Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al2O3composi...Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al2O3composite materials were synthesized by one-step synthesis method. The chemical composition, morphology, structure, and thermal properties were investigated by XRD, EDS, SEM, and DSC. The results show that NaCl can be absorbed by Al2O3particle from 800 to 900 ℃ for Al2O3particle surface is rich active structure. The results also indicate that the leakage of NaCl when the phase change can be prevented by Al2O3particles and the enthalpy of phase change of NaCl-Al2O3material is 362 J/g. The composites have an excellent heat storage capacity. Therefore, this study contributes to one new thought and method to prepare high temperature heat storage material and this material can be applied in future thermal engineering.展开更多
Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in poly...Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.展开更多
This paper is a brief and selective review on hydrothermal synthesis of advanced materials. Some general comments about the hydrothermal synthesis of materials are presented. In particular, the surface modification an...This paper is a brief and selective review on hydrothermal synthesis of advanced materials. Some general comments about the hydrothermal synthesis of materials are presented. In particular, the surface modification and hydrothermal synthesis of functional powders (e.g. the hydrothermal coating of aluminum borate whiskers with chromium oxide, hydrothermal synthesis of Ni-Zn ferrite and magnesium hydroxide ) are introduced and their importance are explained.展开更多
Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperatur...Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.展开更多
Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide(CTAB)as template.The effect of several factors on surface a...Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide(CTAB)as template.The effect of several factors on surface area of products also had been discussed.The products were characterized by FT- IR,HRTEM and N 2 adsorption and desorption isotherm plot methods.There was typical structure as Si-O,Si- OH and Si-O-Si of mesoporous materials in the framework of synthesized materials;the pore size distributions of the products showed a sharp peak at 3.82 nm.The effect of hydrothermal treatment time and the amount of template on the specific surface area of mesoporous materials was important,when the Surf/Si=0.135,and hydrothermal time=12 h,and the surface area of the product reached up to 1 070 m2/g,which was higher than other products.展开更多
Fe-based alloy coatings containing TiB2–TiN –(h-BN) were synthesized in situ on Q235 steel substrates by a plasma cladding process using the powders of Fe901 alloy, Ti, and h-BN as raw materials. The effects of Ti...Fe-based alloy coatings containing TiB2–TiN –(h-BN) were synthesized in situ on Q235 steel substrates by a plasma cladding process using the powders of Fe901 alloy, Ti, and h-BN as raw materials. The effects of Ti/h-BN mass ratio on interfacial bonds between the coating and substrate along with the microstructures and microhardnesses of the coatings were investigated. The results show that the Ti/h-BN mass ratio is a vital factor in the formation of the coatings. Free h-BN can be introduced into the coatings by adding an excess amount of h-BN into the precursor. Decreases in the Ti/h-BN mass ratio improve the microstructural uniformity and compactness and enhance the interfacial bonds of the coatings. At a Ti/h-BN mass ratio of 10/20, the coating is free of cracks and micropores, and mainly consists of Fe-Cr, Fe3B, TiB2, TiN, Ti2N, TiB, FeN, FeB, Fe2B, and h-BN phases. Its average microhardness in the zone between 0.1–2.8 mm from the coating surface is about Hv0.2 551.5.展开更多
Micro/nano metal–organic frameworks(MOFs)have attracted significant attention in recent years due to their numerous unique properties,with many synthetic methods and strategies being reported for constructing MOFs wi...Micro/nano metal–organic frameworks(MOFs)have attracted significant attention in recent years due to their numerous unique properties,with many synthetic methods and strategies being reported for constructing MOFs with specific micro/nano structures.In addition,the design of micro/nano MOFs for energy storage and conversion applications and the study of the structure–activity relationship have also become research hotspots.Herein,a comprehensive overview of the recent progress on micro/nano MOFs is presented.We begin with a brief introduction to the various synthesis methods for controlling the morphology of micro/nano MOFs.Subsequently,the structure-dependent properties of micro/nano MOFs as electrode materials or catalysts in terms of batteries,supercapacitors,and catalysis are discussed.Finally,the remaining challenges and future perspectives in this field are presented.Overall,this review is expected to inspire the design of advanced micro/nano MOFs for efficient energy storage and conversion technologies.展开更多
Magnetic liquid can produce alternative internal pressure under the alternative high-frequency gradient magnetic field.Because it has higher bulk modulus,the internal pressure results in its volume change.Using piezoe...Magnetic liquid can produce alternative internal pressure under the alternative high-frequency gradient magnetic field.Because it has higher bulk modulus,the internal pressure results in its volume change.Using piezoelectric transducers,the ultrasonic wave generated by the vibration of magnetic liquids can be detected,which shows that the magnetic liquids have the magnetostrictive effect and can generate the ultrasonic vibration under the alternative magnetic gradient field.Some nonmagnetic abrasives and rust-proofing agents can be mixed into the magnetic liquids,under the alternative magnetic field,the abrasives held by magnetic liquids grind the surface of the workpieces,and thus,the finishing for the surface with complex shape,mold cavity and inner wall of tiny tubes can be realized.展开更多
The energy materials performance is intrinsically determined by structures from the average lattice structure to the atom arrangement, valence, and distribution of the containing transition metal(TM) elements. Underst...The energy materials performance is intrinsically determined by structures from the average lattice structure to the atom arrangement, valence, and distribution of the containing transition metal(TM) elements. Understanding the mechanism of the structure transition and atom rearrangement via synthesis or processing is key to expediting the exploration of excellent energy materials. In this work, in situ neutron scattering is employed to reveal the real-time structure evolution, including the TM-O bonds, lattice,TM valence and the migration of the high-voltage spinel cathode LiNi_(0.5)Mn_(1.5)O_(4). The transition-metalmediated spinel destabilization under the annealing at the oxygen-deficient atmosphere is pinpointed.The formation of Mn^(3+) is correlated to the TM migration activation, TM disordered rearrangement in the spinel, and the transition to a layered-rocksalt phase. The further TM interdiffusion and Mn^(3+) reduction are also revealed with multi-stage thermodynamics and kinetics. The mechanisms of phase transition and atom migrations as functions of temperature, time and atmosphere present important guidance on the synthesis in various-valence element containing oxides.展开更多
Hexagonal GaN films were prepared by nitriding Ga_2O_3 films with flowingammonia. Ga_2O_3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.)magnetron sputtering. This paper have investig...Hexagonal GaN films were prepared by nitriding Ga_2O_3 films with flowingammonia. Ga_2O_3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.)magnetron sputtering. This paper have investigated the change of structural properties of GaN filmsnitrided in NH_3 atmosphere at the temperatures of 850, 900, and 950 deg C for 15 min and nitridedat the temperature of 900 deg C for 10, 15, and 20 min, respectively. X-ray diffraction (XRD),scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectronspectroscopy (XPS) were used to analyze the structure, surface morphology and composition ofsynthesized samples. The results reveal that the as-grown films are polycrystalline GaN withhexagonal wurtzite structure and GaN films with the highest crystal quality can be obtained whennitrided at 900 deg C for 15 min.展开更多
Utilizing two polycarboxylic acids as primary ligands and 1,10-phenanthrolion as an auxiliary ligand in the existence of lanthanide nitrates, two lanthanide-based complexes formulated as [Nd4(2,6-pydc OH)6(Phen)4...Utilizing two polycarboxylic acids as primary ligands and 1,10-phenanthrolion as an auxiliary ligand in the existence of lanthanide nitrates, two lanthanide-based complexes formulated as [Nd4(2,6-pydc OH)6(Phen)4(H2O)2](H2O)2(1) and [Yb2(mBDC)3(Phen)2]n(2)(2,6-H2 pydc OH = 4-hydroxypyridine-2,6-dicarboxylic acid, m-H_2BDC = isophthalic acid, Phen = 1,10-phenanthroline) have been solvothermally synthesized. They have been fully characterized by satisfactory elemental analysis, FT-IR spectra, TGA and single-crystal X-ray diffraction. Single-crystal X-ray diffraction study reveals that 1 has a zero-dimensional structure and 2 exhibits a rare cds topological net structure. Compounds 1 and 2 exhibit strong characteristic emissions of Nd(Ⅲ) and Yb(Ⅲ) ions in the near-infrared(NIR) region.展开更多
Simple solvothermal reaction of PbI2,1,4-diazabicyclo[2.2.2]octane and benzyl alcohol in the presence of HI acid creates a new organically templated iodoplumbate hybrid:[(N-Bz-DABCO)(PbI3)]n(1,N-Bz-DABCO+ = N-b...Simple solvothermal reaction of PbI2,1,4-diazabicyclo[2.2.2]octane and benzyl alcohol in the presence of HI acid creates a new organically templated iodoplumbate hybrid:[(N-Bz-DABCO)(PbI3)]n(1,N-Bz-DABCO+ = N-benzyl-1,4-diazabicyclo[2.2.2]octane).Compound 1 crystallizes in orthorhombic space group P212121 with a = 20.044(9),b = 8.002(3),c = 12.345(5) ?,V = 1980.1(14) A3,Z = 4,C(13)H(19)N2PbI3,Mr = 791.19,Dc = 2.654 g/cm^3,F(000) = 1408,μ(Mo Kα) = 13.189 mm–1,the final R = 0.0303 and w R = 0.0849 for 3777 observed reflections(I 〉 2σ(I)).Compound 1 contains one-dimensional anionic [PbI3]nn-chains that are enclosed into the cationic channel formed from the N-benzyl-1,4-diazabicyclo[2.2.2]octane.Noteworthy,compared with common symmetrical N,N?-dialkyl-DABCO^(2+) cations,in-situ formed asymmetrical N-monoalkyl-DABCO~+ cation is first used as structure directing agents/templating agents in the haloplumbate system,finally leading to the occurrence of noncentrosymmetric feature in compound 1.In addition,UV-Vis absorption spectrum analysis reveals that compound 1 is a potential semiconductor material with energy gap of 2.80 eV.展开更多
This is a part of our systematic research work on polyimides with mesogenic unit side chain. In this study, a new 4'-phenylpbenyl 4-(3",5"-diaminobenzoyloxy)benzoate and polyimide were synthesized, and characteri...This is a part of our systematic research work on polyimides with mesogenic unit side chain. In this study, a new 4'-phenylpbenyl 4-(3",5"-diaminobenzoyloxy)benzoate and polyimide were synthesized, and characterized by FTIR, ^1H-NMR, inherent viscosity, mechanical properties, and solubility measurements. The diamine composed with mesogenic unit aryl ester groups and bipbenyl group with longer L/D ratio, was synthesized by two key steps. Firstly, the hydroxy group of 4-hydroxybenzoic acid was protected by acetoxy group for avoiding self- polymerization of 4-hydroxybenzoic acid, and then selectively hydrolyzed after esterification of carboxyl. Secondly, a selective catalysis hydrogenation was adopted to prevent the aryl ester from deoxidation. Based on this diamine, a novel polyimide was prepared by polycondensation of 4'-phenylphenyl 4-(3", 5"-diaminobenzoyloxy)benzoate and 4-aminophenyl ether(ODA) with 4, 4'-oxydiphthalic anhydride(ODPA) in N-methyl-2-pyrrolidone (NMP). The resulting polyimide with longer side chain showed better solubility and more regular structure. Its inherent viscosity is lower than that without side chains, but its modulus and strength not only maintained, even improved.展开更多
Development of next generation batteries requires a breakthrough in materials.Traditional one-by-one method,which is suitable for synthesizing large number of sing-composition material,is timeconsuming and costly.High...Development of next generation batteries requires a breakthrough in materials.Traditional one-by-one method,which is suitable for synthesizing large number of sing-composition material,is timeconsuming and costly.High throughput and combinatorial experimentation,is an effective method to synthesize and characterize huge amount of materials over a broader compositional region in a short time,which enables to greatly speed up the discovery and optimization of materials with lower cost.In this work,high throughput and combinatorial materials synthesis technologies for lithium ion battery research are discussed,and our efforts on developing such instrumentations are introduced.展开更多
Water constitutes the largest energy carrier on earth,absorbing more than 70%of the solar energy received by the earth's surface,yet its low exploitation has been a constant concern.The hydrovoltaic effect is an e...Water constitutes the largest energy carrier on earth,absorbing more than 70%of the solar energy received by the earth's surface,yet its low exploitation has been a constant concern.The hydrovoltaic effect is an emerging technology that generates electricity through the direct interaction between nanomaterials and water of various forms(raindrops,waves,flows,moisture,and natural evaporation).Especially,the evaporation-driven hydrovoltaic effect is a spontaneous and ubiquitous process that can directly convert thermal energy from the surrounding environment into electricity without the demand for additional mechanical work,which shows unique advantages compared with other hydrovoltaic effects.A variety of nanostructured materials have been steadily developed for evaporation-driven hydrovoltaic devices(EHDs)in recent years.However,there has been a lack of a clear specification on the selection and design of materials for improving device performance.Herein,we first analyze the mechanisms of EHDs followed by a summarization of the recent advances in materials,including carbon materials,biomass-based materials,metal oxides,composite materials,and others.We then discuss the strategies for improving the energy conversion efficiency and the output power in terms of structural design,surface modification,and interface treatment.Finally,we provide an outlook on the potential applications of electricity generation,sensors,and desalination technology,as well as the challenges and prospects for the development of this emerging technology in the future.展开更多
Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for ...Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for synthesizing high- quality cesium lead halide perovskite (CsPbX3, X = CI, Br, and I or C1/Br and I/Br) nanocrystals (NCs) by direct heating of precursors in octadecene in air. Experimental results show that the particle size and composition of as-prepared CsPbX3 nanocrystals can be successfully tuned by a simple variation of reaction temperature. The emission peak positions of the as-prepared nanocrystals can be conveniently tuned from the UV to the NIR (360-700 nm) region, and the quantum yield of the as-obtained samples (green and red emissions) can reach up to 87%. The structures and chemical compositions of the as-obtained NCs were characterized by transmission electron microscopy, X-ray diffraction, and elemental analysis. This proposed synthetic route can yield large amounts of high-quality NCs with a one-batch reaction, usually on the gram scale, and could pave the way for further applications of perovskite-based light-emitting and photovoltaic solar cells.展开更多
Two-dimensional(2D) materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride(2D hBN),a...Two-dimensional(2D) materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride(2D hBN),an insulator with excellent thermal stability,chemical inertness,and unique electronic and optical properties,and a band gap of 5.97 e V,is considered to be an ideal candidate for integration with other 2D materials.Nevertheless,the controllable growth of high-quality 2D h-BN is still a great challenge.A comprehensive overview of the progress that has been made in the synthesis of 2D h-BN is presented,highlighting the advantages and disadvantages of various synthesis approaches.In addition,the electronic,optical,thermal,and mechanical properties,heterostructures,and related applications of 2D h-BN are discussed.展开更多
Cerium-doped yttrium aluminum garnet(YAG:Ce) as a yellow phosphor for white light-emitting diodes(LEDs) was synthesized via a facile combustion method using Y2 O3, CeO2, Al2 O3, Al,and NaClO4 as raw materials. Th...Cerium-doped yttrium aluminum garnet(YAG:Ce) as a yellow phosphor for white light-emitting diodes(LEDs) was synthesized via a facile combustion method using Y2 O3, CeO2, Al2 O3, Al,and NaClO4 as raw materials. The combustion synthesis approach utilizes the strong exothermic oxidation of aluminum to realize a self-sustaining reaction. In this study, we investigated the effects of the ratios of Al2 O3 to AI,fluxes, and coprecipitated materials as raw materials on the luminescence properties of the synthesized YAG:Ce phosphors. When the amount of Al2 O3 x is varied, the combustion reaction proceeds at x ≤ 1.8,with x = 1.725 being the optimum condition for producing a high-performance product. When 5 wt%BaF2 is added, the luminescence intensity is significantly improved owing to a decrease of YAP(YAlO3)formation with improved uniformity. However, the addition of CaF2 and NaF does not improve the luminescence properties. To suppress the segregation of CeO2, we used the coprecipitated material Y2 O3-CeO2 as a raw material. Unlike with separate addition of Y2 O3 and CeO2, Ce ions are uniformly distributed in the coprecipitated material, resulting in improved luminescence properties. The combination of BaF2 and coprecipitated material significantly improves the internal quantum efficiency to83.0%, which is close to that of commercial phosphors.展开更多
Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol(DEG) used here plays dual role in synthesis ...Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol(DEG) used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction(XRD) and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.展开更多
In this paper, we report a simple one-step thermal reducing method for synthesis of bimetallic Au@Pd nanoparticles with core-shell structures on the graphene surface. This new type of Au@Pd-G composites is characteriz...In this paper, we report a simple one-step thermal reducing method for synthesis of bimetallic Au@Pd nanoparticles with core-shell structures on the graphene surface. This new type of Au@Pd-G composites is characterized by transmission electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. It is found that Au@Pd nanoparticles with an average diameter of 11 nm are well dispersed on the graphene surface, and the Au core quantity as well as the Pd shell thickness can be quantitatively controlled by loading different amounts of metallic precursors, and the involved core-shell structure formation mechanism is also discussed. The ternary Pt/Au@Pd-G composites can also be synthetized by the subsequent Pt doping. The catalytic performance of Au@Pd-G composites toward methanol electro-oxidation in acidic media is investigated. The results show that Au@Pd-G composites exhibit higher catalytic activity, better stability and stronger tolerance to CO poisoning than Pd-G and Au-G counterparts.展开更多
基金Funded by the National Natural Science of China(No.2012BAA05B06)
文摘Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al2O3composite materials were synthesized by one-step synthesis method. The chemical composition, morphology, structure, and thermal properties were investigated by XRD, EDS, SEM, and DSC. The results show that NaCl can be absorbed by Al2O3particle from 800 to 900 ℃ for Al2O3particle surface is rich active structure. The results also indicate that the leakage of NaCl when the phase change can be prevented by Al2O3particles and the enthalpy of phase change of NaCl-Al2O3material is 362 J/g. The composites have an excellent heat storage capacity. Therefore, this study contributes to one new thought and method to prepare high temperature heat storage material and this material can be applied in future thermal engineering.
文摘Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.
文摘This paper is a brief and selective review on hydrothermal synthesis of advanced materials. Some general comments about the hydrothermal synthesis of materials are presented. In particular, the surface modification and hydrothermal synthesis of functional powders (e.g. the hydrothermal coating of aluminum borate whiskers with chromium oxide, hydrothermal synthesis of Ni-Zn ferrite and magnesium hydroxide ) are introduced and their importance are explained.
文摘Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.
基金Funded by Social Development Plan of Jiangsu Department of the Science and Technology,Jiangsu,China(No.BS2007038)
文摘Mesoporous materials with the highest surface area were synthesized by hydrothermal treatment from coal-measure kaolin using cetyltrimethylammonium bromide(CTAB)as template.The effect of several factors on surface area of products also had been discussed.The products were characterized by FT- IR,HRTEM and N 2 adsorption and desorption isotherm plot methods.There was typical structure as Si-O,Si- OH and Si-O-Si of mesoporous materials in the framework of synthesized materials;the pore size distributions of the products showed a sharp peak at 3.82 nm.The effect of hydrothermal treatment time and the amount of template on the specific surface area of mesoporous materials was important,when the Surf/Si=0.135,and hydrothermal time=12 h,and the surface area of the product reached up to 1 070 m2/g,which was higher than other products.
基金financially supported by the Natural Science Foundation of Jiangsu Province, China (No.BK2011250)the Jiangsu Province Postdoctoral Science Foundation (No. 1101017C)+1 种基金the China Postdoctoral Science Foundation (No. 20100481079)the China Scholarship Council and Outstanding Innovative Talents Support Plan of Hohai University
文摘Fe-based alloy coatings containing TiB2–TiN –(h-BN) were synthesized in situ on Q235 steel substrates by a plasma cladding process using the powders of Fe901 alloy, Ti, and h-BN as raw materials. The effects of Ti/h-BN mass ratio on interfacial bonds between the coating and substrate along with the microstructures and microhardnesses of the coatings were investigated. The results show that the Ti/h-BN mass ratio is a vital factor in the formation of the coatings. Free h-BN can be introduced into the coatings by adding an excess amount of h-BN into the precursor. Decreases in the Ti/h-BN mass ratio improve the microstructural uniformity and compactness and enhance the interfacial bonds of the coatings. At a Ti/h-BN mass ratio of 10/20, the coating is free of cracks and micropores, and mainly consists of Fe-Cr, Fe3B, TiB2, TiN, Ti2N, TiB, FeN, FeB, Fe2B, and h-BN phases. Its average microhardness in the zone between 0.1–2.8 mm from the coating surface is about Hv0.2 551.5.
基金This work was financially supported by the National Natural Science Foundation of China(NSFC-U1904215,22205196)the Natural Science Foundation of Jiangsu Province(BK20210790)the start-up fundings from Yangzhou University.
文摘Micro/nano metal–organic frameworks(MOFs)have attracted significant attention in recent years due to their numerous unique properties,with many synthetic methods and strategies being reported for constructing MOFs with specific micro/nano structures.In addition,the design of micro/nano MOFs for energy storage and conversion applications and the study of the structure–activity relationship have also become research hotspots.Herein,a comprehensive overview of the recent progress on micro/nano MOFs is presented.We begin with a brief introduction to the various synthesis methods for controlling the morphology of micro/nano MOFs.Subsequently,the structure-dependent properties of micro/nano MOFs as electrode materials or catalysts in terms of batteries,supercapacitors,and catalysis are discussed.Finally,the remaining challenges and future perspectives in this field are presented.Overall,this review is expected to inspire the design of advanced micro/nano MOFs for efficient energy storage and conversion technologies.
基金Sponsored by Zhejiang Province Scientific and Technological Key Task Program (2007C21025)Ningbo Science and Technological Key Task Program (2007B10010)
文摘Magnetic liquid can produce alternative internal pressure under the alternative high-frequency gradient magnetic field.Because it has higher bulk modulus,the internal pressure results in its volume change.Using piezoelectric transducers,the ultrasonic wave generated by the vibration of magnetic liquids can be detected,which shows that the magnetic liquids have the magnetostrictive effect and can generate the ultrasonic vibration under the alternative magnetic gradient field.Some nonmagnetic abrasives and rust-proofing agents can be mixed into the magnetic liquids,under the alternative magnetic field,the abrasives held by magnetic liquids grind the surface of the workpieces,and thus,the finishing for the surface with complex shape,mold cavity and inner wall of tiny tubes can be realized.
基金supported by the Division of Materials Science and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy (DOE)。
文摘The energy materials performance is intrinsically determined by structures from the average lattice structure to the atom arrangement, valence, and distribution of the containing transition metal(TM) elements. Understanding the mechanism of the structure transition and atom rearrangement via synthesis or processing is key to expediting the exploration of excellent energy materials. In this work, in situ neutron scattering is employed to reveal the real-time structure evolution, including the TM-O bonds, lattice,TM valence and the migration of the high-voltage spinel cathode LiNi_(0.5)Mn_(1.5)O_(4). The transition-metalmediated spinel destabilization under the annealing at the oxygen-deficient atmosphere is pinpointed.The formation of Mn^(3+) is correlated to the TM migration activation, TM disordered rearrangement in the spinel, and the transition to a layered-rocksalt phase. The further TM interdiffusion and Mn^(3+) reduction are also revealed with multi-stage thermodynamics and kinetics. The mechanisms of phase transition and atom migrations as functions of temperature, time and atmosphere present important guidance on the synthesis in various-valence element containing oxides.
基金This work was financially supported by the Science Research Foundation of Shandong Jiaotong University (No. Z200503) and the National Natural Science Foundation of China (No. 90301002).
文摘Hexagonal GaN films were prepared by nitriding Ga_2O_3 films with flowingammonia. Ga_2O_3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.)magnetron sputtering. This paper have investigated the change of structural properties of GaN filmsnitrided in NH_3 atmosphere at the temperatures of 850, 900, and 950 deg C for 15 min and nitridedat the temperature of 900 deg C for 10, 15, and 20 min, respectively. X-ray diffraction (XRD),scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectronspectroscopy (XPS) were used to analyze the structure, surface morphology and composition ofsynthesized samples. The results reveal that the as-grown films are polycrystalline GaN withhexagonal wurtzite structure and GaN films with the highest crystal quality can be obtained whennitrided at 900 deg C for 15 min.
基金supported by the National Basic Research Program of China(973 Program,2012CB821702)the National Natural Science Foundation of China(21233009 and 21571175)the State Key Laboratory of Structural Chemistry
文摘Utilizing two polycarboxylic acids as primary ligands and 1,10-phenanthrolion as an auxiliary ligand in the existence of lanthanide nitrates, two lanthanide-based complexes formulated as [Nd4(2,6-pydc OH)6(Phen)4(H2O)2](H2O)2(1) and [Yb2(mBDC)3(Phen)2]n(2)(2,6-H2 pydc OH = 4-hydroxypyridine-2,6-dicarboxylic acid, m-H_2BDC = isophthalic acid, Phen = 1,10-phenanthroline) have been solvothermally synthesized. They have been fully characterized by satisfactory elemental analysis, FT-IR spectra, TGA and single-crystal X-ray diffraction. Single-crystal X-ray diffraction study reveals that 1 has a zero-dimensional structure and 2 exhibits a rare cds topological net structure. Compounds 1 and 2 exhibit strong characteristic emissions of Nd(Ⅲ) and Yb(Ⅲ) ions in the near-infrared(NIR) region.
基金financially supported by the Natural Scientific Foundation of Lvliang University(No.ZRXN201603)the characteristic&preponderant discipline of“1331 engineering”of Shanxi Province,Materials Science and Engineering(2050205 higher education)
文摘Simple solvothermal reaction of PbI2,1,4-diazabicyclo[2.2.2]octane and benzyl alcohol in the presence of HI acid creates a new organically templated iodoplumbate hybrid:[(N-Bz-DABCO)(PbI3)]n(1,N-Bz-DABCO+ = N-benzyl-1,4-diazabicyclo[2.2.2]octane).Compound 1 crystallizes in orthorhombic space group P212121 with a = 20.044(9),b = 8.002(3),c = 12.345(5) ?,V = 1980.1(14) A3,Z = 4,C(13)H(19)N2PbI3,Mr = 791.19,Dc = 2.654 g/cm^3,F(000) = 1408,μ(Mo Kα) = 13.189 mm–1,the final R = 0.0303 and w R = 0.0849 for 3777 observed reflections(I 〉 2σ(I)).Compound 1 contains one-dimensional anionic [PbI3]nn-chains that are enclosed into the cationic channel formed from the N-benzyl-1,4-diazabicyclo[2.2.2]octane.Noteworthy,compared with common symmetrical N,N?-dialkyl-DABCO^(2+) cations,in-situ formed asymmetrical N-monoalkyl-DABCO~+ cation is first used as structure directing agents/templating agents in the haloplumbate system,finally leading to the occurrence of noncentrosymmetric feature in compound 1.In addition,UV-Vis absorption spectrum analysis reveals that compound 1 is a potential semiconductor material with energy gap of 2.80 eV.
基金We are grateful to the National Natural Science Foundation of China for financial support(project No.20274026)
文摘This is a part of our systematic research work on polyimides with mesogenic unit side chain. In this study, a new 4'-phenylpbenyl 4-(3",5"-diaminobenzoyloxy)benzoate and polyimide were synthesized, and characterized by FTIR, ^1H-NMR, inherent viscosity, mechanical properties, and solubility measurements. The diamine composed with mesogenic unit aryl ester groups and bipbenyl group with longer L/D ratio, was synthesized by two key steps. Firstly, the hydroxy group of 4-hydroxybenzoic acid was protected by acetoxy group for avoiding self- polymerization of 4-hydroxybenzoic acid, and then selectively hydrolyzed after esterification of carboxyl. Secondly, a selective catalysis hydrogenation was adopted to prevent the aryl ester from deoxidation. Based on this diamine, a novel polyimide was prepared by polycondensation of 4'-phenylphenyl 4-(3", 5"-diaminobenzoyloxy)benzoate and 4-aminophenyl ether(ODA) with 4, 4'-oxydiphthalic anhydride(ODPA) in N-methyl-2-pyrrolidone (NMP). The resulting polyimide with longer side chain showed better solubility and more regular structure. Its inherent viscosity is lower than that without side chains, but its modulus and strength not only maintained, even improved.
文摘Development of next generation batteries requires a breakthrough in materials.Traditional one-by-one method,which is suitable for synthesizing large number of sing-composition material,is timeconsuming and costly.High throughput and combinatorial experimentation,is an effective method to synthesize and characterize huge amount of materials over a broader compositional region in a short time,which enables to greatly speed up the discovery and optimization of materials with lower cost.In this work,high throughput and combinatorial materials synthesis technologies for lithium ion battery research are discussed,and our efforts on developing such instrumentations are introduced.
基金National Key Research and Development Program of China,Grant/Award Number:2019YFA0705400The Fundamental Research Funds for the Central Universities,Grant/Award Number:NJ202202+1 种基金The Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures,Grant/Award Number:MCMS-I-0421K01Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20212008。
文摘Water constitutes the largest energy carrier on earth,absorbing more than 70%of the solar energy received by the earth's surface,yet its low exploitation has been a constant concern.The hydrovoltaic effect is an emerging technology that generates electricity through the direct interaction between nanomaterials and water of various forms(raindrops,waves,flows,moisture,and natural evaporation).Especially,the evaporation-driven hydrovoltaic effect is a spontaneous and ubiquitous process that can directly convert thermal energy from the surrounding environment into electricity without the demand for additional mechanical work,which shows unique advantages compared with other hydrovoltaic effects.A variety of nanostructured materials have been steadily developed for evaporation-driven hydrovoltaic devices(EHDs)in recent years.However,there has been a lack of a clear specification on the selection and design of materials for improving device performance.Herein,we first analyze the mechanisms of EHDs followed by a summarization of the recent advances in materials,including carbon materials,biomass-based materials,metal oxides,composite materials,and others.We then discuss the strategies for improving the energy conversion efficiency and the output power in terms of structural design,surface modification,and interface treatment.Finally,we provide an outlook on the potential applications of electricity generation,sensors,and desalination technology,as well as the challenges and prospects for the development of this emerging technology in the future.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21373097 and 51072067).
文摘Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for synthesizing high- quality cesium lead halide perovskite (CsPbX3, X = CI, Br, and I or C1/Br and I/Br) nanocrystals (NCs) by direct heating of precursors in octadecene in air. Experimental results show that the particle size and composition of as-prepared CsPbX3 nanocrystals can be successfully tuned by a simple variation of reaction temperature. The emission peak positions of the as-prepared nanocrystals can be conveniently tuned from the UV to the NIR (360-700 nm) region, and the quantum yield of the as-obtained samples (green and red emissions) can reach up to 87%. The structures and chemical compositions of the as-obtained NCs were characterized by transmission electron microscopy, X-ray diffraction, and elemental analysis. This proposed synthetic route can yield large amounts of high-quality NCs with a one-batch reaction, usually on the gram scale, and could pave the way for further applications of perovskite-based light-emitting and photovoltaic solar cells.
基金Project supported by the National Natural Science Foundation of China(Nos.61376007,61674137)the National Key Research and Development Program of China(No.2016YFB0400802)
文摘Two-dimensional(2D) materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride(2D hBN),an insulator with excellent thermal stability,chemical inertness,and unique electronic and optical properties,and a band gap of 5.97 e V,is considered to be an ideal candidate for integration with other 2D materials.Nevertheless,the controllable growth of high-quality 2D h-BN is still a great challenge.A comprehensive overview of the progress that has been made in the synthesis of 2D h-BN is presented,highlighting the advantages and disadvantages of various synthesis approaches.In addition,the electronic,optical,thermal,and mechanical properties,heterostructures,and related applications of 2D h-BN are discussed.
基金supported by the"Nanotechnology Platform"Program of the Ministry of Education,Culture,Sports,Science and Technology of Japan(MEXT)
文摘Cerium-doped yttrium aluminum garnet(YAG:Ce) as a yellow phosphor for white light-emitting diodes(LEDs) was synthesized via a facile combustion method using Y2 O3, CeO2, Al2 O3, Al,and NaClO4 as raw materials. The combustion synthesis approach utilizes the strong exothermic oxidation of aluminum to realize a self-sustaining reaction. In this study, we investigated the effects of the ratios of Al2 O3 to AI,fluxes, and coprecipitated materials as raw materials on the luminescence properties of the synthesized YAG:Ce phosphors. When the amount of Al2 O3 x is varied, the combustion reaction proceeds at x ≤ 1.8,with x = 1.725 being the optimum condition for producing a high-performance product. When 5 wt%BaF2 is added, the luminescence intensity is significantly improved owing to a decrease of YAP(YAlO3)formation with improved uniformity. However, the addition of CaF2 and NaF does not improve the luminescence properties. To suppress the segregation of CeO2, we used the coprecipitated material Y2 O3-CeO2 as a raw material. Unlike with separate addition of Y2 O3 and CeO2, Ce ions are uniformly distributed in the coprecipitated material, resulting in improved luminescence properties. The combination of BaF2 and coprecipitated material significantly improves the internal quantum efficiency to83.0%, which is close to that of commercial phosphors.
基金the Council of Scientific and Industrial Research, India for the award of senior research fellowship (File. 09/1077/(0001)/ 2012/EMR-1)
文摘Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol(DEG) used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction(XRD) and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.
基金supported by the PAPD (No.50831004)the Innovation Fund of Jiangsu Province (No.BY2013072-06)+2 种基金the Natural Science Foundation of Jiangsu Province (No.2012729)the National Natural Science Foundation of China (No.51171078,11374136)the State Key Program for Basic Research of China (No.2010CB631004)
文摘In this paper, we report a simple one-step thermal reducing method for synthesis of bimetallic Au@Pd nanoparticles with core-shell structures on the graphene surface. This new type of Au@Pd-G composites is characterized by transmission electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. It is found that Au@Pd nanoparticles with an average diameter of 11 nm are well dispersed on the graphene surface, and the Au core quantity as well as the Pd shell thickness can be quantitatively controlled by loading different amounts of metallic precursors, and the involved core-shell structure formation mechanism is also discussed. The ternary Pt/Au@Pd-G composites can also be synthetized by the subsequent Pt doping. The catalytic performance of Au@Pd-G composites toward methanol electro-oxidation in acidic media is investigated. The results show that Au@Pd-G composites exhibit higher catalytic activity, better stability and stronger tolerance to CO poisoning than Pd-G and Au-G counterparts.