氧钒(Ⅳ)碱式碳酸铵的热分析和纳米氧化钒的制备

The violet polycrystalline (NH₄)₅[(VO)₆(CO₃)₄(OH)₉]·10H₂O(NVCO) was simply synthesized by solution reaction using V₂O₅, HCl, N₂H₄·2HCl and NH₄HCO₃ as the starting materials. The results of TGA and DTA of NVCO under H₂(99.999%) atmosphere show that V₂O₃ forms at 620℃. The data of TG/DTG and DTA of NVCO under N₂(99.999%) atmosphere indicate that VO₂ forms at 367℃ and crystallizes at 390℃. In air atmosphere, the TG/DTG and DTA of NVCO show that V₂O₅ forms at 354℃, crystallizes at 366℃ and melts at 664℃. The three thermolysis processes of NVCO show that a large amount of H₂O, CO₂ and NH₃ gases fast releases during the thermolysis of NVCO, causing that the particles of the materials split and atomize strongly, thus to obtain V₂O₃, VO₂ and V₂O₅ nano-powders finally. According to the above of thermoanalytical results, V₂O₃, VO₂ and V₂O₅ powders were prepared respectively under H₂, N₂ and oxygen in a tube furnace. Chemical analysis and XRD ex-periments of the powders identify that pure V₂O₃ is obtained at 800℃ for 0.5h under H₂ atmosphere; crystalline VO₂ is obtained at 480℃ for 0.5h in N₂; amorphous VO₂ is obtained at 350℃ for 20min under N₂ atmosphere, this has been first reported to prepare amorphous VO₂ powder so far; pure V₂O₅ is obtained at 400℃ for 10min under oxygen. From the micrographs of the powders, the particle size of the V₂O₃, the crystalline VO₂ or the V₂O₅ powders is 35nm, 24nm or < 40nm, respectively. Above-mentioned results prove that NVCO is a good precursor for preparation of pure V₂O₃, VO₂ and V₂O₅ nano-powders under mild conditions.     

基于钒氧多酸与大环铜配合物构筑的三维配位聚合物的合成与表征

通过[CuL](ClO₄)₂(L=5,12-二甲基-1,8-二乙醇基-1,3,6,8,10,13-六氮杂环十四烷)与NH₄VO₃反应,得到一个钒氧多酸桥联大环铜配合物的三维配位聚合物{[CuL][VO₃]₂·0.67H₂O}_n。并对其进行了元素分析、红外光谱、紫外光谱、热重和X-射线单晶衍射测定。单晶结构测试结果表明配合物属于三方晶系,R3空间群。在晶体结构中,铜原子与大环配体上的四个氮原子和钒氧四面体[VO₄]中的2个氧原子配位,形成畸变的八面体构型。钒氧多酸阴离子[V₆O₁₈]^6-桥联大环配合物[CuL]²⁺形成一个具有一维通道的三维配位聚合物。     

一种新型无机—有机杂化多钒酸化合物[Ni(bpp)2]2(V4O12)[bpp＝ 1,3－联(4－吡啶基)丙烷]的合成与表征

本文以NiCl₂·6H₂O、1,3－联(4－吡啶基)丙烷（bpp）、NH₄VO₃、乙醇、水为原料，采用水热法成功的合成了一种无机－有机杂化多钒酸化合物[Ni(bpp)₂]₂(V₄O₁₂)。该化合物包含彼此互相垂直的二维共价层所形成的二重互穿网络_∞2{Ni(bpp)₂}_n²ⁿ⁺和连接_∞2{Ni(bpp)₂}_n²ⁿ⁺的环形四核簇{V₄O₁₂}^4-。该化合物具有三维网状结构，属于四方晶系，空间群为I4₁/a，晶胞参数是：a = 2.14705 nm, c =1.29293 nm。对[Ni(bpp)₂]₂(V₄O₁₂)的漫反射光谱研究表明，此化合物的光学能隙值约为2.70eV，具有半导体性质。     

钒氧化物催化CO2氧化异丁烷脱氢的研究

采用溶胶-凝胶法制备了一系列钒氧化物催化剂,并用于CO₂氧化异丁烷脱氢反应. 采用X射线衍射、低温N₂吸附-脱附、O₂程序升温氧化、程序升温表面反应和原位傅里叶变换红外光谱等方法研究了催化剂的性质. 反应结果表明,尽管所有钒氧化物催化剂的丁烯选择性都大于85%,但随着催化剂组成和制备方法的改变,催化活性和稳定性差异显著. 其中,12 wt% V₂O₅/Ce_0.6Zr_0.4O₂（7 wt%）-Al₂O₃的催化活性最高,而6 wt% V₂O₅-Ce_0.6Zr_0.4O₂（7 wt%）-Al₂O₃的稳定性最佳. 关联分析催化反应结果与催化剂表征表明,钒氧化物的催化活性取决于VO_x物种的结晶度和分散度,而催化剂表面所积重质焦炭的特性是决定催化剂稳定性的关键. 非稳态反应和原位光谱结果确认,CO₂氧化异丁烷脱氢遵循Mars-van Krevelen氧化还原机理.     

表面修饰的钒氧化物纳米带上甲苯选择氧化反应

采用声化学水热法制备了V₂O₅纳米带,并将十六烷基膦酸负载在它和块状V₂O₅表面上,以修饰催化剂表面,通过调变催化剂中晶格氧活动性以及表面酸碱性来控制其催化甲苯氧化产物的选择性.结果表明,V₂O₅纳米带具有较强的晶格氧活动性,与普通块状V₂O₅相比,甲苯转化率更高,但苯甲醛和苯甲酸的总选择性下降.经过表面修饰后,V₂O₅纳米带的催化活性以及苯甲醛、苯甲酸总选择性增加;而块状V₂O₅上苯甲醛、苯甲酸总选择性更高,但催化活性显著下降.     

VOx / Titanate复合材料纳米棒的水热合成及其电化学性能研究

Vanadium oxide/titanate composites nanorods (VO_x/ Titanate-CNRs) were synthesized in high yield by using titanate nanotubes as templates and V₂O₅·nH₂O sol as the precursors under hydrothermal conditions (200 ℃, 48 h). Samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive analysis by X-ray (EDAX). X-ray diffraction structure determination showed that this new phase had the composition of V₃O₇·H₂O and crystallized with orthorhombic symmetry. SEM and TEM tests showed that the samples were uniform straight rods with the diameter range from around 100 to 300 nm and the length over 10 μm. The chemical compositions of the samples were determined with EDXA. The electrochemical tests of samples (titanates nanotubes, V₂O₅ and VO_x/ Titanate-CNRs) prove that VO_x/ Titanate-CNRs exhibit a better electrochemical performance.     

含钒多金属氧酸盐的抑菌活性

按文献方法合成了α-Na₁₀[PW₉V₃(H₂O)₃O₃₇]·16H₂O、α-Na10[PW11V(H₂O)O₃₇]·16H₂O和[H₃O]₃[NH₄]₁₈[Mo₅₇V₆O₁₈₃(NO)₆(H₂O)₄₈]·56H₂O（分别简称α-PW₉V₃、α-PW₁₁V和Mo₅₇V₆）含V多金属氧酸盐。 采用纸片法分别测试了它们对大肠杆菌、枯草芽孢杆菌、酵母菌和黑曲霉菌的抑菌活性。 3种化合物均有不同程度的抑菌作用, 其中α-PW₁₁V的抑菌效果最好。     

钒卤代过氧化物酶构象模型分子的设计、合成及仿生催化活性

基于钒卤代过氧化物酶(V-HPOs)活性中心的N、O配位环境及活性中心与氨基酸残基、水分子之间的氢键作用的模拟, 我们设计、合成了两种钒氧配合物: (C₃H₅N₂)₂[(VO)₂(μ₂-C₂O₄)(C₂O₄)₂(H₂O)₂] (1)和(VO₂)₂(μ₂- C₂O₄)(C₂H₄N₂)₂ (2), 并通过X射线单晶衍射方法确定了它们的结构. 晶体结构分析表明上述钒氧配合物的配位环境与(V-HPOs)活性中心十分相似, 且在配合物的三维堆积结构中具有类α-螺旋结构. 溴化反应活性研究发现这些钒氧配合物在仿生催化实验中表现出较高的催化活性.     

具有经典ACO拓扑开放结构的三维多孔多钒氧酸盐的水热合成和晶体结构

本文采用水热技术合成了一种具有经典ACO拓扑结构的多钒氧酸盐{[Cu₄(V^Ⅳ₁₁V^Ⅴ₇O₄₂(PO₄))(C₃H₁₀N₂)₈]·4H₂O}_n (1,C₃H₁₀N₂=1,2-丙二胺),并且通过元素分析、红外、热重、单晶X-射线衍射对化合物1进行了表征。晶体学分析表明,阴离子簇[V^Ⅳ₁₁V^Ⅴ₇O₄₂(PO₄)]^8-与8个过渡金属配合物阳离子[Cu(C₃H₁₀N₂)₂]²⁺相连而产生具有经典ACO拓扑结构的三维孔道结构。化合物1为四方晶系,P4/nnc空间群,a=b=1.505 91(10) nm,c=1.871 3(3) nm,V=4.243 8(7) nm³,Z=2。化合物1沿c轴方向具有0.753 nm×0.753 nm孔道。     

钒磷酸盐(NH3CH2CH2NH2)[VOPO4]的水热合成和结构表征

标题化合物是在反应物摩尔比为V₂O₅∶H₃PO₄∶H₂NCH₂CH₂NH₂∶H₂O＝0.55∶4∶3.6∶265时, 175 ℃水热反应5 d合成的. 其结构特点是: 钒八面体[VO₅N]共用角顶的氧形成“之”字型链, 链间由[PO₄]共角顶连接成层; 乙二胺分子的一个N直接与V配位, 并伸向层间. 相邻层间存在强氢键. 晶体学数据: 单斜晶系, P2₁/c (No. 14), a＝0.92108(2) nm, b＝0.72851(1) nm, c＝0.98204(2) nm, β＝101.269(7)°, V＝0.6462(4) nm³, Z＝4, D_c＝2.303 g•cm^－3, R₁＝0.0417, wR₂＝0.0999.     

不同磺化度下的磺化聚醚醚酮对全钒储能液流电池性质影响的研究

本文报道了采用浓硫酸作为磺化剂,成功合成了不同磺化度下的聚醚醚酮(PEEK)膜,并深入研究了磺化条件包括磺化时间和磺化剂的用量对所获薄膜性能的影响,获得了在不同磺化度（DS）下SPPEK膜的离子交换容,含水率,机械性能,质子电导率等参数,特别测定了在全钒液流电池工作条件下钒离子(Ⅳ)渗透率,首次为该类液流储能电池使用价廉质优的质子交换膜提供了基础实验数据。室温条件下的实验结果如下：1）磺化12小时后,膜的磺化度46%,含水量为28%,钒离子(Ⅳ)选择性最佳（钒离子渗透率为1.2×10-7 cm2/min-1,是Nafion117 (2.9×10-6 cm2/min-1)的1/24）,其质子电导率只有0.02 S/cm;2）磺化96小时其磺化度达79%的膜,质子电导率达0.16 S/cm,是Nafion117 (0.10S/cm) 的1.6倍, 但其机械性能最差;3）与Nafion117膜相比,磺化在36到48小时的SPPEK膜其机械力学性能好,薄膜的钒离子渗透率、离子交换容IEC、质子导电率和含水率高,且对钒离子的选择性佳,尤其价格仅为Nafion膜的1/13,是理想的Nafion膜的代替物,可望直接应用于全钒氧化还原液流（VRB）电池中。本文还讨论了磺化时间和不同磺化剂量对膜的性质的影响。     

全钒液流电池碳电极材料的研究进展

近年来,全钒液流电池作为一种大规模储能装置,其电极材料得到了广泛的研究,并且获得了一定的进展.本文简述了全钒液流电池对电极材料的要求,综述了其电极材料的研究进展,重点介绍了碳电极及其改性方面的工作,并对其电极材料的发展趋势进行了展望.     

Towards High Performance Chemical Vapour Deposition V2O5 Cathodes for Batteries Employing Aqueous Media

The need for clean and efficient energy storage has become the center of attention due to the eminent global energy crisis and growing ecological concerns. A key component in this effort is the ultra-high performance battery, which will play a major role in the energy industry. To meet the demands in portable electronic devices, electric vehicles, and large-scale energy storage systems, it is necessary to prepare advanced batteries with high safety, fast charge ratios, and discharge capabilities at a low cost. Cathode materials play a significant role in determining the performance of batteries. Among the possible electrode materials is vanadium pentoxide, which will be discussed in this review, due to its low cost and high theoretical capacity. Additionally, aqueous electrolytes, which are environmentally safe, provide an alternative approach compared to organic media for safe, cost-effective, and scalable energy storage. In this review, we will reveal the industrial potential of competitive methods to grow cathodes with excellent stability and enhanced electrochemical performance in aqueous media and lay the foundation for the large-scale production of electrode materials.     

提升二维材料的电催化析氢和光催化析氢性能的策略

世界能源危机问题和环境问题日益突出,寻找低廉、易得且能够替代化石的清洁能源是目前研究的热点.氢气具有可再生性、安全、高能量密度、环境友好型等优点,因而成为替代化石燃料的首选.在众多途径中,电催化产氢和光催化产氢是目前应用较广且比较成熟的方法,其工艺过程简单、无污染,但由于效率较低或生产成本较高等因素,其大规模应用受到一定的限制.因此,开发高效的析氢催化剂意义重大.迄今为止,贵金属铂是公认的最好的析氢催化剂,但其稀有性和价格高阻碍了大规模的商业应用.因此,寻找高效、稳定、价格合理的析氢催化剂迫在眉睫.近年来,已研究和设计了很多析氢催化材料,其中,二维材料以其独特的物理化学性质(如电子在二维空间内快速移动、超薄结构、较大的比表面积等)引起了科学家的兴趣.但实际研究的二维材料的析氢性能与理论值相比还有很大的差距.因此,提高二维材料的导电性、增加活性位点、提高光电催化剂的循环稳定性是提升其性能的关键.本文综述了四种二维材料(二硫化钼、石墨烯、过渡金属碳氮化物、黑磷)在析氢方面的最新研究进展,包括(1)二维材料的合成方法,(2)二维材料析氢性能,(3)析氢催化机理.并从三个方面总结了提升二维材料析氢性能的策略:(1)缺陷位工程,(2)异质结策略,(3)金属及非金属杂原子掺杂.在提高二维材料的策略方面,本文着重讨论了d带理论、状态密度和费米能级,为更多二维析氢催化材料的制备提供了有效的指导.最后,本文分析了二维催化剂领域目前面临的问题和挑战,展望了未来的发展趋势.     

A Deep‐Cycle Aqueous Zinc‐Ion Battery Containing an Oxygen‐Deficient Vanadium Oxide Cathode

Rechargeable aqueous zinc‐ion batteries are attractive because of their inherent safety, low cost, and high energy density. However, viable cathode materials (such as vanadium oxides) suffer from strong Coulombic ion–lattice interactions with divalent Zn²⁺, thereby limiting stability when cycled at a high charge/discharge depth with high capacity. A synthetic strategy is reported for an oxygen‐deficient vanadium oxide cathode in which facilitated Zn²⁺ reaction kinetic enhance capacity and Zn²⁺ pathways for high reversibility. The benefits for the robust cathode are evident in its performance metrics; the aqueous Zn battery shows an unprecedented stability over 200 cycles with a high specific capacity of approximately 400 mAh g^?1, achieving 95 % utilization of its theoretical capacity, and a long cycle life up to 2 000 cycles at a high cathode utilization efficiency of 67 %. This work opens up a new avenue for synthesis of novel cathode materials with an oxygen‐deficient structure for use in advanced batteries.     

Oxovanadium(V) tetrathiacalix[4]arene complexes and their activity as oxidation catalysts

With the aim of modeling reactive moieties and relevant intermediates on the surfaces of vanadium oxide based catalysts during oxygenation/dehydrogenation of organic substrates, mono- and dinuclear vanadium oxo complexes of doubly deprotonated p-tert-butylated tetrathiacalix[4]arene (H4TC) have been synthesized and characterized: PPh4[(H2TC)VOCl(2)] (1) and (PPh4)2[{(H2TC)V(O)(mu-O)}2] (2). According to the NMR spectra of the dissolved complexes they both retain the structures adopted in the crystalline state, as revealed by single-crystal X-ray crystallography. Compounds 1 and 2 were tested as catalysts for the oxidation of alcohols with O(2) at 80 degrees C. Both 1 and 2 efficiently catalyze the oxidation of benzyl alcohol, crotyl alcohol, 1-phenyl-1-propanol, and fluorenol, and in most cases dinuclear complex 2 is more active than mononuclear complex 1. Moreover, the two thiacalixarene complexes 1 and 2 are in many instances more active than oxovanadium(V) complexes containing "classical" calixarene ligands tested previously. Complexes 1 and 2 also show significant activity in the oxidation of dihydroanthracene. Further investigations led to the conclusion that 1 acts as precatalyst that is converted to the active species PPh4[(TC)V==O] (3) at 80 degrees C by double intramolecular HCl elimination. For complex 2, the results of mechanistic investigations indicated that the oxidation chemistry takes place at the bridging oxo ligands and that the two vanadium centers cooperate during the process. The intermediate (PPh4)2[{H2TCV(O)}2(mu-OH)(mu-OC13H9)] (4) was isolated and characterized, also with respect to its reactivity, and the results afforded a mechanistic proposal for a reasonable catalytic cycle. The implications which these findings gathered in solution may have for oxidation mechanisms on the surfaces of V-based heterogeneous catalysts are discussed.     

动力锂离子电池正极材料磷酸钒锂制备方法

锂离子电池新型正极材料的开发是当前的研究热点,其中磷酸盐材料以其结构稳定、安全性能好及资源丰富等优点备受关注。磷酸钒锂理论能量密度可达500mWh/g,具有较高的电子离子导电性、理论充放电容量及充放电电压平台,被认为是一种极具竞争优势和应用前景的动力锂离子电池正极材料。传统磷酸钒锂合成方法有固相合成法、碳热还原法、溶胶凝胶法和水热合成法等,近年来,又出现了湿法固相配位法、微波固相合成法和流变相法等新型合成方法。本文简要介绍了磷酸钒锂的结构和性能特点,对磷酸钒锂制备方法的最新研究进展进行了较为全面的阐述,并详细介绍了本研究团队近年来在磷酸钒锂材料新型合成方法方面的探索成果。同时对各种合成方法的制备工艺及材料性能进行了对比分析,并探讨了当前存在的问题及未来的研究方向。     

钼掺杂Li3V2（PO4）3/C正极材料的制备及其电化学性能研究

以Li2CO3、NH4H2PO4、V2O5和MoO3为原料,柠檬酸为络合剂和碳源,采用溶胶-凝胶法制备了锂离子正极材料Li3MoxV2-x(PO4)3/C(x=0.01,0.02,0.03).X射线衍射(XRD)表明,合成的材料具有单一的单斜晶系结构,空间群为P21/n.扫描电镜(SEM)显示Li3Mo0.02V1.98(PO4)3/C具有均一的表面形貌.恒流充放电测试表明,当x=0.02时,掺杂后的Li3Mo0.02V1.98(PO4)3具有最佳的电化学性能.在1C倍率下,3.0～4.3 V电位区间,Li3Mo0.02V1.98(PO4)3/C的首次放电比容量达到122.3 mAh.g-1,循环50周之后,容量没有衰减的迹象;而当x=0、0.01和0.03时,首次放电比容量仅分别为117.1、115.1和116.0 mAh.g-1.在3C和5C倍率下,样品Li3Mo0.02V1.98(PO4)3/C仍能保持优异的循环稳定性.     

An Exceptional Peroxide Birefringent Material Resulting from d–π Interactions

Birefringent materials, which can modulate the polarization of light, are almost exclusively limited to oxides. Peroxides have long been overlooked as birefringent materials, because they are usually not stable in air. Now, the first peroxide birefringent material Rb₂VO(O₂)₂F is reported, the single crystals of which keep transparency after being exposed in the air for two weeks. Interestingly, Rb₂VO(O₂)₂F does not feature an optimal anisotropic structure, but its birefringence (Δn=0.189 at 546 nm) exceeds those of the majority of oxides. According to the first-principles calculations, this exceptional birefringence should be attributed to the strong electronic interactions between localized π orbital of O₂²⁻ anions and V⁵⁺ 3d orbitals, which may be also favorable to the stability in the air for Rb₂VO(O₂)₂F. These findings distinguish peroxides as a brand-new class of birefringent materials that may possess birefringence superior to the traditional oxides.     

钼掺杂磷酸钒锂正极材料的制备及其电化学性能研究

以Li2CO3,NH4H2PO4,V2O5和MoO3为原料,柠檬酸为络合剂和碳源,采用溶胶凝胶法制备了锂离子正极材料Li3MoxV2-x(PO4)3/C (x = 0.01, 0.02和0.03). X射线衍射（XRD）表明,合成的材料具有单一的单斜晶系结构,空间群为P21/n. 扫描电镜（SEM）显示Li3Mo0.02V1.98(PO4)3/C具有均一的表面形貌。恒流充放电测试表明,当x = 0.02时,掺杂后的Li3Mo0.02V1.98(PO4)3具有最佳的电化学性能. 在1C倍率下,3.0 ~ 4.3 V电位区间,Li3Mo0.02V1.98(PO4)3/C的首次放电比容量达到122.3 mAh?g-1,循环50周之后,容量没有衰减的迹象;而当x = 0, 0.01和0.03时,首次放电比容量仅分别为117.1 mAh?g-1,115.1 mAh?g-1和116.0 mAh?g-1. 在3C和5C倍率下,样品Li3Mo0.02V1.98 (PO4)3/C仍能保持优异的循环稳定性.