A new flexible double betaine L （L = 1,4-bis（pyridinio-4-carboxylato-N-methyl）benzene, C20H16N2O4） and its cadmium（Ⅱ） complex [Cd（H2O）aL（NO3）]NO3.H2O 1 were synthesized. Complex 1 was obtained by self-assem...A new flexible double betaine L （L = 1,4-bis（pyridinio-4-carboxylato-N-methyl）benzene, C20H16N2O4） and its cadmium（Ⅱ） complex [Cd（H2O）aL（NO3）]NO3.H2O 1 were synthesized. Complex 1 was obtained by self-assembly reaction of [Cd（NO3）2]-4H2O and L in hot water,and its crystal structure was determined by single-crystal X-ray diffraction analysis. Crystallographic data for complex 1： C20H24CdN4O14.H2O, Mr = 674.85, monoclinic, space group P21/c, a =13.7854（3）, b = 14.2820（3）, c = 14.9188（4） ,A°, β = 116.418（1）°, V = 2630.5（1）A°^3, Z = 4, Dc= 1.704g/cm^3,/J（MoKα） = 0.911 mm^-1, F（000） = 1368, the final R = 0.0315 and wR = 0.0768 for 3637 observed reflections with I 〉 2σ（I）. In complex 1, L acts as a monodentate ligand to link a Cd（Ⅱ） ion in a novel coordination mode of double betaines. The mononuclear [Cd（H2O）aL（NO3）] units are connected through intermolecular hydrogen bonds and π-π stacking reactions to generate a 3D network.展开更多
Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stabl...Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stable and high capacity cathode materials due to their complicated reaction mechanism and slow Zn-ion transport kinetics.This study reports a unique 3 D ’flower-like’ zinc cobaltite(ZnCo_(2)O_(4-x)) with enriched oxygen vacancies as a new cathode material for aqueous ZIBs.Computational calculations reveal that the presence of oxygen vacancies significantly enhances the electronic conductivity and accelerates Zn^(2+) diffusion by providing enlarged channels.The as-fabricated batteries present an impressive specific capacity of 148.3 mAh g^(-1) at the current density of 0.05 A g^(-1),high energy(2.8 Wh kg^(-1)) and power densities(27.2 W kg^(-1)) based on the whole device,which outperform most of the reported aqueous ZIBs.Moreover,a flexible solid-state pouch cell was demonstrated,which delivers an extremely stable capacity under bending states.This work demonstrates that the performance of Zn-ion storage can be effectively enhanced by tailoring the atomic structure of cathode materials,guiding the development of low-cost and eco-friendly energy storage materials.展开更多
Understanding the unique characteristics of continuous-flow photochemistry will lead to a paradigm shift in the way we enhance sustainability and wellbeing.In this mini-review,we first provide a succinct overview of w...Understanding the unique characteristics of continuous-flow photochemistry will lead to a paradigm shift in the way we enhance sustainability and wellbeing.In this mini-review,we first provide a succinct overview of working principles of this technique and discuss several recent synthetic protocols.Then,emphasis is given to those representative examples which address environmental issues such as indoor air pollutants and water contamination.Finally,recent progress made using this technique to deal with rising CO2 emission,solar energy utilization and biomedical equipment is described.It is believed that this mini-review could inspire more chemists to utilize this technique in their research,either in the academic or industrial field.展开更多
A novel Zr-substituted polyoxometalate（POM） H2K3[Na6（H2O）9][Zr3Na3O3（H2O）3-（GeW9O（34））2]·12H2O（1） has been made under hydrothermal conditions. 1 was characterized by infrared spectrum, thermogravimetr...A novel Zr-substituted polyoxometalate（POM） H2K3[Na6（H2O）9][Zr3Na3O3（H2O）3-（GeW9O（34））2]·12H2O（1） has been made under hydrothermal conditions. 1 was characterized by infrared spectrum, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Crystal data are： H（50）O（95）Na9K3Ge2Zr3W（1）8, hexagonal space group P63/mmc, a = 15.2251（6）, b = 15.2251（6）, c = 25.035（2） , V = 5025.7（6） 3, Z = 2, Dc = 3.716 mg/m3, μ = 21.648 mm（-1）, F（000） = 4726, the final R = 0.0259 and w R = 0.0647 for 1487 observed reflections with I 2σ（I）. Single-crystal X-ray structure analysis reveals that 1 exhibits a 3-dimensional framework structure based on Zr3Na3-substituted polyanions [Zr3Na3O3（H2O）3（GeW9O（34））2]（11-） and [Na6（H2O）9]（6＋） clusters building blocks. UV-Vis spectrum indicates that 1 is a wide-gap semiconductor. In addition, the proton-conducting property of 1 was also investigated.展开更多
The crystal structure of the title compound [Mn(sapn)(H2O)2]Br (H2sapn = N,N?bis-(salicylidene)-1,3-diaminopropane) with formula C17H18N2O4MnBr and Mr = 449.18 has been determined by X-ray diffraction. The crystal is ...The crystal structure of the title compound [Mn(sapn)(H2O)2]Br (H2sapn = N,N?bis-(salicylidene)-1,3-diaminopropane) with formula C17H18N2O4MnBr and Mr = 449.18 has been determined by X-ray diffraction. The crystal is triclinic with space group P , a = 7.777(1), b = 10.459(2), c = 11.96(3), = 78.22(1), =75.16(8), = 86.80(5)? V = 919(3)3, Dc = 1.631g/cm3, F(000) = 456, = 2.917 cm-1 and Z = 2, with R = 0.0428 and wR = 0.1092 for 2427 reflections (I > 2s(I)). Two nitrogen and two oxygen atoms from the sapn group chelate to the MnⅢ ion, forming a distorted octahedral geometry together with two coordinated water molecules. A bromide anion exists outside as a counter ion.展开更多
Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR,...Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR, TGA and single-crystal X-ray structural analyses. The results of X-ray crystallography analyses exhibit that 1 consists of one a-Keggin anion [a-H5PW11CoO40]2- and one isolated [Co（2,2＇-bipy）3]2＋ complex, while 2 is constructed from one a-Keggin anion [a- HBW12O40]4- and two isolated [Fe（2,2＇-bipy）3]2＋ cations. The data for 1： orthorhombic system, space group Pbcn, a = 16.062（6）, b = 27.278（10）, c = 16.951（6）A, V = 7427（5）A3 and Z = 4; and those for 2： triclinic system, space group P1, a = 13.787（3）, b = 17.857（5）, c = 18.918（5）A, a = 88.009（12）, β = 72.768（10）, γ = 74.935（10）°, V = 4291（2）A3 and Z = 2.展开更多
The title compound (H3NCH2CH2NH3)4[(VO)6(B10O22)2]·(H3O)7 1 has been synthe- sized by the hydrothermal method and determined by X-ray crystallography. Crystallographic data: monoclinic, space group C2/c, a = 20.2...The title compound (H3NCH2CH2NH3)4[(VO)6(B10O22)2]·(H3O)7 1 has been synthe- sized by the hydrothermal method and determined by X-ray crystallography. Crystallographic data: monoclinic, space group C2/c, a = 20.250(4), b = 13.448(3), c = 21.655(4) ?, β = 97.05(3)°, Mr = 851.74 (C4H30.5B10N4O28.5V3), V = 5852(2) ?3, Z = 8, Dc = 1.933 g/cm3, μ = 1.057 mm-1, F(000) = 3436, R = 0.0500 and wR = 0.1442 for 4511 observed reflections with I > 2σ(I). The structure con- sists of [(VO)6(B10O22)2]15- cluster anions that have a central band of six trans-edge-sharing VO5 square pyramids capped by two [B10O22]14- polyborate ligands. Other characterizations are also describ- ed by elemental analysis, IR spectrum and thermal analysis.展开更多
Phospho-olivine LiFePO4 has been prepared using a facile hydrothermal method by optimizing the reaction temperatures. Structural and morphological properties of the as-prepared LiFePO4 powders are systematically chara...Phospho-olivine LiFePO4 has been prepared using a facile hydrothermal method by optimizing the reaction temperatures. Structural and morphological properties of the as-prepared LiFePO4 powders are systematically characterized using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, infrared spectra, UV-vis spectra, and Mossbauer spectroscopy. It is demonstrated that the samples prepared in the temperature range from 160 to 200℃ crystallize in a single phase of phospho-olivine structure. All particles are rod-like, showing dimensions of approximately 150-200 nm in width and 500-600 nm in length with a preferential growth direction of [001]. Within the lattice of LiFePO4 rods, Fe2＋ ions partially disorderly occupy the Li＋ sites, which increases the cell volume. The electrochemical performance of LiFePO4 is investigated by charge/discharge experiments. It is found that LiFePO4 rods prepared at 200℃ deliver a specific discharge capacity of 147 mAh g-1, which is apparently superior to those prepared at lower reaction temperatures like 160 and 180 ℃This observation is explained in terms of the thinner surface noncrystalline layer and lower level of Fe2＋ disorderly occupying the Li＋ sites.展开更多
Two new compounds Cu(pic)2[CO(NH2)2]2 1 and (picH2)2[Cu(pic)2(SCN)2] 2 were prepared from the reaction of picolinic acid and copper(II) per-chlorate by using carbamide to adjust pH = 4 in the preparation of compound 1...Two new compounds Cu(pic)2[CO(NH2)2]2 1 and (picH2)2[Cu(pic)2(SCN)2] 2 were prepared from the reaction of picolinic acid and copper(II) per-chlorate by using carbamide to adjust pH = 4 in the preparation of compound 1 and KSCN to adjust pH = 6 in the preparation of 2. Crystal data for 1: monoclinic system, space group P21/n with a = 7.441(1), b = 14.291(2), c = 7.790(1) ? b = 95.855(2), V = 824.0(2) ?, Dc = 1.724 g/cm3, F(000) = 438, C14H16N6O6Cu, Mr = 427.87, m(MoKa) = 1.375 mm-1, Z = 2 and the final R = 0.0365 for 1164 observed reflections. Crystal data for 2: monoclinic system, space group P21/c with a = 9.8237(3), b = 10.0409(3), c = 14.5867(2) ? b = 104.190(2), V = 1394.91(6) ?, Dc = 1.595 g/cm3, F(000) = 686, C26H20N6O8S2Cu, Mr = 672.14, m(MoKa) = 0.994 mm-1, Z = 2 and the final R = 0.0442 for 1651 observed reflections. The Cu(II) atom in both 1 and 2 has a 4+2 elongated octahedral environment with the pic ligands locating on the equatorial plane, and carbamide and SCN occupying the axial sites, respectively. In compound 2, there also exist two protonated picolinate cations for charge balance.展开更多
ABSTRACT A new lanthanumm-ironm complex [La（DMSO）5（H2O）]（μ-CN）2[Fe（CN）4]·H2O 1 （DMSO = dimethylsulfoxide） has been prepared by a facile approach, ball-milling method, and characterized by X-ray diffrac...ABSTRACT A new lanthanumm-ironm complex [La（DMSO）5（H2O）]（μ-CN）2[Fe（CN）4]·H2O 1 （DMSO = dimethylsulfoxide） has been prepared by a facile approach, ball-milling method, and characterized by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 9.7125（3）, b = 21.5336（7）, c = 14.3804（5）A, β = 93.242（3）°, C16H34FeLaN60O7S5, Mr= 777.55, V = 3002.8（2）A^3, Z = 4, Dc = 1.720 g/cm^3, S = 1.053, μ（MoKα） = 2.278 mm^-1, F（000） = 1564, R = 0.0490 and ωR = 0.1270. The crystal structure analysis of 1 reveals a slightly distorted squareantiprism eighffold-coordinated La（Ⅲ） ion and a 1-D zigzag chain structure extending through the Fe-CN-La-NC-Fe linkages. The [La（DMSO）5（H2O）]（μ-CN）2[Fe（CN）4] species are held together via hydrogen bonds to form a three-dimensional framework.展开更多
The electronic and structural properties of ReO5 and ReO5 clusters are investigated using density functional theory （DFT） calculations. The lowest energy structures for both the anionic and neutral clusters are dete...The electronic and structural properties of ReO5 and ReO5 clusters are investigated using density functional theory （DFT） calculations. The lowest energy structures for both the anionic and neutral clusters are determined, and the corresponding photoelectron spectrum is simulated. Our results show that ReO5 can be described as an unusual peroxo molecule, Re（O）3（η2-O2） , while ReO5 is found to be exhibiting the O2 o radical character. Molecular orbital analyses and spin density analyses are performed to elucidate the chemical bonding and the electronic and structural properties in these two rhenium oxide clusters.展开更多
The title compound [Cu(dafone)2(DMF)2]?2ClO4 1 (dafone = 4,5-diazafluoren- 9-one, dmf = N,N?-dimethyl formamide) was synthesized by the reaction of Cu(ClO4 )2 and dafone in DMF solution at room temperature with pH = 3...The title compound [Cu(dafone)2(DMF)2]?2ClO4 1 (dafone = 4,5-diazafluoren- 9-one, dmf = N,N?-dimethyl formamide) was synthesized by the reaction of Cu(ClO4 )2 and dafone in DMF solution at room temperature with pH = 3.0. The single-crystal X-ray analysis has revealed that 1 crystallizes in monoclinic, space group P21/n with a = 8.4853(8), b = 13.1520 (14), c = 14.3866(12) ?, β = 102.629(3)o, V = 1566.7(3) ?3, C28H26Cl2CuN6O12, Mr = 773.00, Z = 2, Dc = 1.639 g/cm3 , F(000) = 790, μ = 0.942 mm-1, the final R = 0.0438 and wR = 0.1214 for 3165 obser- ved reflections with I > 2σ(I). X-ray analysis shows that compound 1 has unsymmetric chelation of dafone with one Cu–N bond being much longer than the other. Coordination geometry of Cu is a highly distorted octahedron and the whole structure is stabilized by π-π stacking and static attractive forces from [ClO4]- anions. Based on the crystal data, quantum chemistry calculation at the DFT/ B3LPY level was used to reveal the electronic structure of 1.展开更多
Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivativ...Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivatives, [N（CH3）4]2Na3（NH4）2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·-13H2O（1）, [NH4]7[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·7H2O（2）, [HN（CH2CH2）3NH][（PO4）Mo^V3Mo^VI9O36（V^IVO）2]·-3[N（CH2CH2）3N]·（en）·4.5H2O（3） and [HNH2OH][NH4]2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）4]·24H2O（4）. Single-crystal X-ray diffraction analysis revealed that the anions in 1-3 are two-capped Keggin derivatives with characteristic trans vanadium-oxygen caps, whereas the heteropoly anion in 4 is a tetra-capped α-Keggin derivative with characteristic vanadium-oxygen caps on the equatorial plane.展开更多
A hydrothermal reaction of 1,3,5-benzene-tricarboxylic acid (H3BTC) with cad- mium acetate, zinc acetate and pyridine led to the formation of pink crystals of [Cd2Zn(BTC)2- (H2O)4]n?2nH2O 1. Single-crystal X-ray dif...A hydrothermal reaction of 1,3,5-benzene-tricarboxylic acid (H3BTC) with cad- mium acetate, zinc acetate and pyridine led to the formation of pink crystals of [Cd2Zn(BTC)2- (H2O)4]n?2nH2O 1. Single-crystal X-ray diffraction analysis has revealed that 1 (Cd2ZnC18H18O18) crystallizes in the monoclinic system, space group C2/c with a = 19.4328(7), b = 7.1420(3), c = 18.0426(5) ?, β = 118.035(1)o, V = 2210.3(1) ?3, Mr = 812.49, Dc = 2.442 g/cm3, Z = 4, μ(MoKα) = 3.081 mm-1 and F(000) =1584. A total of 10735 reflections were collected, of which 2544 were unique. The structure was refined to R = 0.0200 and wR = 0.0603 for 2388 observed reflections with I>2σ(I). The crystal structure consists of cadmium(II)/zinc(II) carboxylates of BTC as well as coordination and discrete water molecules. Extension of the coordination geometry around three metal centers (Cd(1), Cd(2) and Zn(1)), two BTC3- ligands and four coordinated water molecules generates a three-dimensional coordination polymer.展开更多
The reduced SnO2（110） surface has been investigated by using first-principles method with a slab model. By examining the vacancy formation energy of three kinds of reduced SnO2（110） surfaces, the most energeticall...The reduced SnO2（110） surface has been investigated by using first-principles method with a slab model. By examining the vacancy formation energy of three kinds of reduced SnO2（110） surfaces, the most energetically favorable defect surface is confirmed to be the surface with the coexistence of bridging and in-plane oxygen vacancies, which is different with the traditional model by only removing bridging oxygen. The results of band structure calculations indicate that the electronic structure of this defect surface is similar to the SnO surface.展开更多
Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal cond...Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu（II） ions linked by three 3-（2-pyridyl）pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-（2-pyridyl）pyrazole ligands.Crystal data of 1：C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850（2）,b = 18.510（4）,c = 17.230（3） ,β = 100.57（3）°,V = 3401.6（12） 3,Z = 4,Dc = 2.324 g/cm3,F（000） = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775（Ⅰ 〉 2σ（Ⅰ））;Crystal data for 2：C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799（2）,b = 14.7970（13）,c = 23.141（2） ,β = 91.6180（10）°,V = 7119.0（11） 3,Z = 4,Dc = 2.077 g/cm3,F（000） = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696（Ⅰ〉 2σ（Ⅰ））.展开更多
A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in...A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in the triclinic.,space group P1 with ceIl parameters:a=O.90363(2)nm,b=1.25078(3)nm,c=1.41303(1)nm,穋m^(-3),Z=2,Mr=756.72,F(000)=760,Ⅲ)and the approxi-mately oriented octahedrally sixfold-coordinated Fe(Ⅲ)are linked by a cyano-bridge group to construct a dinuclear compound.The{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](Ⅲ)-Fe(Ⅲ)interaction is antiferromagnetic.CCDC:223430.展开更多
Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast pho...Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast photogenerated electron-hole recombination.To tackle these issues,herein,we propose a new strategy to modify Cd_(x) Zn_(1-x) S nanoreactors by the simultaneous utilization of ionic-liquid-assisted morphology engineering and MXene-incorporating method.That is,we designed and synthesized a novel hierarchi-cal Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction composite through the in-situ deposition of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets on unique IL-modified Ti_(3) C_(2) MXenes by a one-pot solvothermal method for efficiently PHE.The unique construction strategy tailors the thickness of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets and prevents them from stacking and agglomeration,and especially,optimizes their charge transfer pathways during the photocatalytic process.Compared with pristine Cd_(0.8) Zn_(0.2) S nanosheets,Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) has abun-dant photogenerated electrons available on the Ti_(3) C_(2) surface for proton reduction reaction,owing to the absence of deep-trapped electrons,suppression of electron-hole recombination in Cd_(0.8) Zn_(0.2) S and high-efficiency charge separation at the Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction interface.Moreover,the hy-drophilicity,electrical conductivity,visible-light absorption capacity,and surficial hydrogen desorption of Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) heterostructure are significantly improved.As a result,the heterostructure exhibits out-standing photocatalytic stability and super high apparent quantum efficiency,being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts.This work illustrates the mechanisms of mor-phology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.展开更多
The pore structure and pseudo-graphitic phase(domain size and content)of a hard carbon anode play key roles in improving the plateau capacity of sodium-ion batteries(SIBs),while it is hard to regulate them effectively...The pore structure and pseudo-graphitic phase(domain size and content)of a hard carbon anode play key roles in improving the plateau capacity of sodium-ion batteries(SIBs),while it is hard to regulate them effectively and simultaneously.This study delves into the synthesis of hard carbons with tailored microstructures from esterified sodium carboxymethyl cellulose(CMC-Na).The hard carbon(EHC-500)with maximized pseudo-graphitic content(73%)and abundant uniformly dispersed closed pores was fabricated,which provides sufficient active sites for sodium ion intercalation and pore filling.Furthermore,minimized lateral width(L_(a))of pseudo-graphitic domains in EHC-500 is simultaneously realized to improve the accessibility of sodium ions to the intercalation sites and filling sites.Therefore,the optimized microstructure of EHC-500 contributes to a remarkable reversible capacity of 340 mAh/g with a high plateau capacity of 236.7 mAh/g(below 0.08 V).These findings underscore the pivotal role of microcrystalline structure and pore structure in the electrochemical performance of hard carbons and provide a novel route to guide the design of hard carbons with optimal microstructures towards enhanced sodium storage performance.展开更多
Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, th...Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, their application is hindered by poor cycling stability, resulting from severe volume changes during cycling and slow reaction kinetics due to their complex crystal structure. Here, an efficient and straightforward strategy was employed to in-situ encapsulate single-phase porous nanocubic MnS_(0.5)Se_(0.5) into carbon nanofibers using electrospinning and the hard template method, thus forming a necklace-like porous MnS_(0.5)Se_(0.5)-carbon nanofiber composite(MnS_(0.5)Se_(0.5)@N-CNF). The introduction of Se significantly impacts both the composition and microstructure of MnS_(0.5)Se_(0.5), including lattice distortion that generates additional defects, optimization of chemical bonds, and a nano-spatially confined design. In situ/ex-situ characterization and density functional theory calculations verified that this MnS_(0.5)Se_(0.5)@N-CNF allevi- ates the volume expansion and facilitates the transfer of Na+/electron. As expected, MnS_(0.5)Se_(0.5)@N-CNF anode demonstrates excellent sodium storage performance, characterized by high initial Coulombic efficiency(90.8%), high-rate capability(370.5 m Ahg^(-1) at 10 Ag^(-1)) and long durability(over 5000 cycles at 5 Ag^(-1)). The MnS_(0.5)Se_(0.5)@N-CNF//NVP@C full cell, assembled with MnS_(0.5)Se_(0.5)@N-CNF as anode and Na_(3)V_(2)(PO_4)_(3)@C as cathode, exhibits a high energy density of 254 Wh kg^(-1) can be provided. This work presents a novel strategy to optimize the design of anode materials through structural engineering and Se substitution, while also elucidating the underlying reaction mechanisms.展开更多
基金This work was supported by the NSF for Distinguished Young Scientist of China (20425104) and the NSF of Fujian Province (2005I017, A0420002)
文摘A new flexible double betaine L （L = 1,4-bis（pyridinio-4-carboxylato-N-methyl）benzene, C20H16N2O4） and its cadmium（Ⅱ） complex [Cd（H2O）aL（NO3）]NO3.H2O 1 were synthesized. Complex 1 was obtained by self-assembly reaction of [Cd（NO3）2]-4H2O and L in hot water,and its crystal structure was determined by single-crystal X-ray diffraction analysis. Crystallographic data for complex 1： C20H24CdN4O14.H2O, Mr = 674.85, monoclinic, space group P21/c, a =13.7854（3）, b = 14.2820（3）, c = 14.9188（4） ,A°, β = 116.418（1）°, V = 2630.5（1）A°^3, Z = 4, Dc= 1.704g/cm^3,/J（MoKα） = 0.911 mm^-1, F（000） = 1368, the final R = 0.0315 and wR = 0.0768 for 3637 observed reflections with I 〉 2σ（I）. In complex 1, L acts as a monodentate ligand to link a Cd（Ⅱ） ion in a novel coordination mode of double betaines. The mononuclear [Cd（H2O）aL（NO3）] units are connected through intermolecular hydrogen bonds and π-π stacking reactions to generate a 3D network.
基金supported by the National Natural Science Foundation of China(Nos.51873198,51503184 and 21703248)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB20000000)+1 种基金the Engineering and Physical Sciences Research Council(EPSRC,EP/R023581/1)the RSC Mobility Grant(M19-7656)and the STFC Batteries Network(ST/R006873/1)。
文摘Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stable and high capacity cathode materials due to their complicated reaction mechanism and slow Zn-ion transport kinetics.This study reports a unique 3 D ’flower-like’ zinc cobaltite(ZnCo_(2)O_(4-x)) with enriched oxygen vacancies as a new cathode material for aqueous ZIBs.Computational calculations reveal that the presence of oxygen vacancies significantly enhances the electronic conductivity and accelerates Zn^(2+) diffusion by providing enlarged channels.The as-fabricated batteries present an impressive specific capacity of 148.3 mAh g^(-1) at the current density of 0.05 A g^(-1),high energy(2.8 Wh kg^(-1)) and power densities(27.2 W kg^(-1)) based on the whole device,which outperform most of the reported aqueous ZIBs.Moreover,a flexible solid-state pouch cell was demonstrated,which delivers an extremely stable capacity under bending states.This work demonstrates that the performance of Zn-ion storage can be effectively enhanced by tailoring the atomic structure of cathode materials,guiding the development of low-cost and eco-friendly energy storage materials.
基金Financial support from the National Natural Science Foundation of China(No.21771088)Zhejiang Provincial Natural Science Foundation of China(No.LY20B010005)the open research funds of JLU(2020-9)&FJIRSM,CAS(No.20170034)。
文摘Understanding the unique characteristics of continuous-flow photochemistry will lead to a paradigm shift in the way we enhance sustainability and wellbeing.In this mini-review,we first provide a succinct overview of working principles of this technique and discuss several recent synthetic protocols.Then,emphasis is given to those representative examples which address environmental issues such as indoor air pollutants and water contamination.Finally,recent progress made using this technique to deal with rising CO2 emission,solar energy utilization and biomedical equipment is described.It is believed that this mini-review could inspire more chemists to utilize this technique in their research,either in the academic or industrial field.
基金supported by the National Natural Science Foundation of China(No.21401195)the Natural Science Foundation for young scholars of Fujian province(2015J05041)the open foundation of State Key Laboratory of Structural Chemistry(20160020)
文摘A novel Zr-substituted polyoxometalate（POM） H2K3[Na6（H2O）9][Zr3Na3O3（H2O）3-（GeW9O（34））2]·12H2O（1） has been made under hydrothermal conditions. 1 was characterized by infrared spectrum, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Crystal data are： H（50）O（95）Na9K3Ge2Zr3W（1）8, hexagonal space group P63/mmc, a = 15.2251（6）, b = 15.2251（6）, c = 25.035（2） , V = 5025.7（6） 3, Z = 2, Dc = 3.716 mg/m3, μ = 21.648 mm（-1）, F（000） = 4726, the final R = 0.0259 and w R = 0.0647 for 1487 observed reflections with I 2σ（I）. Single-crystal X-ray structure analysis reveals that 1 exhibits a 3-dimensional framework structure based on Zr3Na3-substituted polyanions [Zr3Na3O3（H2O）3（GeW9O（34））2]（11-） and [Na6（H2O）9]（6＋） clusters building blocks. UV-Vis spectrum indicates that 1 is a wide-gap semiconductor. In addition, the proton-conducting property of 1 was also investigated.
基金This work was supported by The State Key Basic Research and Development Plan (G1998010100) NNSFC (No. 2973309029973047 and 39970177)
文摘The crystal structure of the title compound [Mn(sapn)(H2O)2]Br (H2sapn = N,N?bis-(salicylidene)-1,3-diaminopropane) with formula C17H18N2O4MnBr and Mr = 449.18 has been determined by X-ray diffraction. The crystal is triclinic with space group P , a = 7.777(1), b = 10.459(2), c = 11.96(3), = 78.22(1), =75.16(8), = 86.80(5)? V = 919(3)3, Dc = 1.631g/cm3, F(000) = 456, = 2.917 cm-1 and Z = 2, with R = 0.0428 and wR = 0.1092 for 2427 reflections (I > 2s(I)). Two nitrogen and two oxygen atoms from the sapn group chelate to the MnⅢ ion, forming a distorted octahedral geometry together with two coordinated water molecules. A bromide anion exists outside as a counter ion.
基金Supported by the National Natural Science Fund for Distinguished Young Scholars of China (No. 20725101)the NNSFC (Nos. 50872133 and 20821061)+2 种基金the 973 Program (No. 2006CB932904)the NSF of Fujian Province (No. E0510030)the Knowledge Innovation Program of CAS
文摘Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR, TGA and single-crystal X-ray structural analyses. The results of X-ray crystallography analyses exhibit that 1 consists of one a-Keggin anion [a-H5PW11CoO40]2- and one isolated [Co（2,2＇-bipy）3]2＋ complex, while 2 is constructed from one a-Keggin anion [a- HBW12O40]4- and two isolated [Fe（2,2＇-bipy）3]2＋ cations. The data for 1： orthorhombic system, space group Pbcn, a = 16.062（6）, b = 27.278（10）, c = 16.951（6）A, V = 7427（5）A3 and Z = 4; and those for 2： triclinic system, space group P1, a = 13.787（3）, b = 17.857（5）, c = 18.918（5）A, a = 88.009（12）, β = 72.768（10）, γ = 74.935（10）°, V = 4291（2）A3 and Z = 2.
基金This work was supported by the Natural Science Foundation of Fujian Province (E0110013 and K02028)
文摘The title compound (H3NCH2CH2NH3)4[(VO)6(B10O22)2]·(H3O)7 1 has been synthe- sized by the hydrothermal method and determined by X-ray crystallography. Crystallographic data: monoclinic, space group C2/c, a = 20.250(4), b = 13.448(3), c = 21.655(4) ?, β = 97.05(3)°, Mr = 851.74 (C4H30.5B10N4O28.5V3), V = 5852(2) ?3, Z = 8, Dc = 1.933 g/cm3, μ = 1.057 mm-1, F(000) = 3436, R = 0.0500 and wR = 0.1442 for 4511 observed reflections with I > 2σ(I). The structure con- sists of [(VO)6(B10O22)2]15- cluster anions that have a central band of six trans-edge-sharing VO5 square pyramids capped by two [B10O22]14- polyborate ligands. Other characterizations are also describ- ed by elemental analysis, IR spectrum and thermal analysis.
基金supported by NSFC (No.20831004)National Basic Research Program of China (2011CB935904)+1 种基金FIPYT (No.2009HZ0004-1,2008F3116)FJIRSM fund (Nos.SZD-09002-3,2010KL002)
文摘Phospho-olivine LiFePO4 has been prepared using a facile hydrothermal method by optimizing the reaction temperatures. Structural and morphological properties of the as-prepared LiFePO4 powders are systematically characterized using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, infrared spectra, UV-vis spectra, and Mossbauer spectroscopy. It is demonstrated that the samples prepared in the temperature range from 160 to 200℃ crystallize in a single phase of phospho-olivine structure. All particles are rod-like, showing dimensions of approximately 150-200 nm in width and 500-600 nm in length with a preferential growth direction of [001]. Within the lattice of LiFePO4 rods, Fe2＋ ions partially disorderly occupy the Li＋ sites, which increases the cell volume. The electrochemical performance of LiFePO4 is investigated by charge/discharge experiments. It is found that LiFePO4 rods prepared at 200℃ deliver a specific discharge capacity of 147 mAh g-1, which is apparently superior to those prepared at lower reaction temperatures like 160 and 180 ℃This observation is explained in terms of the thinner surface noncrystalline layer and lower level of Fe2＋ disorderly occupying the Li＋ sites.
基金This work was supported by the National Natural Science Foundation of China (20001007 20131020) Natural Science Foundation of the Chinese Academy of Sciences (KJCX2-H3) and Fujian province (2000F006)
文摘Two new compounds Cu(pic)2[CO(NH2)2]2 1 and (picH2)2[Cu(pic)2(SCN)2] 2 were prepared from the reaction of picolinic acid and copper(II) per-chlorate by using carbamide to adjust pH = 4 in the preparation of compound 1 and KSCN to adjust pH = 6 in the preparation of 2. Crystal data for 1: monoclinic system, space group P21/n with a = 7.441(1), b = 14.291(2), c = 7.790(1) ? b = 95.855(2), V = 824.0(2) ?, Dc = 1.724 g/cm3, F(000) = 438, C14H16N6O6Cu, Mr = 427.87, m(MoKa) = 1.375 mm-1, Z = 2 and the final R = 0.0365 for 1164 observed reflections. Crystal data for 2: monoclinic system, space group P21/c with a = 9.8237(3), b = 10.0409(3), c = 14.5867(2) ? b = 104.190(2), V = 1394.91(6) ?, Dc = 1.595 g/cm3, F(000) = 686, C26H20N6O8S2Cu, Mr = 672.14, m(MoKa) = 0.994 mm-1, Z = 2 and the final R = 0.0442 for 1651 observed reflections. The Cu(II) atom in both 1 and 2 has a 4+2 elongated octahedral environment with the pic ligands locating on the equatorial plane, and carbamide and SCN occupying the axial sites, respectively. In compound 2, there also exist two protonated picolinate cations for charge balance.
基金the NNSFC (20571075, 20521101)the NSF for Distinguished Young Scientist of China (20425104)the NSF of Fujian Province (E0510028)
文摘ABSTRACT A new lanthanumm-ironm complex [La（DMSO）5（H2O）]（μ-CN）2[Fe（CN）4]·H2O 1 （DMSO = dimethylsulfoxide） has been prepared by a facile approach, ball-milling method, and characterized by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 9.7125（3）, b = 21.5336（7）, c = 14.3804（5）A, β = 93.242（3）°, C16H34FeLaN60O7S5, Mr= 777.55, V = 3002.8（2）A^3, Z = 4, Dc = 1.720 g/cm^3, S = 1.053, μ（MoKα） = 2.278 mm^-1, F（000） = 1564, R = 0.0490 and ωR = 0.1270. The crystal structure analysis of 1 reveals a slightly distorted squareantiprism eighffold-coordinated La（Ⅲ） ion and a 1-D zigzag chain structure extending through the Fe-CN-La-NC-Fe linkages. The [La（DMSO）5（H2O）]（μ-CN）2[Fe（CN）4] species are held together via hydrogen bonds to form a three-dimensional framework.
基金the National Natural Science Foundation of China (21071031,21073035 and 90922022)the Natural Science Foundation of Fujian Province (No.2008J0151)
文摘The electronic and structural properties of ReO5 and ReO5 clusters are investigated using density functional theory （DFT） calculations. The lowest energy structures for both the anionic and neutral clusters are determined, and the corresponding photoelectron spectrum is simulated. Our results show that ReO5 can be described as an unusual peroxo molecule, Re（O）3（η2-O2） , while ReO5 is found to be exhibiting the O2 o radical character. Molecular orbital analyses and spin density analyses are performed to elucidate the chemical bonding and the electronic and structural properties in these two rhenium oxide clusters.
基金This work was supported by the Foundation of Education Committee of Fujian Province (JB04016, JB04017)
文摘The title compound [Cu(dafone)2(DMF)2]?2ClO4 1 (dafone = 4,5-diazafluoren- 9-one, dmf = N,N?-dimethyl formamide) was synthesized by the reaction of Cu(ClO4 )2 and dafone in DMF solution at room temperature with pH = 3.0. The single-crystal X-ray analysis has revealed that 1 crystallizes in monoclinic, space group P21/n with a = 8.4853(8), b = 13.1520 (14), c = 14.3866(12) ?, β = 102.629(3)o, V = 1566.7(3) ?3, C28H26Cl2CuN6O12, Mr = 773.00, Z = 2, Dc = 1.639 g/cm3 , F(000) = 790, μ = 0.942 mm-1, the final R = 0.0438 and wR = 0.1214 for 3165 obser- ved reflections with I > 2σ(I). X-ray analysis shows that compound 1 has unsymmetric chelation of dafone with one Cu–N bond being much longer than the other. Coordination geometry of Cu is a highly distorted octahedron and the whole structure is stabilized by π-π stacking and static attractive forces from [ClO4]- anions. Based on the crystal data, quantum chemistry calculation at the DFT/ B3LPY level was used to reveal the electronic structure of 1.
基金Supported by the 973 key program of the MOST(2010CB933501,2012CB821705)the Chinese Academy of Sciences(KJCX2-YW-319,KJCX2-EW-H01)+1 种基金the National Natural Science Foundation of China(21373221,21221001,91022008,91122027,51172232)the Natural Science Foundation of Fujian Province(2011HZ0001-1,2012J06006,2006L2005)
文摘Hydrothermal reactions of Na2MoO2·2H2O and NH4VO3（or V2O5） with appropriate reducing agents such as organic amines, NH2OH·HCl and Mo（CO）6 gave rise to the formation of a series of capped Keggin derivatives, [N（CH3）4]2Na3（NH4）2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·-13H2O（1）, [NH4]7[（V^VO4）Mo^VI8V^IV4O36（V^IVO）2]·7H2O（2）, [HN（CH2CH2）3NH][（PO4）Mo^V3Mo^VI9O36（V^IVO）2]·-3[N（CH2CH2）3N]·（en）·4.5H2O（3） and [HNH2OH][NH4]2[（V^VO4）Mo^VI8V^IV4O36（V^IVO）4]·24H2O（4）. Single-crystal X-ray diffraction analysis revealed that the anions in 1-3 are two-capped Keggin derivatives with characteristic trans vanadium-oxygen caps, whereas the heteropoly anion in 4 is a tetra-capped α-Keggin derivative with characteristic vanadium-oxygen caps on the equatorial plane.
基金This work was supported by the National Natural Science Foundation of China (20171012) and Natural Science Foundation of Fujian Province (E0110010)
文摘A hydrothermal reaction of 1,3,5-benzene-tricarboxylic acid (H3BTC) with cad- mium acetate, zinc acetate and pyridine led to the formation of pink crystals of [Cd2Zn(BTC)2- (H2O)4]n?2nH2O 1. Single-crystal X-ray diffraction analysis has revealed that 1 (Cd2ZnC18H18O18) crystallizes in the monoclinic system, space group C2/c with a = 19.4328(7), b = 7.1420(3), c = 18.0426(5) ?, β = 118.035(1)o, V = 2210.3(1) ?3, Mr = 812.49, Dc = 2.442 g/cm3, Z = 4, μ(MoKα) = 3.081 mm-1 and F(000) =1584. A total of 10735 reflections were collected, of which 2544 were unique. The structure was refined to R = 0.0200 and wR = 0.0603 for 2388 observed reflections with I>2σ(I). The crystal structure consists of cadmium(II)/zinc(II) carboxylates of BTC as well as coordination and discrete water molecules. Extension of the coordination geometry around three metal centers (Cd(1), Cd(2) and Zn(1)), two BTC3- ligands and four coordinated water molecules generates a three-dimensional coordination polymer.
基金The project was supported by the National Natural Science Foundation of China (20673019)the Specialized Research Fund for the Doctoral Program of Higher Education (20060386001)Fujian Provincial Government (Z0513005, 2005HZ01-2-6)
文摘The reduced SnO2（110） surface has been investigated by using first-principles method with a slab model. By examining the vacancy formation energy of three kinds of reduced SnO2（110） surfaces, the most energetically favorable defect surface is confirmed to be the surface with the coexistence of bridging and in-plane oxygen vacancies, which is different with the traditional model by only removing bridging oxygen. The results of band structure calculations indicate that the electronic structure of this defect surface is similar to the SnO surface.
基金Supported by the 973 Key Program of the MOST (2006CB932904,2007CB815304)the National Natural Science Foundation of China (20873150,20821061,and 50772113)+2 种基金the Chinese Academy of Sciences (KJCX2-YW-M05)the Chinese Academy of Sciences (''Hundred Talents Program'') Ministry of Science and Technology of China (Project of ''973'' plan,No. 2007CB607606),and Shandong Provincial Education Department and Qilu Normal University
文摘Two new polyoxomolybdate compounds,namely CuII2（HL）3]2[Mo8O26]·（H2O）4（1） and [NiII（HL）3]2（Mo8O26）·（H2O）3（2）（HL = 3-（2-pyridyl）pyrazole）,were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu（II） ions linked by three 3-（2-pyridyl）pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-（2-pyridyl）pyrazole ligands.Crystal data of 1：C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850（2）,b = 18.510（4）,c = 17.230（3） ,β = 100.57（3）°,V = 3401.6（12） 3,Z = 4,Dc = 2.324 g/cm3,F（000） = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775（Ⅰ 〉 2σ（Ⅰ））;Crystal data for 2：C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799（2）,b = 14.7970（13）,c = 23.141（2） ,β = 91.6180（10）°,V = 7119.0（11） 3,Z = 4,Dc = 2.077 g/cm3,F（000） = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696（Ⅰ〉 2σ（Ⅰ））.
文摘A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in the triclinic.,space group P1 with ceIl parameters:a=O.90363(2)nm,b=1.25078(3)nm,c=1.41303(1)nm,穋m^(-3),Z=2,Mr=756.72,F(000)=760,Ⅲ)and the approxi-mately oriented octahedrally sixfold-coordinated Fe(Ⅲ)are linked by a cyano-bridge group to construct a dinuclear compound.The{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](Ⅲ)-Fe(Ⅲ)interaction is antiferromagnetic.CCDC:223430.
基金financial supports pro-vided by the National Natural Science Foundation of China(No.21905279)the Natural Science Foundation of Fujian Province(No.2020J05086).
文摘Small-sized Cd_(x) Zn_(1-x) S solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution(PHE),but it still suffers from easy agglomeration,severe photo corrosion,and fast photogenerated electron-hole recombination.To tackle these issues,herein,we propose a new strategy to modify Cd_(x) Zn_(1-x) S nanoreactors by the simultaneous utilization of ionic-liquid-assisted morphology engineering and MXene-incorporating method.That is,we designed and synthesized a novel hierarchi-cal Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction composite through the in-situ deposition of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets on unique IL-modified Ti_(3) C_(2) MXenes by a one-pot solvothermal method for efficiently PHE.The unique construction strategy tailors the thickness of ultrathin Cd_(0.8) Zn_(0.2) S nanosheets and prevents them from stacking and agglomeration,and especially,optimizes their charge transfer pathways during the photocatalytic process.Compared with pristine Cd_(0.8) Zn_(0.2) S nanosheets,Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) has abun-dant photogenerated electrons available on the Ti_(3) C_(2) surface for proton reduction reaction,owing to the absence of deep-trapped electrons,suppression of electron-hole recombination in Cd_(0.8) Zn_(0.2) S and high-efficiency charge separation at the Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) Schottky junction interface.Moreover,the hy-drophilicity,electrical conductivity,visible-light absorption capacity,and surficial hydrogen desorption of Cd_(0.8) Zn_(0.2) S/Ti_(3) C_(2) heterostructure are significantly improved.As a result,the heterostructure exhibits out-standing photocatalytic stability and super high apparent quantum efficiency,being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts.This work illustrates the mechanisms of mor-phology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.
基金financial support of the National Natural Science Foundation of China(NSFC,No.21905278)the Natural Science Foundation of Hunan Province(No.2023JJ30015).
文摘The pore structure and pseudo-graphitic phase(domain size and content)of a hard carbon anode play key roles in improving the plateau capacity of sodium-ion batteries(SIBs),while it is hard to regulate them effectively and simultaneously.This study delves into the synthesis of hard carbons with tailored microstructures from esterified sodium carboxymethyl cellulose(CMC-Na).The hard carbon(EHC-500)with maximized pseudo-graphitic content(73%)and abundant uniformly dispersed closed pores was fabricated,which provides sufficient active sites for sodium ion intercalation and pore filling.Furthermore,minimized lateral width(L_(a))of pseudo-graphitic domains in EHC-500 is simultaneously realized to improve the accessibility of sodium ions to the intercalation sites and filling sites.Therefore,the optimized microstructure of EHC-500 contributes to a remarkable reversible capacity of 340 mAh/g with a high plateau capacity of 236.7 mAh/g(below 0.08 V).These findings underscore the pivotal role of microcrystalline structure and pore structure in the electrochemical performance of hard carbons and provide a novel route to guide the design of hard carbons with optimal microstructures towards enhanced sodium storage performance.
基金financially supported by the National Natural Science Foundation of China (No. 22225902, U22A20436, 22209185)National Key Research&Development Program of China (2022YFE0115900, 2023YFA1507101, 2021YFA1501500)+1 种基金the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences (No. CXZX-2022-GH04, CXZX-2023-JQ08)Science and Technology Program of Fuzhou (2023-P-009)。
文摘Manganese-based chalcogenides have significant potential as anodes for sodium-ion batteries(SIBs) due to their high theoretical specific capacity, abundant natural reserves, and environmental friendliness. However, their application is hindered by poor cycling stability, resulting from severe volume changes during cycling and slow reaction kinetics due to their complex crystal structure. Here, an efficient and straightforward strategy was employed to in-situ encapsulate single-phase porous nanocubic MnS_(0.5)Se_(0.5) into carbon nanofibers using electrospinning and the hard template method, thus forming a necklace-like porous MnS_(0.5)Se_(0.5)-carbon nanofiber composite(MnS_(0.5)Se_(0.5)@N-CNF). The introduction of Se significantly impacts both the composition and microstructure of MnS_(0.5)Se_(0.5), including lattice distortion that generates additional defects, optimization of chemical bonds, and a nano-spatially confined design. In situ/ex-situ characterization and density functional theory calculations verified that this MnS_(0.5)Se_(0.5)@N-CNF allevi- ates the volume expansion and facilitates the transfer of Na+/electron. As expected, MnS_(0.5)Se_(0.5)@N-CNF anode demonstrates excellent sodium storage performance, characterized by high initial Coulombic efficiency(90.8%), high-rate capability(370.5 m Ahg^(-1) at 10 Ag^(-1)) and long durability(over 5000 cycles at 5 Ag^(-1)). The MnS_(0.5)Se_(0.5)@N-CNF//NVP@C full cell, assembled with MnS_(0.5)Se_(0.5)@N-CNF as anode and Na_(3)V_(2)(PO_4)_(3)@C as cathode, exhibits a high energy density of 254 Wh kg^(-1) can be provided. This work presents a novel strategy to optimize the design of anode materials through structural engineering and Se substitution, while also elucidating the underlying reaction mechanisms.
