis fields on account of their remarkable electrical conductivity,excellent chemical stability,wide band gap and tunable morphology.Both pure TMN and TMN-based materials have been extensively studied concerned with their preparation approaches,nanostructures,and favored performance in various applications.However,the processes towards synthesis of TMN are numerous and complex.Choosing appropriate method to obtain target TMN with desired structure is crucial,which further affects its practical application performance.Herein,this review offers a timely and comprehensive summary of the synthetic ways to TMN and their application in energy related domains.The synthesis section is categorized into in-situ and ex-situ based on where the N element in TMN origins from.Then,overviews on the energy related applications including energy storage,electrocatalysis and photocatalysis are discussed.In the end,the problems to be solved and the development trend of the synthesis and application of transition metal nitrides are prospected.