魔芋葡甘聚糖的H2O2氧化改性及其流变性能研究

用过氧化氢（H2O2）对魔芋葡甘聚糖进行氧化改性，探讨了不同料液比、PH值、温度、H2O2加入量及反应时间对氧化反应的影响，得到最佳的反应条件为：料液比为1：4、PH为7．5、反应温度为45℃，H2O2加入量为2．4％，反应时间为4h；改性魔芋葡甘聚糖水溶胶非牛顿行为显著降低，溶胶粘度稳定性及酸碱稳定性大幅提高。     

新型纳米V_2O_5催化剂的制备与表征

以片状工业V2O5晶体为原料,采用Sol-gel法制备含纳米V2O5颗粒的溶胶和凝胶,并以此胶体为活性组分、硅藻土为载体制得一种新型纳米钒催化剂,研究了催化剂的显微结构和性能。结果表明,经过酸洗处理后的硅藻土的物理化学性质满足催化剂载体要求,TEM和SEM研究显示,胶体中V2O5颗粒形貌呈现针状或球状,催化剂中的活性组分V2O5颗粒大小仍然处于纳米级别且分散均匀,纳米钒催化剂的强度为61.3N.cm-1,活性达87.4%。     

Sol-Gel法二氧化硅溶胶的制备及性能影响研究

以正硅酸乙酯为前驱体,硝酸为催化剂,制备了SiO2溶胶.研究了催化剂、水、乙醇的加入量对溶胶粘度和凝胶时间的影响。结果表明,在保持其它反应条件不变的情况下,随着EtOH/TEOS摩尔比的增大,溶胶粘度减小,凝胶时间变长;随着H2O/TEOS摩尔比的增大,溶胶粘度先增大后减小,凝胶时间先变短后变长,H2O/TEOS=9.6左右时粘度最大,凝胶时间最短;pH<2时,随着HNO3/TEOS摩尔比的增大,溶胶粘度增大,凝胶时间变短。     

制备参数对纳米V2O5颗粒形貌的影响

用透射电子显微镜、微观体视学图象分析系统研究冶金V2O5溶胶中V2O5颗粒的微观形貌，以及制备工艺参数对其微观形貌的影响。结果表明；V2O5颗粒形貌呈现出多样性，既有针状，又有近球状和球状，还有“短棒状”和“椭球状”；近球状V2O5颗粒非常接近于球状；V2O5颗粒的团聚方式也呈现多样性，且团聚时效较快。随着水的体积与冶金五氧化二钒质量之比[简称水钒比，V(w)／m(V)]的降低，V2O5颗粒形状由针状、近球状逐渐过渡到球状。当V(w)／m(V)在40mL／g以下时，颗粒基本上呈球状。熔化温度升高，则V2O5颗粒直径增大。恒温时间延长则V2O5颗粒直径减小。     

CTAB辅助电沉积V_2O_5薄膜及储锂性能研究

以五氧化二钒、双氧水和十六烷基三甲基溴化铵(CTAB)为原料,采用溶胶凝胶法制备了V2O5溶胶,并通过电沉积法在不锈钢基体上制备了正交晶系的V2O5薄膜电极材料。采用X-射线衍射和场发射扫描电子显微镜表征了V2O5薄膜材料的微观结构和表面形貌;采用循环伏安曲线、交流阻抗谱和充放电测试研究了V2O5薄膜作为锂离子电池正极材料的储锂性能。结果表明,在添加3%CTAB的V2O5溶胶中电沉积的V2O5薄膜比未添加CTAB的V2O5溶胶中电沉积的V2O5薄膜具有更高的电化学反应可逆性、更低的电化学反应阻抗、更好的嵌锂活性和倍率性能。     

Ti(OC4H9)4水解过程的粘度控制

报道了用溶胶-凝胶法制备二氧化钛薄膜过程中钛酸丁酯[Ti(OC4H9)4]水解特性的研究结果，给出了体系的酸碱度(酸催化或者碱催化)、添加乙酰丙酮(AcAc)和硝酸银(AgNO3)对Ti(OC4H9)4-C2H5OH-H2O体系粘度变化和凝胶化时间的影响，发现AgNO3对该体系溶胶有非常明显的稳定作用.     

SiO2-Al2O3复合体系溶胶-凝胶转变过程的动力学研究

本文以硅酸乙酯和无机铝盐为前驱体，红外光谱以及热分析等测试手段研究了复合溶胶的溶胶述结果从化学键、电荷密度等方面进行了解释。通过水解法制备SiO2-Al2O3复合溶胶。通过粘度测量、凝胶转变过程及对应凝胶热分解过程中的动力学，并对上     

纳米CaSiO3填料的制备及其性能表征

以乙醇为溶剂，正硅酸乙酯（TEOS）为胶溶剂，CaCO3为主要试剂，采用溶胶-凝胶（Sol-Gel）技术制备纳米偏硅酸钙（CaSiO3）填料，考察主要工艺参数——初始水凝胶pH值、R值（H2O/TEOS）对粉体形貌、颗粒大小等性质的影响。研究表明：采用溶胶-凝胶法能合成纳米级的CaSiO3填料。     

二氧化锡纳米粉体的制备及表征

本文以廉价的SnCl4·5H2O为母盐,分别以NH3·H2O为沉淀剂,采用溶胶—凝胶法和以CO(NH2)2为沉淀剂,利用微波水热法制备SnO2纳米粉体。利用X-射线衍射(XRD),傅里叶变换红外光谱(FT-IR),透射电镜(TEM)技术对产物进行表征。结果表明：溶胶—凝胶法制备的SnO2粉体颗粒约为80nm但颗粒大小分...     

纳米TiO_2复合载体催化剂的制备及表征

采用溶胶 凝胶法分别在γ Al2O3和ZRP 5分子筛上负载纳米TiO2制得复合载体,通过不同的方法在载体上负载纳米V2O5,运用XRD、TEM、IR等对催化剂进行了表征。结果表明:TiO2在载体上分散良好,粒子颗粒均匀,粒径大小在25～35nm之间,TiO2在ZRP 5上粒径比在γ Al2O3小,且Ti Al、Ti Si间存在相互作用,有利于产生新的性能。V2O5粒径大小在8～9nm。     

Phase equilibrium studies in V2O5-Fe2O3 and V2O5-TiO2 systems

V₂O₅-Fe₂O₃ and V₂O₅-TiO₂ systems represent two important chemical systems with various applications, including energy, catalysts, and high-performance materials. In the present study, high-temperature phase equilibrium experiments were conducted at the temperature range of 670–1000°C in air. Electron probe X-ray micro-analyzer (EPMA) was used to analyze the microstructure and composition of the phases presented in quenched samples. Systematic experiments demonstrated that V₂O₅-containing systems should not be quenched by water-based quenching media. Phase diagrams in both systems were constructed, and the eutectic and peritectic points of the systems were confirmed and compared with previous studies. The present study improved the previous results and could be used as the base for thermodynamic modelings and further applications of the two systems.     

V2O5负载量对V2O5／TiO2催化剂SCR法脱硝的影响

以TiO2载体,采用浸渍法制备了不同V2O5负载量的用于选择性催化还原NOx的V2O5／TiO2催化剂。利用BET,SEM和Ⅺ①,对不同V2O5负载量的催化剂组成、结构、形貌和性能进行了表征,考察不同V2O5负载量对催化剂制备的影响。结果表明制备的催化剂具有较多的中孔和微孔,催化剂中V2O5含量的增加,会降低催化剂的表面积;V2O5含量为2％的V2O5／TiO2催化剂样品比表面积最大,但是其活性非常低;V2O5含量为4％催化剂比表面积较大,NOx脱转化率高;V2O5的负载量小时,V2O5主要以等轴聚合的钒基型式（V3O7和V6O13）存在,这些钒基是催化剂的活性中心;当负载量超过6％,V2O5主要以结晶相存在,占据大量活性位,降低催化效果。     

Hot corrosion behavior of NdYbZr2O7 exposed to V2O5 and Na2SO4 + V2O5 molten salts

In order to evaluate the application prospects of NdYbZr₂O₇ as a novel TBC material, NdYbZr₂O₇ ceramic was synthesized via a solid-state reaction sintering method, and its hot corrosion behavior exposed to V₂O₅ and Na₂SO₄ + V₂O₅ molten salts at 900 °C, 1000 °C, and 1100 °C was comparatively investigated. For the V₂O₅ salt, the primary corrosion products were granular (Nd,Yb)VO₄ as well as cube-like m-ZrO₂. The corrosion layer consisted of two distinct layers, one of which was Zr-rich layer and another was V-rich layer. In the case of Na₂SO₄ + V₂O₅, NaVO₃, as an intermediate product, played an important role in dissolving the NdYbZr₂O₇ ceramic. Herein, the (Nd,Yb)VO₄ exhibited a rod/plate-like morphology, which could be attributed to the synergistic effect of low driving force and low nucleation rate. Since the molten salt infiltration rate was superior to the pore filling rate throughout the hot corrosion, the thickness of corrosion layer increased with the rise of temperature. The hot corrosion mechanisms of NdYbZr₂O₇ ceramic in various molten salts were discussed based on the phase diagram, Lewis acid-base rule and chemical thermodynamics. On this basis, the NdYbZr₂O₇ coating was prepared by atmospheric plasma spray (APS) and it exhibits a higher corrosion resistance compared to YSZ coating.     

Semiconducting properties of cold sintered V2O5 ceramics and Co-sintered V2O5-PEDOT:PSS composites

Recently we established a sintering approach, namely Cold Sintering Process (CSP), to densify ceramics and ceramic-polymer composites at extraordinarily low temperatures. In this work, the microstructures and semiconducting properties of V₂O₅ ceramic and (1-x)V₂O₅-xPEDOT:PSS composites cold sintered at 120 °C were investigated. The electrical conductivity (25 °C), activation energy (25 °C), and Seebeck coefficient (50 °C) of V₂O₅ are 4.8 × 10⁻⁴ S/cm, 0.25 eV, and −990 μV/K, respectively. The conduction mechanism was studied using a hopping model. A reversible metal-insulator transition (MIT) was observed with V₂O₅ samples exposed to a N₂ atmosphere, whereas in a vacuum atmosphere, no obvious MIT could be detected. With the addition of 1–2 Vol% PEDOT:PSS, the electrical conductivity (50 °C) dramatically increases from 10⁻⁴ to 10⁻³ ∼ 10⁻² S/cm, and the Seebeck coefficient (50 °C) shifts from −990 to −(600 ∼ 250) μV/K. All the results indicate that CSP may offer a new processing route for the semiconductor electroceramic development without a compromise to the all-important electrical properties.     

V2O5-O pacified White Enamels

Whiteness and opacity were developed in lead borosilicate enamels by additions of 3 to 8 weight % of V²O⁵. These enamels were characterized by their fusibility, maturing at 1125° to 1200°F. Compositions were adjusted to provide fit and adherence to both glass and aluminum. Normal methods of preparing, applying, and firing were employed. Some of the experimental enamels for glass had marginal resistance to hot alkali solutions. Others appeared to be suitable for general-purpose enamels, for which the chemical requirements are not so stringent. The enamels for aluminum, for which acid and weather resistance are desirable, were rated as having class A acid resistance, according to the classification system of the Porcelain Enamel Institute.     

Influence of V2O5 content on ammoxidation of 3-picoline over V2O5/AlF3 catalysts

V₂O₅/AlF₃ catalysts with V₂O₅ loadings ranging from 2 to 15 wt% were prepared by the conventional wet impregnation method, using nonporous AlF₃·3H₂O sample as the support for impregnating NH₄VO₃. It was found that the catalysts evolve porous structures upon calcination at 723 K. The influence of V₂O₅ content was studied on ammoxidation of 3-picoline on the reduced catalysts. The catalyst with 15 wt% V₂O₅ exhibited the highest selective ammoxidation acitivity towards nicotinonitrile. The XRD and oxygen chemisorption studies revealed that vanadia is in a highly dispersed state in the catalysts.     

V2O5-TeO2-P2O5-Fe2O3系无铅低熔点封接玻璃性能研究

研究确定了V2 O5-TeO2-P2O5玻璃的形成范围,系统地探讨了P2O5/TeO2比及V2 O5对玻璃热膨胀系数、特征温度和耐水稳定性的影响规律,结果表明所涉及玻璃组成的耐水性低.对P2O5/TeO2/V2O5比为17.1/20.9/62,外掺Fe2O3玻璃的研究表明,Fe2O3掺入(0mol％～16mo1％),水侵蚀后质量损失由20.05％降低到1.73％,显著提高玻璃耐水稳定性,热膨胀系数由11.5×10-6/℃降低到8.9×10-6/℃,特征温度提高,其中转变温度Tg从267℃升高到310℃,膨胀软化温度Td从284℃升高到330℃.SEM分析发现,掺入Fe2O3玻璃的表面形成明显的未被侵蚀的网状结构,玻璃表面的Hench侵蚀机理由V类转变为Ⅱ类侵蚀机理.     

Thermal Decomposition of Divanadium Pentoxide V2O5: Towards a Nanocrystalline V2O3 Phase

Thermal decomposition of V₂O₅ was studied by means of transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). Samples were heated in a specimen chamber of an electron microscope up to 600 °C in vacuum at 10^-7 Torr. TEM and EELS reveal a sequence of transformations from V₂O₅ via VO₂ to V₂O₃, which differs from the electron-beam-induced reduction of V₂O₅. The phase transformation does not proceed topotactically. Our observation reveals that the initial thermal decomposition of V₂O₅ to V₂O₃ is followed by a combination of diffusion, coalescence, and stabilization processes. Our experiments open a new way for the preparation of single-crystalline V₂O₃ nano-particles.