杂多酸离子液体负载氨基化Fe3O4磁性复合材料的制备及其超声辅助催化脱硫性能

以N-甲基咪唑、溴代正丁烷、磷钨酸为原料制备了1-丁基-3-甲基咪唑磷钨酸离子液体[BMIM]₃PW₁₂O₄₀,将其通过超声浸渍法负载于氨基化Fe₃O₄（Fe₃O₄-NH₂）,得到枣糕型结构的[BMIM]₃PW₁₂O₄₀/Fe₃O₄-NH₂磁性复合材料,通过FTIR、XRD、XPS、TEM、振动样品磁强计（VSM）、SEM等对其组成、形貌等进行表征。以[BMIM]₃PW₁₂O₄₀/Fe₃O₄-NH₂磁性复合材料为催化剂,以H₂O₂为氧化剂,催化氧化以二苯并噻吩为硫源的正辛烷模拟油样,通过单因素法分别考察了超声时间、H₂O₂用量、反应温度和催化剂用量等因素对脱硫效果的影响,并初步探讨了[BMIM]₃PW₁₂O₄₀/Fe₃O₄-NH₂磁性复合材料催化脱硫机制。结果表明:0.5 g/L[BMIM]₃PW₁₂O₄₀/Fe₃O₄-NH₂磁性复合材料超声辅助催化氧化浓度为500 mg/g模拟油样,在323 K下H₂O₂与二苯并噻吩的摩尔比n（O）:n（S）为8:1经超声10 min时,催化脱硫率达到最佳,为88.13%;重复使用5次后,[BMIM]₃PW₁₂O₄₀/Fe₃O₄-NH₂磁性复合材料对模拟油样的催化降解率仅下降了2.51%。说明该材料具有良好的催化脱硫性能,并可重复使用。催化机制初步研究表明,活性中心可能为杂多酸阴离子、Fe₃O₄-NH₂和离子液体分别起到载体和协同增容作用。      

溴化1-乙基-3-甲基咪唑氯化锌离子液体的合成、表征及催化性能

采用溴代乙烷与N-甲基咪唑为原料合成了中间体溴化1-乙基-3甲基咪唑,并与氯化锌反应制备了1-乙基-3-甲基溴化咪唑氯化锌盐。分别经1 HNMR、FT-IR、TG、DSC对离子液体进行了结构表征及热分析。将该离子液体用于尿素醇解合成碳酸二乙酯反应体系,考查了[EMIM][Br][Zn2Cl4]离子液体的催化性能,碳酸二乙酯的收率超过25%。     

典型螺栓连接CFRP薄壁C型柱轴压失效行为:试验及数值模拟

为了研究典型螺栓连接碳纤维增强树脂复合材料(CFRP)薄壁C型柱的轴压失效模式及吸能特性,进行了5组不同铺层方式C型柱的准静态轴压试验,即[0/90]_4s、[±45]_4s、[±45/90₂/0₄]_s、[±45/90/0₂/90/0₂]_s、[90/±45/0]_2s,获得其失效形貌及载荷-位移曲线。采用Lavadèze单层壳单元模型、Puck-Yamada失效准则、层间胶粘单元及螺栓模型,建立C型柱层合壳模型进行轴压仿真,并与试验失效形貌、载荷-位移曲线及吸能特性评估指标进行对比分析。结果表明:0°、±45°、90°纤维可以显著影响C型柱轴压失效模式及吸能特性。在轴压载荷下,±45°纤维铺设C型柱发生局部屈曲失效模式,吸能特性差。±45°纤维铺设在外部,0°和90°纤维交替铺设在内部的C型柱,其轴压失效过程平稳,吸能特性好。与C型柱轴压试验结果相比,层合壳模型获得的整体变形和局部失效形貌吻合较好,载荷-位移曲线变化趋势和吸能特性评价指标基本一致。研究结果对CFRP薄壁C型柱吸能设计具有一定的指导意义。      

离子液体对可磁分离TiO2光催化材料结构和性能的影响

采用溶胶-凝胶法分别在离子液体1-丁基-3-甲基咪唑四氟硼酸盐[BMim]BF₄、1-丁基-吡啶四氟硼酸盐[BPy]BF₄和1-丁基-3-甲基咪唑醋酸盐[BMim]Ac的辅助下制备可磁分离TiO₂/CoFe₂O₄(TCF)光催化材料, 采用X射线衍射分析(XRD)、N₂吸附-脱附分析(BET)和透射电子显微镜(TEM)研究了离子液体结构对可磁分离TiO₂的结构和性能的影响。结果显示: 200 ℃焙烧后样品[BMim]BF₄-TCF和[BPy]BF₄-TCF有锐钛矿相TiO₂ 生成, 而样品[BMim]Ac-TCF和TCF只有经400 ℃焙烧才出现锐钛矿相的衍射峰。当焙烧温度为800 ℃时, 样品[BMim]BF₄-TCF主要以锐钛矿相TiO₂存在(相对含量为92.6%), 说明离子液体中含有[BF₄^-]基团能降低锐钛矿相的晶化温度和能提高锐钛矿相高温稳定性。400 ℃焙烧后[BMim]BF₄-TCF和[BPy]BF₄-TCF的比表面积分别为125.7和120.3 m²/g, 高于[BMim]Ac-TCF(77.8 m²/g)和不加离子液体所制备样品TCF(63.7 m²/g)。说明阴离子BF₄^-有利于形成较大比表面积的TiO₂。在模拟太阳光照射120 min后, 经400 ℃焙烧后的样品[BMim]BF₄-TCF、[BPy]BF₄-TCF、[BMim]Ac- TCF对亚甲基蓝的降解速率分别为96%、87%、64%。     

二维碳化钛/碳纳米管负载铂钌粒子的制备及电催化性能研究

直接甲醇燃料电池因操作方便、转化效率高、操作温度低、污染少以及液体燃料易存储易运输等优势具有良好的应用前景, 但现有阳极催化剂存在催化活性低、抗CO中毒性差等缺点, 制约了其商业化应用前景。本研究采用三步法制备得到了一系列不同Pt、Ru配比的PtRu/(Ti₃C₂T_x)_0.5-(MWCNTs)_0.5阳极催化剂材料, HF腐蚀Ti₃AlC₂得到Ti₃C₂T_x, 与酸化处理的多壁碳纳米管(MWCNTs)复合后通过溶剂热法负载Pt、Ru颗粒。通过XRD、SEM、EDS、TEM、XPS等分析铂钌的协同关系。结果表明: Ru原子与Pt原子晶格混合, 形成了粒径约3.6 nm的铂钌双金属合金。电化学分析结果表明: Pt₁Ru_0.5/(Ti₃C₂T_x)_0.5-(MWCNTs)_0.5催化剂具有最佳的电化学性能, 其电化学活性面积(Electrochemical Active Area, ECSA)为139.5 m ²/g, 正向峰电流密度为36.4 mA/cm ²。     

高质量水系钠离子电池正极Fe4[Fe(CN)6]3的合成及其电化学性能

采用水热法合成高质量的Fe₄[Fe(CN)₆]₃(HQ-FeHCF)纳米材料, 并对材料进行X射线衍射(XRD), 扫描电子显微镜(SEM), 透射电子显微镜(TEM)和热重分析测试(TGA)等表征。结果表明：Fe₄[Fe(CN)₆]₃呈规则立方体, 颗粒大小约500 nm, 属面心立方结构。Fe₄[Fe(CN)₆]₃在NaClO₄-H₂O-聚乙二醇电解液中1C、2C、5C、10C、20C、30C和40C的容量分别为124、118、105、94、83、74和64 mAh·g ^-1, 表现出优异的倍率性能; 以5C倍率循环500次, 容量保持率接近100%, 表现出极佳的循环稳定性。以Fe₄[Fe(CN)₆]₃和磷酸钛钠分别为正负极的全电池工作电压高达1.9 V, 能量密度可达126 Wh·kg ^-1; 以5C倍率恒流充放电测试140次后全电池容量保持率为92%, 且库伦效率始终接近100%。     

铺层顺序对复合材料薄壁圆管轴向压溃吸能特性的影响研究

采用仿真和试验相结合的方法探讨复合材料薄壁圆管在准静态轴向压缩载荷下的失效吸能特性和吸能机理。首先,建立复合材料薄壁圆管"层合壳"有限元模型,通过显式动力学方法求解其在准静态轴向载荷下的压溃失效力学行为。仿真与试验结果在圆管轴向压溃变形过程、初始峰值载荷、平均压溃载荷及比吸能等主要吸能参数上具有很好的一致性,验证了"层合壳"复合材料圆管有限元模型和建模方法的有效性。其次,采用解析模型与仿真分析方法分别对[0/90]_3s、[0/90/0₂/90₂]_s、[0₃/90₃]_s三种不同铺层顺序的复合材料圆管的屈曲载荷与吸能特性进行了对比,进一步分析了铺层顺序对圆管失效吸能特性的影响。研究表明,0°与90°铺层交替程度对复合材料圆管的吸能特性影响较大,保证纤维失效方式在结构宏观失效中占主导地位能够提高材料失效吸收能量。     

偶氮苯基小分子光控聚N-异丙基丙烯酰胺在离子液体中的自组装

偶氮苯基材料因其具有可逆的光致顺反异构特性,可调控聚合物的自组装行为而受到广泛关注。采用不同结构且广泛商业化的偶氮苯基小分子(偶氮苯(AZO)、对羟基偶氮苯(AZO-OH)、对氨基偶氮苯(AZO-NH₂)、二甲基黄[AZO-N(CH₃)2_])作为光分子开关,控制聚N-异丙基丙烯酰胺(PNIPAm)在1-乙基-3-甲基咪唑双(三氟甲基磺酰基)亚胺([C₂mim][NTf₂])离子液体中的自组装行为,探讨不同偶氮苯基末端基元对于PNIPAm自组装相行为的影响。结果表明,偶氮苯基小分子均能有效调控PNIPAm在[C₂mim][NTf₂]离子液体中的相变响应行为,但不同的末端基元对于PNIPAm的相变温度及相变区间影响甚微。结合原位变温红外谱图分析可知,紫外光照强化了PNIPAm与离子液体之间的相互作用,从而抑制了PNIPAm侧链间的相互聚集,这将促进紫外光照条件下“溶剂化”效应的发生,可获得更低的相变温度。     

基于Cu3(HHTP)2薄膜的离子液体电致变色电极

室温离子液体具有宽电化学窗口和良好的环境稳定性, 是电致变色器件的理想电解质。然而传统电致变色材料的晶格间隙较窄, 限制了离子液体中大尺寸离子的扩散, 且大离子反复脱/嵌会破坏传统电致变色材料的结构, 导致性能衰减。金属有机框架材料(MOFs)是一种具有拓扑结构的多孔晶态材料, 有望为离子液体中大尺寸离子的传输提供通道。本工作在导电玻璃表面制备了三亚苯类Cu₃(HHTP)₂ (HHTP=2,3,6,7,10,11-六羟基三苯并菲) MOF薄膜, 并研究了Cu₃(HHTP)₂薄膜在离子液体电解质中电化学和电致变色行为和性能。结果表明, 相对于传统的LiClO₄/PC和NaClO₄/PC电解质, Cu₃(HHTP)₂薄膜在离子液体[EMIm]BF₄中表现出更低的接触电阻和更高的离子扩散效率, 电极的着色/褪色速度得到了显著提高(着色时间由10.3 s缩短至8.0 s, 褪色时间由23.6 s缩短至5.2 s)。同时, Cu₃(HHTP)₂薄膜在[EMIm]BF₄中也具有更高的光调制范围和着色效率。这项工作展现出MOFs/离子液体电化学体系在电致变色领域中的潜在应用价值。     

High proton conductivity in metalloring-cluster based metalorganic nanotubes

Two novel anionic single-walled metal-organic nanotubes(MONTs),[(CH₃)₂NH₂][ln(cdc)(thb)].2DMF.9.5H₂O(FJU-105)and[(CH₃)₂NH₂][ln(cdc)(H-btc)]-2DMA·11H₂O(FJU-106)(H₂cdc=9H-carbazole-3,6-dicarboxylic acid,H₂thb=2,5-thiophene dicarboxylic acid,H3btc=1,3,5-benzene tricarboxylic acid),are achieved by employing[ln₆(cdc)₆]⁶⁺metalloring cluster with largest diameter as the secondary building blocks(SBUs).The inner surface of FJU-106 is functionalized by uncoordinated-COOH groups of the H-btc linkers,leading to a higher proton conduction than FJU-105.At 70℃,FJU-106 displays the proton conduction performances among MONTs,up to 1.80×10^-2S·cm(^-1).And FJU-105 and FJU-106 are the first examples of MONT proton conductors operating at subzero temperature.     

Simulation and Experimental Study on Thermal Conductivity of [EMIM][DEP] + $$\mathbf{H}_\mathbf{2}{} \mathbf{O}$$ + SWCNTs Nanofluids as a New Working Pairs

In this paper, the single-wall carbon nanotubes (SWCNTs) were dispersed into ionic liquid, 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), and its aqueous solution [EMIM][DEP](1) + \(\hbox {H}_{2}\hbox {O}(2)\) to enhance the thermal conductivity of base liquids, which will be the promising working pairs for absorption heat pumps and refrigerators. The enhancement effects on thermal conductivity were studied by experiment and molecular dynamic simulation (MD) methods. The thermal conductivities of [EMIM][DEP] + SWCNTs (INF) and [EMIM][DEP](1) + \(\hbox {H}_{2}\hbox {O}(2)\) + SWCNT(SNF) both with SWCNT mass fraction of 0.5, 1, and 2 (wt%) were measured by transient hot-wire method. The results indicate that the enhancement ratio of thermal conductivity of INF, and SNF can approach 1.30 when SWCNT is 2 (wt%). Moreover, SWCNTs has a higher enhancement ratio than multi-wall carbon nanotubes (MWCNTs). Density and thermal conductivity of [EMIM][DEP], [EMIM][DEP](1) + \(\hbox {H}_{2}\hbox {O}(2)\), INF and SNF systems, together with self-diffusion coefficients of \(\hbox {[EMIM]}^{+}\), \(\hbox {[DEP]}^{-}\), [EMIM][DEP] and water in solution [EMIM][DEP](1) + \(\hbox {H}_{2}\hbox {O}(2)\), were investigated by MD simulations. The results indicate that the maximum relative error between the simulated and experimental densities is about 2 %, and the simulated self-diffusion coefficient of [EMIM][DEP] is in the order of magnitude of \(10^{-11}\,\hbox {m}^{2}\cdot \hbox {s}^{-1}\). The average relative deviation for the simulated thermal conductivity of [EMIM][DEP](1) + \(\hbox {H}_{2}\hbox {O}(2)\), INF and SNF from experimental ones are 23.57 %, 5 %, and 5 %, respectively. In addition, the contributions of kinetic energy, potential energy, and virial and partial enthalpy terms to thermal conductivity were also calculated. The results indicate that virial term’s contribution to thermal conductivity is the maximum, which accounts for 75 % to 80 % of total thermal conductivity.     

Langmuir–Blodgett films of substituted bis(naphthalocyaninato) rare earth complexes: structure and interaction with nitrogen dioxide

Ordered molecular assemblies of novel alkylthio-substituted bis(naphthalocyaninato) rare earth complexes M[2,3-Nc(SC₁₂H₂₅)₈]₂ (M=Gd, Er) have been fabricated by Langmuir–Blodgett (LB) technique and characterized by surface pressure-area isotherm measurements, electronic absorption and polarized electronic absorption spectroscopy and low-angle X-ray diffractometry. The interaction between the thin films and NO₂ gas was investigated. The experimental results indicate that the bis(naphthalocyaninato) rare earth molecules form well-ordered stable monolayers with face-to-face orientation for the macrocycles and edge-on configuration for the molecules at the air–water interface and lamellar multilayers on solid substrates. The orientation angles of naphthalocyanine rings with respect to the quartz plate surface in the LB films for M[2,3-Nc(SC₁₂H₂₅)₈]₂ with M of Gd and Er have been determined based on the polarized absorbance and found to be 50° and 54°, respectively. The adsorption–desorption process of NO₂ on LB films of M[2,3-Nc(SC₁₂H₂₅)₈]₂ has been monitored by electronic absorption spectroscopy. A process of gas desorption was found to obey the Elovich equation.     

Biomimetic ion-channel sensors based on host-guest molecular recognition in Langmuir-Blodgett membrane assemblies

Biomimetic “ion-channel sensors” based on host-guest molecular recognition were constructed by incorporating several kinds of receptor molecules in Langmuir-Blodgett (LB) molecular assemblies deposited directly on glassy carbon electrodes. The receptors used were valinomycin, bis(crown ether)s, macrocyclic polyamine and cyclodextrin polyamine. The binding of charged stimulants (metal ions, inorganic and organic anions) to these receptors induced a marked increase (or decrease) in the ion permeability of the membranes, as detected by cyclic voltammetry using [Fe(CN)₆]^4- or [Ru(bpy)₃]²⁺ as marker ion. Such a mode of response, corresponding to model “channel opening (or closing)”, can be explained on the basis of the charge-charge interaction involving the stimulant, marker ion and lipid.     

Effects of spacer-chain length on the photoelectrochemical responses of monolayer assemblies with ruthenium tris(2,2′-bipyridine) - viologen linked disulfides

Photochemical and photoelectrochemical properties of ruthenium tris(2,2′-bipyridine) (Ru²⁺)-viologen (V²⁺) linked disulfides [RuCnVC₆S]₂ (n (number of methylene groups)=3, 7) with different spacer-chain lengths and Ru²⁺ disulfides [RuC_mS]₂ (m=13, 17) were compared. The luminescence intensity in CH₃CN was in the order of [RuC₁₃S]₂≈[RuC₁₇S]₂>[RuC₇VC₆S]₂[RuC₃VC₆S]₂, implying efficient photoinduced electron-transfer between Ru²⁺ and V²⁺ moieties in the linked compounds. The monolayer assembly of the compound was fabricated on a gold surface. In the presence of triethanolamine, the anodic photocurrent was clearly observed from the RuC_nVC₆S/Au (n=3, 7) electrode (gold electrode modified with [RuCnVC₆S]₂), and its intensity was substantially larger for n=7 than for n=3. Photocurrent action spectra for the RuC_nVC₆S/Au (n=3, 7) electrodes were well correlated with the corresponding electronic absorption spectra in solution. The photocurrent from the RuC₇VC₆S/Au electrode was reduced more effectively by the coexistence of a water-soluble viologen as compared with the RuC₃VC₆S/Au electrode. The photocurrent from the RuC_mS/Au (m=13, 17) electrode was very small. The results suggest that the spacer-chain length between the Ru²⁺ and the V²⁺ moieties profoundly affects the Ru²⁺-sensitized photocurrent.     

酚醛树脂原位催化裂解制备低维碳纳米结构

以Ni（NO₃）₂·6H₂O为催化剂前躯体,原位催化裂解酚醛树脂制备了碳洋葱、竹节碳和碳纳米管等低维碳纳米结构;用粉体X-射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）等手段对低维碳纳米结构进行了表征。结果表明;当Ni（NO₃）₂·6H₂O与苯酚物质量比小于0.01时,Ni催化剂易分散,碳纳米管易生成,管径均一、分布稠密;当Ni（NO₃）₂·6H₂O与苯酚物质量比大于0.04时,Ni催化剂易团聚,碳纳米管管径分布较宽,分布稀疏;当Ni（NO₃）₂·6H₂O与苯酚物质量比为0.10时,Ni催化剂团聚现象严重,难以生成碳纳米管;提出了碳洋葱、竹节碳和碳纳米管不同碳纳米结构可能的形成机理。     

α-MnO2纳米线的微波法制备及其电化学性能研究

以KMnO₄为锰源,在离子液体1-丁基-3甲基咪唑六氟磷酸盐[BMIM][PF₆]水溶液中通过微波加热法制备了α-MnO₂纳米线,并采用XRD和FESEM对产物的结构和形貌进行了表征。发现反应时间和离子液体对产物的形貌和尺寸起着关键作用,提出了反应机理。用循环伏安曲线、线性扫描曲线以及塔弗尔曲线在1mol/L的NaOH碱性溶液中研究了α-MnO₂的电化学性能。结果表明,90℃微波辐照1h所得到的纳米线形貌最均一,平均直径为15nm、平均长度为2μm,且具有良好的电化学性能,有望作为催化剂应用在燃料电池上。     

Ag glasses based on Zn-phosphate

The partial substitution of Zn²⁺ for Ag⁺ in Ag₄P₂O₇ leads to the formation of a wide glassy domain of composition [Ag₄P₂O₇] _(1−y) [Zn₂P₂O₇] _(y) with 0.20y0.87. The introduction of AgI in these materials results in a new series of glasses of formula [(Ag₄P₂O₇)_(1−y) (Zn₂P₂O₇)_(y)] _(1−X) [AgI] _(x), which domain for the composition y = 0.25 corresponds to 0x 0.64. The structure as well as the thermal and electrical properties of these materials are compared with those of the [AgPO₃] _(1−X) [AgI] _(x) and [Ag₄P₂O₇] _(1−x) [AgI] _(x) glasses.