Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts...Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts.TMPs have been produced in various morphologies,including hollow and porous nanostructures,which are features deemed desirable for electrocatalytic materials.Templated synthesis routes are often responsible for such morphologies.This paper reviews the latest advances and existing challenges in the synthesis of TMP-based OER and HER catalysts through templated methods.A comprehensive review of the structure-property-performance of TMP-based HER and OER catalysts prepared using different templates is presented.The discussion proceeds according to application,first by HER and further divided among the types of templates used-from hard templates,sacrificial templates,and soft templates to the emerging dynamic hydrogen bubble template.OER catalysts are then reviewed and grouped according to their morphology.Finally,prospective research directions for the synthesis of hollow and porous TMP-based catalysts,such as improvements on both activity and stability of TMPs,design of environmentally benign templates and processes,and analysis of the reaction mechanism through advanced material characterization techniques and theoretical calculations,are suggested.展开更多
Transparent Al_(2)O_(3) ceramics with grains aligned to the c-axis were prepared by adding platelets with a low aspect ratio into fine equiaxed particles.The mixed powders were formed into green bodies using spontaneo...Transparent Al_(2)O_(3) ceramics with grains aligned to the c-axis were prepared by adding platelets with a low aspect ratio into fine equiaxed particles.The mixed powders were formed into green bodies using spontaneous coagulation casting and sintered by pressureless sintering and hot-isostatic pressure sintering.Zeta potentials and rheological behavior of the slurries,relative densities of green bodies,and orientation and optical properties of sintered bodies were investigated and discussed.The platelet with a high aspect ratio suppressed densification more seriously during sintering than the one with a low aspect ratio.An excellent oriented structure was obtained when 5 wt%platelets with a low aspect ratio were added,and transparent Al_(2)O_(3) ceramics with grains aligned to c-axis were successfully prepared;the in-line transmittance was 78.4%at 600 nm,which is the highest one in the currently reported literature.展开更多
The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and h...The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the first time. The change of template structure after doping and the stability origin of dual-doped system are characterized by small angle X-ray scattering and polarized optical microscopy. Results show that the interaction and space matching between surfactant bilayers and doped particles are key factors to obtain stable hybrid.展开更多
Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution...Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution of uranyl nitrate, phosphite acid and their respective organic ammonium hydroxids. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared and fluorescence spectroscopy. In 1, pentagonal [UO7] bipyramids share comers with three [HPO3]2- tetrahedra and one edge with a [NO3]- anion to form [（UO2）- （HPO3）（NO3）]^- ladder-like chains parallel to the b axis. The structure of 2 is also based upon one-dimensional anionic [（UO2）2（H2PO3）2（HPO3）（NO3）2]2-chains of comer-sharing penta- gonal [UOT] bipyramids with [H2PO3]- and [HPO3] tetrahedra, which is still unknown in structural chemistry of uranium so far. Crystal data for 1： monoclinic, space group C2/m, a = 21.808（7）, b = 6.9605（15）, c = 8.357（2） A, β = 98.327（15）°, V= 1255.2（6） A^3, Z = 4, Dc = 2.573 g/cm^3, F（000） = 888, μ = 13.086 mm^-1 the final R = 0.0418 and wR = 0.0906 （I 〉 2σ（I））; and those for 2： monoclinic, space group C2/c, a = 36.4549（8）, b = 14.5296（11）, c = 20.8253（11） A, β = 101.7440（8）°, V= 10799.7（10） A3, Z = 8, Dc= 1.711 g/cm^3, F（000） = 5424,μ = 6.144 mm^-1, the final R= 0.0368 and wR= 0.0865 （I〉 2σ（I））.展开更多
Two new nonmetal borates, [（C2H10N2）]2[B14O20（OH）6] 1 and [C8H22N4][B5O6（OH）4]2 2, have been synthesized under mild conditions and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis and ...Two new nonmetal borates, [（C2H10N2）]2[B14O20（OH）6] 1 and [C8H22N4][B5O6（OH）4]2 2, have been synthesized under mild conditions and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis and thermogravimetric analysis. Crystal data for compound 1： triclinic, space group P^-1, a = 8.4979（17）, b = 8.8498（18）, c = 10.065（2）A^°, α = 95.01（3）, β = 96.99（3）, γ = 116.82（3）°, V= 661.8（3）A^°^3, Z= 1, Mr = 697.63, Dc = 1.751 g/cm^3,μ = 0.163 mm^-1, F（000） = 356, the final R = 0.0372 and wR = 0.0968 （I 〉 2σ（I））; and those for compound 2： monoclinic, space group P21/c, a = 9.1867（18）, b= 14.118（3）, c = 10.334（2）A^°, β = 91.48（3）°, V = 1339.8（5）A^°^3, Z = 2, Mr = 610.46, Dc = 1.513 g/cm^3,μ = 0.135 mm^-1, F（000） = 632, the final R = 0.0350 and wR = 0.0912 （I 〉 2σ（I））. For both 1 and 2, the anionic units are interlinked via O-H…O hydrogen bonds to form a 3D supramolecular network, while the protonated cations are located in the free space of the inorganic borate framework and interact with the anions by electrostatic attraction and extensive N-H…O hydrogen bonds.展开更多
Enhanced piezoelectric response was usually achieved in(Bi_(0.5) Na_(0.5))TiO_(3)(BNT)-based ceramics with sacrifice of depolarization temperature T_(d),seriously limiting their usage range in electromechanical applic...Enhanced piezoelectric response was usually achieved in(Bi_(0.5) Na_(0.5))TiO_(3)(BNT)-based ceramics with sacrifice of depolarization temperature T_(d),seriously limiting their usage range in electromechanical applications.In this work,we propose to explore piezoelectric anisotropy and domain engineering in compositionµstructure-controlled textured ceramics to resolve this issue.[001]c-textured 0.94(Bi_(0.5) Na_(0.5))TiO_(3)–0.06BaTiO_(3)(0.94BNT-0.06BT)ceramics with Lotgering factor F_(001)-91% were fabricated through homoepitaxial templated grain growth(TGG)via using 0.94BNT-0.06BT microplatelet templates.The textured samples exhibited more ordered domains with facilitated domain switching behavior,being consistent with saturated high polarization achieved at lower electric fields.Increasing F_(001) to above 60%enables rapid enhancement of piezoelectric response.Notably,compared to non-textured counterpart,the maximally textured ceramics exhibited-236%enhanced piezoelectric coefficient(d_(33)-302 pC/N)and-280% enhanced piezoelectric voltage coefficient(g_(33)-49.8×10^(−3)Vm/N),together with slightly increased depolarization temperature(T_(d)-106℃).Moreover,those values are approaching or even higher than the single-crystal values.This work not only provides important guidelines for design and synthesis of novel textured ceramics with improved comprehensive electrical properties,but also can expand application fields of BNT-based ceramics.展开更多
Covalent organic frameworks(COFs), as highly tunable porous crystalline materials, have promising applications in potassium-ion batteries(PIBs) due to their abundant charge carrier transport channels and excellent str...Covalent organic frameworks(COFs), as highly tunable porous crystalline materials, have promising applications in potassium-ion batteries(PIBs) due to their abundant charge carrier transport channels and excellent structural stability. However, the excessive stacking of interlayer electron clouds makes it difficult to expose internal active sites. Strategies to design functional COFs with controllable morphology and copious active sites are promising but still challenging. Herein, by utilizing the condensation between1,3,5-triformylbenzene(TFB) and p-phenylenediamine(PPD) and using amino-modified SiO_(2) nanospheres as templates, we synthesize core-shell NH_(2)-SiO_(2)@TP-COF. Through NaOH etching of NH_(2)-SiO_(2)@TP-COF, we obtain imine-based TP-COF hollow nanospheres, which shows excellent potassium storage performance when applied to the anode for PIBs. Ex-situ analysis and density functional theory calculations reveal that C=N groups and benzenes are active sites for K^(+) storage.展开更多
Various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrod...Various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrodeposition. These structures occur if the electroplating is continued after the nanowires appear on the membrane surface. By varying the membrane ge- ometry, pulse current electroplating parameters, and alternating electrodeposition from two baths composed of a variety of electrolytes, diverse models were fabricated, including a hollow container with a wall thickness of 10 nm 20 nm. This biomimetic method suggests an analogy between the shape-forming processes of plants and their metallic models. Nanostruc- tured mesostructures of various metals （Ag, Pd, Ni）, alloys （PdNi, Pbln） and hybrid structures .（PdNi/Pb, PdNi/Pbln） were obtained. They can be of interest for fundamental research （self-assembly, morphogenesis） as well as for applications in nanotechnology （catalysis, nanoplasmonics, medicine, superhydrophobic surfaces）.展开更多
In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption ch...In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption characterization technologies. The high-pressure hydrogen uptake performance was analyzed using standard Pressure-Composition-Temperature apparatus in order to study the pore size effects on hydrogen uptake. These as-obtained porous carbons showed different characteristics of pore size distribution as well as specific surface area. The results indicate that the most effective pores for adsorbing hydrogen depended on the storage pressure. These ultramicropores （0.65-0.85 nm） could be the most effective pores on excess H2 uptake at 1 bar, however, micropores （0.85-2 nm） would play a more important role in excess H2 uptake at higher pressure at 77 K. At room temperature, pore size effects on H2 uptake capacity were very weak. Both specific surface area and total pore volume play more important roles than pore size for H2 uptake at room temperature, which was clearly different from that at 77 K. For applications in future, the corncob-derived activated carbons can be more available than zeolite templated carbons at 77 K. Element doping enhanced hydrogen uptake could be main research direction for improving H2 uptake capacity at room temperature.展开更多
Titanium dioxide was deposited from aqueous suspension onto cellulosic surfaces. Titania was sourced from Degussa （P25TM, 70：30 anatase：rutile）. Dry uptake of particles was shown to be rapid and dominant with one-...Titanium dioxide was deposited from aqueous suspension onto cellulosic surfaces. Titania was sourced from Degussa （P25TM, 70：30 anatase：rutile）. Dry uptake of particles was shown to be rapid and dominant with one-third of the deposition occurring in less than 30 s and over one-half in the first minute. Isotherms were recorded to compare the rate of titanium deposition on dry and pre-wetted cotton. In the dry case uptake reached a maximum in 30 min whereas in the pre-wetted case the uptake was seen to continue beyond 180 min. A broad trend of higher deposition occurring at lower pH was seen, corresponding to the region where surface charges were opposite and thus attractive. Dry pickup was less significant at high pH. The response to varying ionic strength was complex and was attributed to the combined effect of charge screening, particle aggregation and consequent particle entrapment or occlusion. Titania deposition into the interstices of woven cotton sheets resulted in the formation of inorganic, nanoparticulate skeletons which could be isolated by controlled combustion of the cellulose and thus cotton was suggested to have potential for the templated synthesis of high surface area semiconductor materials.展开更多
A novel macrolactonization method was developed using a chiral β-lactam as the template. This novel method features that the macrocyclization is simultaneously achieved while a TBS protected hydroxy group is deprotec...A novel macrolactonization method was developed using a chiral β-lactam as the template. This novel method features that the macrocyclization is simultaneously achieved while a TBS protected hydroxy group is deprotected.展开更多
Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission ele...Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N 2 adsorption-desorption suggest that the nanocasted MIOs are synthetic hematite（α-Fe2O3） with a wormhole-like mesoporous network.As（V） adsorption test shows that the selected MIO—MIO-500（calcinated at 500 °C） with a BET surface area of 82 m^ 2 /g has a maximum adsorption capacity of 5.39 mg/g for As（V）,which is 2.5 times as large as that of natural hematite adsorbent.The study suggests that MIOs could be potentially used as the adsorbent of As（V） in wastewater.展开更多
A novel ammonium template containing three ammonium sites was synthesized. Two ammoniums located on the linear component served as template for cucurbit[6]uril to form the CB-based pseudo[2]rotacane while another one ...A novel ammonium template containing three ammonium sites was synthesized. Two ammoniums located on the linear component served as template for cucurbit[6]uril to form the CB-based pseudo[2]rotacane while another one located on the macrocyclic component played a role of template for clipping reaction. As a result of a ＇＇threading-followed-by-clipping＇＇ approach, a novel hetero pseudo[2]rota[2]catenane was successfully constructed.展开更多
Three-dimensionally (3D) long range ordered macroporous SiC ceramics were prepared through infiltrating polymethylsilane (PMS) into the 3D ordered sacrificial silica template, pyrolysis and the template removal. It wa...Three-dimensionally (3D) long range ordered macroporous SiC ceramics were prepared through infiltrating polymethylsilane (PMS) into the 3D ordered sacrificial silica template, pyrolysis and the template removal. It was found that the pore size (84―658 nm), BET surface area (299.44―584.64 m2/g) and micropore volume (0.25―0.64 cm3/g) of the achieved porous SiC can be tailored by utilizing different sizes silica sphere templates. There exist three kinds of pores in the porous ceramics: sphere inversed pores, windows and mesopores (2―5 nm). The sphere inversed pores were packed as hcp structure and three dimensionally penetrated through the windows, and the mesopores endowed the porous ceramics surprising high BET surface areas and micropore volumes.展开更多
A capillary-enforced template-based method has been applied to fabricate calcium copper titanate (CaCu3Ti4O12, CCTO) nanotubes (diameter ~200 nm) by filling sol-gel CCTO precursor solution into the nanochannels of por...A capillary-enforced template-based method has been applied to fabricate calcium copper titanate (CaCu3Ti4O12, CCTO) nanotubes (diameter ~200 nm) by filling sol-gel CCTO precursor solution into the nanochannels of porous anodic aluminum oxide (AAO) templates, subsequent heating for phase formation and fi- nally the removal of nano-channel templates by applying basic solution. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) have been employed to characterize the morphology, structure, and composition of as-prepared nanotubes. XRD and selected-area electron diffraction (SAED) in-vestigations demonstrated that postannealed (750○C for 1 h) CCTO nanotubes were poly-crystalline with a cubic pseudo-perovskite cry- stal structure. The FE-SEM and TEM results showed that CCTO nanotubes were of uniform diameter (~200 nm) throughout their length. High resolution TEM (HRTEM) analysis confirm- ed that the obtained CCTO nanotubes are made of randomly aligned nano-particles 5-10 nm in size. EDX analysis demonstrated that stoichi- ometric CaCu3Ti4O12 was formed. The possible formation mechanism of CCTO nanotubes in the AAO template is discussed.展开更多
The effects of glass flit on the sintering and electric properties of PMN-PT textured ceramics were investigated. The glass frits, including PbO, Bi2O3 and ZnO, were selected since liquid phase sintering lowered the P...The effects of glass flit on the sintering and electric properties of PMN-PT textured ceramics were investigated. The glass frits, including PbO, Bi2O3 and ZnO, were selected since liquid phase sintering lowered the PMN-PT sintering temperature. The piezoelectric properties of PMN-PT ceramics with glass frit addition are strongly dependent on the densification. The addition of glass frits into PMN-PT matrix reduced the sintering temperature to 1 100℃ instead of 1 150 ℃ for samples without glass. The piezoelectric coefficients （d33） of PMN-PT textured ceramics achieved 568 pc/N with 1 wt% excess PbO.展开更多
A microporous organically-templated tungsten heteropolyacid, (C2N2H10)2 [H2P2W18O62]?8H2O, with a new type was hydrothermally synthesized by using ethylenediamine as the structure-directing agent. Its structure was ...A microporous organically-templated tungsten heteropolyacid, (C2N2H10)2 [H2P2W18O62]?8H2O, with a new type was hydrothermally synthesized by using ethylenediamine as the structure-directing agent. Its structure was determined by single-crystal X-ray diffraction analysis. Crystal data: monoclinic, space group P21/c, a = 14.633(4), b = 19.432(5), c = 26.776(5) ?, β = 117.849(11)o, V = 6732(3) ?3, Z = 4, Mr = 4615.48, Dc = 4.554 g/cm3, μ(MoKα) = 30.781 mm-1, F(000) = 7976, the final R = 0.0678 and wR = 0.1359. The crystal of the title compound is constructed by Dawson anions and organic dications forming a novel “hollow” channel system.展开更多
In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly p...In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10−4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band.展开更多
5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high in...5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.展开更多
Metal–organic frameworks(MOFs)with redox-active metal sites and controllable crystalline structures make it possible to access the merits of highly-efficient electrode materials in electrochemical energy storage syst...Metal–organic frameworks(MOFs)with redox-active metal sites and controllable crystalline structures make it possible to access the merits of highly-efficient electrode materials in electrochemical energy storage systems.However,most MOFs suffer from low capacitance and poor cycling stability that largely thwart their application.Herein,we present the holey graphene oxide(HGO)template strategy to prepare nano two-dimensional Ni(BDC)with HGO as both template and capping agent(denoted as Ni(BDC)-HGOx,x=10,20,30,and 40 according to the added HGO amount).Structural analyses reveal that HGO can significantly inhibit the Ni(BDC)agglomeration,thus offering a high ion-accessible surface area.Ni(BDC)-HGO30 with well-exposed active sites exhibits a high capacitance of 1,115.6 F·g^(−1) at 1 A·g^(−1) in 6 M KOH aqueous,1.8 times that of bulk Ni(BDC).An asymmetric supercapacitor with Ni(BDC)-HGO30 as a positive electrode and activated carbon as the opposing electrode delivers an energy density of 52.5 W·h·kg^(−1) and a power density up to 18.0 kW·kg−1,with 92.5%capacitance retention after 10,000 cycles.Galvanostatic intermittent titration technique and in situ electrochemical–Raman measurements were exploited to elucidate the electrochemical behavior of Ni(BDC)-HGO30.These results pave the way for the development of rationally tuned MOF materials for enhancing supercapacitor performances.展开更多
基金the support from the CIPHER Project(IIID 2018-008)funded by the Commission on Higher Education-Philippine California Advanced Research Institutes(CHED-PCARI)。
文摘Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts.TMPs have been produced in various morphologies,including hollow and porous nanostructures,which are features deemed desirable for electrocatalytic materials.Templated synthesis routes are often responsible for such morphologies.This paper reviews the latest advances and existing challenges in the synthesis of TMP-based OER and HER catalysts through templated methods.A comprehensive review of the structure-property-performance of TMP-based HER and OER catalysts prepared using different templates is presented.The discussion proceeds according to application,first by HER and further divided among the types of templates used-from hard templates,sacrificial templates,and soft templates to the emerging dynamic hydrogen bubble template.OER catalysts are then reviewed and grouped according to their morphology.Finally,prospective research directions for the synthesis of hollow and porous TMP-based catalysts,such as improvements on both activity and stability of TMPs,design of environmentally benign templates and processes,and analysis of the reaction mechanism through advanced material characterization techniques and theoretical calculations,are suggested.
基金This work was supported by the National Natural Science Foundation of China(Nos.51772309 and 52130207).The authors thank Prof.Jing WANG(Dalian University of Technology)for the synthesis of Al2O3 platelets.
文摘Transparent Al_(2)O_(3) ceramics with grains aligned to the c-axis were prepared by adding platelets with a low aspect ratio into fine equiaxed particles.The mixed powders were formed into green bodies using spontaneous coagulation casting and sintered by pressureless sintering and hot-isostatic pressure sintering.Zeta potentials and rheological behavior of the slurries,relative densities of green bodies,and orientation and optical properties of sintered bodies were investigated and discussed.The platelet with a high aspect ratio suppressed densification more seriously during sintering than the one with a low aspect ratio.An excellent oriented structure was obtained when 5 wt%platelets with a low aspect ratio were added,and transparent Al_(2)O_(3) ceramics with grains aligned to c-axis were successfully prepared;the in-line transmittance was 78.4%at 600 nm,which is the highest one in the currently reported literature.
基金the National Natural Science Foundation of China (Grant No.20073025), Key Teacher Fund and CSC of Ministry of the Education, State Major Basic Research Project of China and Israel Science Foundation.
文摘The organic lyotropic liquid crystal with long-range structural order is used as template to assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hybrid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the first time. The change of template structure after doping and the stability origin of dual-doped system are characterized by small angle X-ray scattering and polarized optical microscopy. Results show that the interaction and space matching between surfactant bilayers and doped particles are key factors to obtain stable hybrid.
文摘Two organically templated uranium phosphites, （C4H12N）（UO2）（HPO3）（NO3） （Mr = 486.16） 1 and （C16H36N）2（UO2）2（H2PO3）2（HPO3）（NO3）2 （Mr= 1390.95） 2, were prepared by evaporation from aqueous solution of uranyl nitrate, phosphite acid and their respective organic ammonium hydroxids. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared and fluorescence spectroscopy. In 1, pentagonal [UO7] bipyramids share comers with three [HPO3]2- tetrahedra and one edge with a [NO3]- anion to form [（UO2）- （HPO3）（NO3）]^- ladder-like chains parallel to the b axis. The structure of 2 is also based upon one-dimensional anionic [（UO2）2（H2PO3）2（HPO3）（NO3）2]2-chains of comer-sharing penta- gonal [UOT] bipyramids with [H2PO3]- and [HPO3] tetrahedra, which is still unknown in structural chemistry of uranium so far. Crystal data for 1： monoclinic, space group C2/m, a = 21.808（7）, b = 6.9605（15）, c = 8.357（2） A, β = 98.327（15）°, V= 1255.2（6） A^3, Z = 4, Dc = 2.573 g/cm^3, F（000） = 888, μ = 13.086 mm^-1 the final R = 0.0418 and wR = 0.0906 （I 〉 2σ（I））; and those for 2： monoclinic, space group C2/c, a = 36.4549（8）, b = 14.5296（11）, c = 20.8253（11） A, β = 101.7440（8）°, V= 10799.7（10） A3, Z = 8, Dc= 1.711 g/cm^3, F（000） = 5424,μ = 6.144 mm^-1, the final R= 0.0368 and wR= 0.0865 （I〉 2σ（I））.
基金supported by the Natural Science Foundation of Ningbo City (2007A610022) K. C. Wong Magna Fund in Ningbo University
文摘Two new nonmetal borates, [（C2H10N2）]2[B14O20（OH）6] 1 and [C8H22N4][B5O6（OH）4]2 2, have been synthesized under mild conditions and characterized by single-crystal X-ray diffraction, FTIR, elemental analysis and thermogravimetric analysis. Crystal data for compound 1： triclinic, space group P^-1, a = 8.4979（17）, b = 8.8498（18）, c = 10.065（2）A^°, α = 95.01（3）, β = 96.99（3）, γ = 116.82（3）°, V= 661.8（3）A^°^3, Z= 1, Mr = 697.63, Dc = 1.751 g/cm^3,μ = 0.163 mm^-1, F（000） = 356, the final R = 0.0372 and wR = 0.0968 （I 〉 2σ（I））; and those for compound 2： monoclinic, space group P21/c, a = 9.1867（18）, b= 14.118（3）, c = 10.334（2）A^°, β = 91.48（3）°, V = 1339.8（5）A^°^3, Z = 2, Mr = 610.46, Dc = 1.513 g/cm^3,μ = 0.135 mm^-1, F（000） = 632, the final R = 0.0350 and wR = 0.0912 （I 〉 2σ（I））. For both 1 and 2, the anionic units are interlinked via O-H…O hydrogen bonds to form a 3D supramolecular network, while the protonated cations are located in the free space of the inorganic borate framework and interact with the anions by electrostatic attraction and extensive N-H…O hydrogen bonds.
基金financial support from the National Natural Science Foundation of China(Nos.52072092 and 51922083)the Natural Science Foundation of Heilongjiang Province(No.YQ2019E026)the Fundamental Research Funds for the Central Universities(No.HIT.OCEF.2021018).
文摘Enhanced piezoelectric response was usually achieved in(Bi_(0.5) Na_(0.5))TiO_(3)(BNT)-based ceramics with sacrifice of depolarization temperature T_(d),seriously limiting their usage range in electromechanical applications.In this work,we propose to explore piezoelectric anisotropy and domain engineering in compositionµstructure-controlled textured ceramics to resolve this issue.[001]c-textured 0.94(Bi_(0.5) Na_(0.5))TiO_(3)–0.06BaTiO_(3)(0.94BNT-0.06BT)ceramics with Lotgering factor F_(001)-91% were fabricated through homoepitaxial templated grain growth(TGG)via using 0.94BNT-0.06BT microplatelet templates.The textured samples exhibited more ordered domains with facilitated domain switching behavior,being consistent with saturated high polarization achieved at lower electric fields.Increasing F_(001) to above 60%enables rapid enhancement of piezoelectric response.Notably,compared to non-textured counterpart,the maximally textured ceramics exhibited-236%enhanced piezoelectric coefficient(d_(33)-302 pC/N)and-280% enhanced piezoelectric voltage coefficient(g_(33)-49.8×10^(−3)Vm/N),together with slightly increased depolarization temperature(T_(d)-106℃).Moreover,those values are approaching or even higher than the single-crystal values.This work not only provides important guidelines for design and synthesis of novel textured ceramics with improved comprehensive electrical properties,but also can expand application fields of BNT-based ceramics.
基金supported by the National Natural Science Foundation of China (No. 22179063)。
文摘Covalent organic frameworks(COFs), as highly tunable porous crystalline materials, have promising applications in potassium-ion batteries(PIBs) due to their abundant charge carrier transport channels and excellent structural stability. However, the excessive stacking of interlayer electron clouds makes it difficult to expose internal active sites. Strategies to design functional COFs with controllable morphology and copious active sites are promising but still challenging. Herein, by utilizing the condensation between1,3,5-triformylbenzene(TFB) and p-phenylenediamine(PPD) and using amino-modified SiO_(2) nanospheres as templates, we synthesize core-shell NH_(2)-SiO_(2)@TP-COF. Through NaOH etching of NH_(2)-SiO_(2)@TP-COF, we obtain imine-based TP-COF hollow nanospheres, which shows excellent potassium storage performance when applied to the anode for PIBs. Ex-situ analysis and density functional theory calculations reveal that C=N groups and benzenes are active sites for K^(+) storage.
文摘Various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrodeposition. These structures occur if the electroplating is continued after the nanowires appear on the membrane surface. By varying the membrane ge- ometry, pulse current electroplating parameters, and alternating electrodeposition from two baths composed of a variety of electrolytes, diverse models were fabricated, including a hollow container with a wall thickness of 10 nm 20 nm. This biomimetic method suggests an analogy between the shape-forming processes of plants and their metallic models. Nanostruc- tured mesostructures of various metals （Ag, Pd, Ni）, alloys （PdNi, Pbln） and hybrid structures .（PdNi/Pb, PdNi/Pbln） were obtained. They can be of interest for fundamental research （self-assembly, morphogenesis） as well as for applications in nanotechnology （catalysis, nanoplasmonics, medicine, superhydrophobic surfaces）.
基金supported by the National High Technology Research and Development Program of China(863 Program)(2012AA053305)the International Cooperation Project from Ministry of Science and Technology of China(2010DFA64080)
文摘In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption characterization technologies. The high-pressure hydrogen uptake performance was analyzed using standard Pressure-Composition-Temperature apparatus in order to study the pore size effects on hydrogen uptake. These as-obtained porous carbons showed different characteristics of pore size distribution as well as specific surface area. The results indicate that the most effective pores for adsorbing hydrogen depended on the storage pressure. These ultramicropores （0.65-0.85 nm） could be the most effective pores on excess H2 uptake at 1 bar, however, micropores （0.85-2 nm） would play a more important role in excess H2 uptake at higher pressure at 77 K. At room temperature, pore size effects on H2 uptake capacity were very weak. Both specific surface area and total pore volume play more important roles than pore size for H2 uptake at room temperature, which was clearly different from that at 77 K. For applications in future, the corncob-derived activated carbons can be more available than zeolite templated carbons at 77 K. Element doping enhanced hydrogen uptake could be main research direction for improving H2 uptake capacity at room temperature.
基金funded through ACORN,an EPSRC/DTi IMPACT-FARADAY partnershipThe support of Procter & Gamble is gratefully acknowledged
文摘Titanium dioxide was deposited from aqueous suspension onto cellulosic surfaces. Titania was sourced from Degussa （P25TM, 70：30 anatase：rutile）. Dry uptake of particles was shown to be rapid and dominant with one-third of the deposition occurring in less than 30 s and over one-half in the first minute. Isotherms were recorded to compare the rate of titanium deposition on dry and pre-wetted cotton. In the dry case uptake reached a maximum in 30 min whereas in the pre-wetted case the uptake was seen to continue beyond 180 min. A broad trend of higher deposition occurring at lower pH was seen, corresponding to the region where surface charges were opposite and thus attractive. Dry pickup was less significant at high pH. The response to varying ionic strength was complex and was attributed to the combined effect of charge screening, particle aggregation and consequent particle entrapment or occlusion. Titania deposition into the interstices of woven cotton sheets resulted in the formation of inorganic, nanoparticulate skeletons which could be isolated by controlled combustion of the cellulose and thus cotton was suggested to have potential for the templated synthesis of high surface area semiconductor materials.
基金This work is supported by the National Natural Science Foundation of China (grant No: 20372056)a Research Fund from the Royal Society of Chemistry. UK.
文摘A novel macrolactonization method was developed using a chiral β-lactam as the template. This novel method features that the macrocyclization is simultaneously achieved while a TBS protected hydroxy group is deprotected.
基金Supported by the National Natural Science Foundation of China(No.51002080)the Research Funds of Nanjing University of Information Science and Technology(NUIST),China(No.S8108179001)+1 种基金the College Students Practice Innovative Projects of Jiangsu Province,China(No.N1885010087)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Mesostructured iron oxides（MIOs） were nanocasted from a plugged hexagonal templated silica（PHTS） with a Brunauer-Emmett-Teller（BET） surface area of 694 m 2 /g.Results of X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N 2 adsorption-desorption suggest that the nanocasted MIOs are synthetic hematite（α-Fe2O3） with a wormhole-like mesoporous network.As（V） adsorption test shows that the selected MIO—MIO-500（calcinated at 500 °C） with a BET surface area of 82 m^ 2 /g has a maximum adsorption capacity of 5.39 mg/g for As（V）,which is 2.5 times as large as that of natural hematite adsorbent.The study suggests that MIOs could be potentially used as the adsorbent of As（V） in wastewater.
基金financial support from National Natural Science Foundation of China (No. 21402057)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Educationthe self-determined research funds of CCNU from the colleges’ basic research and operation of MOE (Nos. CCNU14A05009, CCNU14F01003)
文摘A novel ammonium template containing three ammonium sites was synthesized. Two ammoniums located on the linear component served as template for cucurbit[6]uril to form the CB-based pseudo[2]rotacane while another one located on the macrocyclic component played a role of template for clipping reaction. As a result of a ＇＇threading-followed-by-clipping＇＇ approach, a novel hetero pseudo[2]rota[2]catenane was successfully constructed.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 59972042)the Korea National Research Laboratory Program (Grant No. M10400000061-04J0000-06110) the Doctor Innovation Fund of National University of Defense Technology in China (2001-2004).
文摘Three-dimensionally (3D) long range ordered macroporous SiC ceramics were prepared through infiltrating polymethylsilane (PMS) into the 3D ordered sacrificial silica template, pyrolysis and the template removal. It was found that the pore size (84―658 nm), BET surface area (299.44―584.64 m2/g) and micropore volume (0.25―0.64 cm3/g) of the achieved porous SiC can be tailored by utilizing different sizes silica sphere templates. There exist three kinds of pores in the porous ceramics: sphere inversed pores, windows and mesopores (2―5 nm). The sphere inversed pores were packed as hcp structure and three dimensionally penetrated through the windows, and the mesopores endowed the porous ceramics surprising high BET surface areas and micropore volumes.
文摘A capillary-enforced template-based method has been applied to fabricate calcium copper titanate (CaCu3Ti4O12, CCTO) nanotubes (diameter ~200 nm) by filling sol-gel CCTO precursor solution into the nanochannels of porous anodic aluminum oxide (AAO) templates, subsequent heating for phase formation and fi- nally the removal of nano-channel templates by applying basic solution. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) have been employed to characterize the morphology, structure, and composition of as-prepared nanotubes. XRD and selected-area electron diffraction (SAED) in-vestigations demonstrated that postannealed (750○C for 1 h) CCTO nanotubes were poly-crystalline with a cubic pseudo-perovskite cry- stal structure. The FE-SEM and TEM results showed that CCTO nanotubes were of uniform diameter (~200 nm) throughout their length. High resolution TEM (HRTEM) analysis confirm- ed that the obtained CCTO nanotubes are made of randomly aligned nano-particles 5-10 nm in size. EDX analysis demonstrated that stoichi- ometric CaCu3Ti4O12 was formed. The possible formation mechanism of CCTO nanotubes in the AAO template is discussed.
基金Supported by the National Natural Science Foundation of China (No.50502027)the 973 Project (No. 2002CB613303)
文摘The effects of glass flit on the sintering and electric properties of PMN-PT textured ceramics were investigated. The glass frits, including PbO, Bi2O3 and ZnO, were selected since liquid phase sintering lowered the PMN-PT sintering temperature. The piezoelectric properties of PMN-PT ceramics with glass frit addition are strongly dependent on the densification. The addition of glass frits into PMN-PT matrix reduced the sintering temperature to 1 100℃ instead of 1 150 ℃ for samples without glass. The piezoelectric coefficients （d33） of PMN-PT textured ceramics achieved 568 pc/N with 1 wt% excess PbO.
基金This work was supported by the Fund for Distinguished Young Scholars (Inorganic Chemistry No. 20025101)+1 种基金 Key Project from NNSFC (No.50332050) State "863" Project (No. 2002AA324070) and Fund of Shanghai Optical Science and Technology (No. 022261015)
文摘A microporous organically-templated tungsten heteropolyacid, (C2N2H10)2 [H2P2W18O62]?8H2O, with a new type was hydrothermally synthesized by using ethylenediamine as the structure-directing agent. Its structure was determined by single-crystal X-ray diffraction analysis. Crystal data: monoclinic, space group P21/c, a = 14.633(4), b = 19.432(5), c = 26.776(5) ?, β = 117.849(11)o, V = 6732(3) ?3, Z = 4, Mr = 4615.48, Dc = 4.554 g/cm3, μ(MoKα) = 30.781 mm-1, F(000) = 7976, the final R = 0.0678 and wR = 0.1359. The crystal of the title compound is constructed by Dawson anions and organic dications forming a novel “hollow” channel system.
基金The authors thank Kai Metsäkoivu for the technical assistance and Henrikki Liimatainen for providing us with nanocellulose materialsThe financial support received partly from EU Interreg Nord-Lapin liitto(project Transparent,conducting and flexible films for electrodes),Academy of Finland(6Genesis Flagship under Grant 318927)+1 种基金University of Oulu(projects Entity and PoC:Ultra-low permittivity and loss porous nanocomposites for future 6G telecommunication),Hungarian National Research,Development and Innovation Office through the projects GINOP-2.3.2-15-2016-00013 and GINOP-2.3.3-15-2016-00010the Ministry of Human Capacities,Hungary,grant 20391-3/2018/FEKUSTRAT is acknowledged.D.S.is thankful for the János Bolyai Research Scholarship of the Hungarian Academy of Sciences.
文摘In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10−4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band.
基金financially supported by the National Natural Science Foundation of China(No.21606100)the Natural Science Foundation of Jiangsu Province(No.BK20180850)+1 种基金the China Postdoctoral Science Foundation(Nos.2019M651740 and 2019T120397)the Young Talent Cultivate Programme of Jiangsu University。
文摘5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.
基金supported by the National Natural Science Foundation of China(Nos.22105226 and 51972342)the Shandong Province Postdoctoral Innovative Talent Support Program(No.SDBX20200004)+3 种基金the China Postdoctoral Science Foundation(No.2020M682253)the Qingdao Postdoctoral Funding Project(No.ZX20210067)he Independent innovation scientific research project(No.20CX06100A)the Taishan Scholar Project of Shandong Province(No.ts20190922).
文摘Metal–organic frameworks(MOFs)with redox-active metal sites and controllable crystalline structures make it possible to access the merits of highly-efficient electrode materials in electrochemical energy storage systems.However,most MOFs suffer from low capacitance and poor cycling stability that largely thwart their application.Herein,we present the holey graphene oxide(HGO)template strategy to prepare nano two-dimensional Ni(BDC)with HGO as both template and capping agent(denoted as Ni(BDC)-HGOx,x=10,20,30,and 40 according to the added HGO amount).Structural analyses reveal that HGO can significantly inhibit the Ni(BDC)agglomeration,thus offering a high ion-accessible surface area.Ni(BDC)-HGO30 with well-exposed active sites exhibits a high capacitance of 1,115.6 F·g^(−1) at 1 A·g^(−1) in 6 M KOH aqueous,1.8 times that of bulk Ni(BDC).An asymmetric supercapacitor with Ni(BDC)-HGO30 as a positive electrode and activated carbon as the opposing electrode delivers an energy density of 52.5 W·h·kg^(−1) and a power density up to 18.0 kW·kg−1,with 92.5%capacitance retention after 10,000 cycles.Galvanostatic intermittent titration technique and in situ electrochemical–Raman measurements were exploited to elucidate the electrochemical behavior of Ni(BDC)-HGO30.These results pave the way for the development of rationally tuned MOF materials for enhancing supercapacitor performances.
