Research on the High-Strength Coating Preparation Methodology based on Acid Catalytic and Sol-Gel Method

In this paper, we conduct research on the high-strength coating preparation methodology based on acid catalytic and Sol-Gel method. This method has been widely used in the preparation of various functional thin film, film and protective film structure, etc. As a result of sol gel process continuously broaden the application field, this method has been more and more get the favor of people. Compared with other traditional preparation methods of inorganic material, sol-gel process has many characteristics. To adjust the solution acidity and add a small amount of acid or alkali can have the effect of＂ catalyst, its reaction process on sol to get and gel structure may also be affected. Our research analyze the topic theoretically and numerically which is meaningful.

Effects of sol-gel method and lanthanum addition on catalytic performances of nickel-based catalysts for methane reforming with carbon dioxide

The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction performances of catalysts were investigated with BET, TPR, and TPD. Compared with the catalyst prepared by the impregnation method, the results indicated that the catalysts prepared by the sol-gel method had larger specific surface area, showing higher catalytic activities and exhibiting perfect desorption and reduction performances. In addition, the modification effects of adding La were studied, and it was found that the 0.75NLBT catalyst constituted of 5wt.%Ni-0.75wt.%La was optimal.

Selective catalytic reduction of NO with NH_3 over sol-gel-derived CuO-CeO_2-MnO_x/γ-Al_2O_3 catalysts

Granular CuO-CeO2-MnOx/γ-Al2O3 catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO2-MnOx/γ-Al2O3 catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. Preliminary tests were carried out to analyze the behavior of NH3 and NO over catalyst in the presence of oxygen. The optimum temperature range for SCR over the CuO-CeO2-MnOx/γ-Al2O3 catalysts is 300-400 ℃ . The catalysts maintain nearly 100% NO conversion at 350 ℃. The NH3 oxidation experiments show that both NO and N2O are produced gradually with the increase of temperature. The catalysts in this experiment have a stronger oxidation property on NH3, which improves the denitrification activity at low temperature. The over-oxidation of NH3 at high temperature is the main cause leading to a decrease in the NO conversion. The NH3 and NO desorption experiments show that NH3 and NO can be adsorbed on CuO-CeO2-MnOx/γ-Al2O3 granular catalysts. The transient response of NH3 and NO indicates that the SCR reaction proceeds in accordance with the Eley-Rideal mechanism. The adsorbed NO has little influence on the denitrification activity in SCR process.

Synthesis of CaCu_3Ti_4O_(12)powders and ceramics by sol-gel method using decanedioic acid and its dielectric properties

The CaCu3Ti4O12 xerogels, powders and ceramics were prepared through the sol-gel method using two kinds of organic acid （decanoic acid and decanedioic acid）. The xerogels, powders and ceramics were characterized by the methods of TG-DTG, FT-IR, XRD, SEM and TEM. The dielectric properties of the ceramics were also measured. The results indicated that the powders calcined at 850 ℃ for 2 h are both nanometer scale particles. After sintering, the ceramics mainly consist of the CaCu3Ti4O12 phase. Compared with the powders prepared using monoacid, the particle size of the powders prepared using diacid obviously increases, and the grain size, the relative density and the whole permittivity of the ceramics increase as well. Specially, the ceramic prepared using decanedioic acid has higher relative density （97.3%）, dielectric constant （316 808） and lower dielectric loss （0.242 5） at 30 ℃ （10 kIaz）

Catalytic Kinetic Determination of Micro Amounts of Oxalic Acid by Second-Order Derivative Oscillopolarography

It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K 2Cr 2O 7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃ . Orange Ⅳ exhibited a sensitive second order derivative polarographic wave at -0 50 V( vs . SCE). This provides the basis for a sensitive and selective catalytic kinetic method for oxalate determination with second order derivative oscillopolarography. The effects of sulphuric acid, K 2Cr 2O 7, and orange Ⅳ concentrations, reaction temperature and reaction time were investigated. A calibration curve of oxalate in the range of 0 1-2 0 μg/mL was obtained by the fixed time procedure. The detection limit was 0 03 μg/ mL. The possible interference from co existing substances or ions was examined. The new method has a high sensitivity and a good selectivity compared to other existing methods for oxalic acid determination. It has been applied to the determination of micro amounts of oxalate in real urine samples with satisfactory results.

Characterization and CO Catalytic Oxidation of CuO/Ce-Zr-La-O Catalyst

The Ce-Zr-La-O solid solution was prepared by the sol-gel method. Thestructure and the redox behavior of Ce-Zr-La-O solid solution and CuO/Ce-Zr-La-O catalysts wereinvestigated by using XRD, Raman and TPR techniques. The result shows that the reduction capabilityof Ce_(0.7)Zr_(0.3-y)La_yO solid solution is related to content of La. Appropriate content of La canenhance the redox capability of the solid solution. The oxidation activity of the CuO (6 percent)/Ce_(0.7)Zr_(0.15)La_(0.15)O catalyst is the highest. CuO, which finely dispersed and interacted withthe support, is the site of oxidation activity.

Preparation and optical characteristics of ZnO films by chelating sol-gel method

The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absoluteethanol, and citric acid were used as precursor, solvent, and chelating agent, respectively. Theresults show that ZnO films derived from zinc-citrate have lower crystallization temperature (below400℃), and that the crystal structure is wurtzite. The films, treated over 500℃, consist ofnano-particles and show to be porous at 600℃. The particle size of the film increases with theincrease of the annealing temperature. The largest particle size is 60 nm at 600℃. The opticaltransmittances related to the annealing temperatures become 90% higher in the visible range. Thefilm shows a starting absorption at 380 nm, and the optical band-gap of the thin film (fired at500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).

Effects of ultrasonic impregnation combined with calcination in N_2 atmosphere on the property of Co_3O_4/CeO_2 composites for catalytic methane combustion

CoO/CeOcomposites with high surface areas and ultrafine crystalline sizes for catalytic combustion of methane were firstly prepared by a new sol-gel method which combined ultrasonic impregnation treatment and calcination in Natmosphere. The samples were characterized by various means such as nitrogen adsorption/desorption, X-ray diffraction(XRD), Htemperature-programmed reduction(H-TPR),X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). Results showed that the modified catalyst had the mesoporous structure, comparatively higher amount of surface oxygen and larger oxygen vacancies than others. As a result of the structure and surface composition merits, a high methane combustion conversion(50%) could be obtained at a low temperature of 262 °C for the modified CoO/CeOcomposites catalysts. The experimental results demonstrated that ultrasonic impregnation treatment combined with the Nthermal treatment prior to calcination in air had a promising application for preparation of CoO/CeOcomposites catalysts for low-temperature catalytic combustion of methane.

Improved activity of Ni-Mo/SiO_(2) bimetallic catalyst synthesized via sol-gel method for methylcyclohexane cracking

To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.

Preparation and electrochemical performance of Li_2Mn_(0.5)Fe_(0.5)SiO_4 cathode material with sol-gel method for lithium ion batteries

Li2Fe0.5Mn0.5SiO4 material was synthesized by a citric acid-assisted sol-gel method. The influence of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+) on the electrochemical properties of Li2Fe0.5Mn0.5SiO4 was studied. The final sample was identified as Li2Fe0.5Mn0.5SiO4 with a Pmn21 monoclinic structure by X-ray diffraction analysis. The crystal phases components and crystal phase structure of the Li2Fe0.5Mn0.4SiO4 material were improved as the increase of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+). Field-emission scanning electron microscopy verified that the Li2Fe0.5Mn0.5SiO4 particles are agglomerates of Li2Fe0.5Mn0.5SiO4 primary particles with a geometric mean diameter of 220 nm. The Li2Fe0.5Mn0.5SiO4 sample was used as an electrode material for rechargeable lithium ion batteries, and the electrochemical measurements were carried out at room temperature. The Li2Fe0.5Mn0.5SiO4 electrode delivered a first discharge capacity of 230.1 mAh/g at the current density of 10 mA/g in first cycle and about 162 mAh/g after 20 cycles at the current density of 20 mA/g.

无定形硅铝材料的制备及应用研究进展

无定形硅铝(ASA)是由Al_(2)O_(3)和SiO_(2)形成的复合材料,具有较大的孔径、孔体积以及一定的酸性,已在石油加工过程中得到应用。开发高性能的ASA材料对提高催化剂活性、增加目标产品选择性等方面具有重要意义。分析了不同制备方法对ASA材料结构和酸性的影响、ASA材料的酸性成因及其影响因素,综述了ASA材料在加氢裂化、催化裂化和其他催化反应过程中的应用,以期为高性能ASA材料的制备提供指导。结合目前发展趋势提出未来ASA材料研究的主要方向。

不同改性方法对ZSM-5分子筛的影响

ZSM-5分子筛拥有择形性、高水热稳定性、固体强酸性等特点,被广泛应用于催化领域。本研究从ZSM-5分子筛的结构、酸性位点引入,总结了四种用于ZSM-5分子筛改性的方法——水热改性、碱改性、金属改性、非金属改性,分析了各种改性方法的优劣,旨在为开发新的ZSM-5分子筛提供思路。

油脂单塔连续非催化高压逆流水解工艺探讨

天然动植物油脂水解制取的脂肪酸和甘油已成为重要的精细化工原料,简介油脂水解的原理和分类,重点探讨油脂单塔连续非催化高压逆流水解工艺的塔内物料走向、工艺参数、操作控制要点、优缺点及优化建议,为生产应用及工艺改进提供参考。

A new solid acid SO_4^(2-)/TiO_2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate

A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.

1,4-丁二酸市场与生产技术分析

介绍了1,4-丁二酸(SA)的市场、生产技术现状,预测SA未来发展趋势,重点分析了SA几种主要生产技术路线的特点及方向,提出了合理的发展建议。2021年,国外SA总生产能力超过515 kt/a,国内SA总生产能力约119 kt/a,产量约75 kt,进口量约40 kt,消费量约115 kt。SA消费领域主要集中在可降解塑料、食品、医药、农药等领域,其中可降解聚酯消费占比70%以上。已工业化的SA生产工艺主要有催化加氢法、电化学法和生物法,其中催化加氢法加工成本低、工艺流程短;电化学法受原料顺酐价格影响较大,能耗较高;生物发酵法以可再生生物质为原料,符合绿色化工要求,但成本较高、产生废水较多。随着“限塑令”的深入实施,作为可降解聚酯产品的原料,SA将迎来广阔的发展前景,建设液化气-顺酐-SA一体化产业链装置,或者采用符合绿色化工要求的生物发酵法生产SA将具有更好的发展潜力。

Sol-Gel Synthesis Using Novel Chelating Agent and Electrochemical Characterization of Binary Doped LiMn2O4 Spinel as Cathode Material for Lithium Rechargeable Batteries

LiMn2O4 and LiCuxCryMn2-x-yO4 (x = 0.50;y = 0.05 - 0.50) powders have been synthesized via sol-gel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn2O4 and LiCuxCryMn2-x-yO4 confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn2O4 and LiCu0.5Cr0.05Mn1.45O4 authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn2O4 samples calcined at 850℃ deliver the high discharge capacity of 130 mA·h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu0.5Cr0.05Mn1.45O4 delivers 124 mA·h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA·h/g cycle over the investigated 10 cycles.

Pd/CeO_(2)对2,4-二氯苯氧乙酸的液相催化加氢脱氯

采用NaBH4还原法分别制备了不同载体CeO_(2)、活性炭(AC)和石英砂(SiO_(2))的负载型Pd基催化剂。采用Zeta电位、X射线衍射、透射电子显微镜等手段对催化剂进行表征,并利用高活性Pd/CeO_(2)催化剂对2,4-二氯苯氧乙酸(2,4-D)进行液相加氢脱氯反应研究。研究结果表明:载体对催化剂活性影响较大,其中Pd/CeO_(2)催化剂具有高等电点、较强的金属-载体相互作用以及Pd颗粒高分散度的活性特征;Pd/CeO_(2)催化剂对2,4-D的脱氯效果随Pd负载量增加而增加,随pH值的增加呈现先升高后降低的趋势;Pd/CeO_(2)催化剂对2,4-D的加氢脱氯反应符合Langumir-Hinshelwood模型,表明2,4-D在催化剂表面的吸附是反应的速率控制步骤,且Pd/CeO_(2)对不同的污染物都表现出较高的液相加氢还原活性。

超声提取-抗坏血酸还原-催化光度法测定土壤中的碘

建立超声提取-抗坏血酸还原-催化光度法测定土壤中碘含量的方法。将碳酸钠和氧化锌研磨后过孔径为0.25 mm筛,按质量比为3∶2混合均匀,制成艾斯卡试剂。将土壤样品与艾斯卡试剂半熔后用超声提取试样中的碘,分取上清液依次加入抗坏血酸和乙酸,使氧化态的碘和碘单质全部变为碘离子,最后加入4,4'-四甲基二氨基苯甲烷、氯胺T,用分光光度计测定。该方法碘元素的质量浓度在0.0025~0.08 mg/L范围内与吸光度具有良好的线性关系,相关系数为0.9995,检出限为0.25 mg/kg。采用所建方法对土壤样品进行6次平行测定,测定结果的相对标准偏差为3.50%~9.40%;对国家标准物质GBW 07409、GBW 07408a、GBW 07407a 3种标准物质进行测定,测定值均在标准值范围内,相对误差分别为3.41%、0.63%、1.05%。该方法适合于大批量土壤样品中碘的测定。

硫掺杂对纳米TiO_2的结构相变及可见光催化活性的影响

采用酸催化溶胶凝胶法合成硫掺杂纳米TiO2光催化剂。可见光光催化降解亚甲基蓝实验结果表明:当硫脲与钛酸丁酯摩尔比为3.50时,催化剂经500℃热处理后表现出最佳的可见光光催化降解效果。TEM、XRD和Raman光谱等表征结果表明:硫掺杂大大提高了纳米TiO2晶粒的分散程度,有利于制备均一分散的纳米晶粒;另外,硫掺杂有效地抑制了纳米TiO2在热处理过程中由锐钛矿向金红石的转变,一部分硫进入TiO2的晶格取代部分Ti4+而导致一定程度畸变,产生氧缺位,从而大大提高催化剂的可见光催化活性。

配合物催化法合成高纯甘油单硬脂酸酯

采用硼酸络合甘油做催化剂制备甘油单硬脂酸酯。试验了酯化反应时间、反应温度、物料比对产物的影响．甘油单硬脂酸酯含量达到98．5％，总产率为87．3％。