堇青石负载Fe-Mn-O混合氧化物催化氧化甲苯的性能研究

采用浸渍法制备了以FeOx和MnOx混合氧化物为活性组分,堇青石蜂窝陶瓷为载体的有机废气催化燃烧催化剂,以甲苯作为探针反应物测定该类催化剂的催化燃烧活性。考察了Fe与Mn物质的量比、焙烧温度及其改性载体等因素对甲苯催化燃烧性能的影响,深入进行了XRD和BET表征与分析。实验结果表明:Fe/Mn物质的量的比为4∶1,质量负载量为10%,焙烧温度为500℃,并经γ-Al2O3涂层改性的催化剂具有最佳的催化燃烧活性。     

堇青石负载Mn-Zn-O复合金属氧化物的甲苯催化燃烧性能

以堇青石蜂窝陶瓷为载体、Mn(NO3)2和Zn(NO3)2为原料,采用过量浸渍法制备负载型Mn-Zn-O复合氧化物催化剂,考察Mn与Zn摩尔比、负载量及焙烧温度对甲苯催化燃烧性能的影响,并采用表面积分析仪(BET)、扫描电镜(SEM)和X线衍射仪(XRD)对催化剂进行表征。结果表明:n(Mn)/n(Zn)为2,负载量为10%,经450℃焙烧的催化剂表现出最佳的甲苯催化燃烧性能,在300℃及体积空速为10 000 h-1条件下,催化燃烧质量浓度为3.8μg/m3的甲苯,催化转化率可达91.4%。     

Cu-Mn复合氧化物催化剂的制备和VOCs催化燃烧性能

以堇青石为载体,制备了堇青石负载Cu-Mn-Ag过渡金属氧化物催化剂.对其进行了甲苯催化燃烧活性评价,并采用TPR技术对催化剂进行了表征研究.探索了制备方法、助剂对催化剂的性能影响.表明Ag的引入有利于提高催化剂的甲苯的催化燃烧性能,而K的引入则抑制了其催化性能.     

Pd/ZSM-5/堇青石整体式催化剂对甲苯的催化降解性能研究

以蜂窝状堇青石为载体,采用聚乙烯醇(PVA)溶液辅助涂覆法制备Pd/ZSM-5/堇青石整体式催化剂,利用XRD、N2吸附-脱附、SEM等方法对催化剂结构和性质进行表征。通过气相色谱分析催化剂对甲苯降解效果,考察了Pd的质量分数、堇青石煅烧时间及浆料涂覆次数对催化降解甲苯性能的影响。结果表明,ZSM-5分子筛具有较大比表面积,能有效负载Pd,在粘结剂的作用下与堇青石载体有效结合;制备的5%Pd/ZSM-5/堇青石对甲苯的催化降解效果最好,T₅₀和T₉₀分别为275℃和313℃;堇青石焙烧时间4 h的催化效果最好;负载5%Pd质量分数的分子筛对堇青石涂覆6次时性能最优,制备的Pd/ZSM-5/堇青石整体式催化剂显示出良好的催化氧化甲苯活性。     

复合氧化物催化剂催化氧化甲苯性能

以γ-Al2O3为催化剂载体,铜、锰为活性组分,稀土元素铈为助催化剂,采用浸渍法制备复合氧化物催化剂5%Cu/γ-Al2O3、5%Mn/γ-Al2O3、5%Cu-5%Mn/γ-Al2O3和5%Cu-5%Mn-1.6%Ce/γ-Al2O3,并考察其催化氧化甲苯性能。研究表明,复合氧化物催化剂催化氧化甲苯具有显著的效果,5%Cu-5%Mn/γ-Al2O3催化剂和5%Cu-5%Mn-1.6%Ce/γ-Al2O3催化剂表现出良好的低温活性和催化性能,对甲苯的完全燃烧温度分别为340℃和285℃。采用SEM和BET对催化剂进行表征,结果表明,催化剂的催化活性与活性组分在催化剂表面的分散度和催化剂的孔结构相关。     

ZSM-5/堇青石整体催化剂对NO低温氧化的催化性能

采用原位水热合成技术,以蜂窝状堇青石陶瓷为载体,分别合成了硅铝比为300的高硅和纯硅的ZSM-5分子筛/堇青石整体催化剂,并采用X射线衍射(XRD)和扫描电镜(SEM)等手段对催化剂进行了表征,考察了反应温度、水汽含量和空速等对NO氧化反应的影响.结果表明:在硅铝比为300的ZSM-5/堇青石和纯硅ZSM-5/堇青石整...     

氧化铈的引入量对堇青石多孔陶瓷的性能影响

实验以煤矸石、滑石和氧化铝为主要原料,以稀土金属氧化物氧化铈(CeO₂)为烧结助剂,将试样分别在1 225、1 250、1 275、1 300℃的温度下保温3 h,主要研究CeO₂的引入量(质量分数)分别为0、1%、2%、3%、4%时,试样基本物理性能和物相组成的变化规律。结果表明：当试样在1 300℃的烧成温度下保温3 h,CeO₂的引入量为2%(质量分数)时,试样的体积密度为0.87 g·cm^-3,显气孔率为68.58%,吸水率为78.68%,且通过XRD表征试样中堇青石相的纯度较高,说明以煤矸石为主要原料、CeO₂为烧结助剂可在较低温度下合成具有一定基础性能的堇青石多孔陶瓷,为堇青石的低温合成技术和煤矸石的综合利用奠定一定的理论基础。     

氧化锆增韧堇青石陶瓷的研究

添加分散的氧化锆对多晶体堇青石进行了增强和增韧。含１０％（按质量计，下同）ＺｒＯ２的氧化锆增韧堇青石陶瓷（ＺＴＣＣ）的抗弯强度（１３０ＭＰａ）较１４００℃，６ｈ制备的人工合成高纯多晶堇青石的（７４．３ＭＰａ）有明显提高。含有５％ＺｒＯ２和１％ＣａＯ二元弥散相粒子的ＺＴＣＣ的断裂韧性增大至２．８３ＭＰａ·ｍ＾１／２。当加入１５％Ｙ－ＴＺＰ，样品的抗弯强度和断裂韧性分别高达１８８ＭＰａ和３．２ＭＰａ·     

海城绿泥石合成堇青石的研究

利用海城绿泥石作为合成堇青石的主要原料.试验表明:用绿泥石合成堇青石其合成温度低,合成温度范围宽,合成堇青石的热膨胀系数达1.8×lO~-6/℃(22～800℃),膨胀曲线直线性好.与海城滑石作为合成堇青石原料相比,具有明显的优越性,为开发和应用海城绿泥石创造了条件.     

负载型金属氧化物催化剂对交叉氧化偶联反应的催化作用

采用甲烷和甲苯作为催化交叉氧化偶联的评价反应,考察了Al2O3、MgO、CaO、TiO2及其负载碱金属催化剂。在不同碱金属含量、不同反应条件下进行了活性和选择性的研究,并提出了交叉氧化偶联的可能机理。     

混合金属氧化物固载杂多酸催化合成顺丁烯二酸二丁酯

用微波合成法制备了含钛钨混合金属氧化物的固载多酸催化剂HPA/TiO2-WO3,用IR,TEM等对催化剂进行了表征。新催化剂在顺丁烯二酸二丁酯的合成反应中显示很好的活性和温和的反应条件。当顺丁烯二酸0．1mol,正丁醇0．3mol,催化剂0．7g(占总反应物料的2％),反应温度100～110℃,反应时间45min时,顺丁烯二酸二丁酯的产率可达97．6％。     

Mechanical Activation of Perovskite-Type Oxides for Catalytic Combustion

The effect of grinding on the catalytic properties of La_0.8Sr_0.2MnO_3± powders prepared via a ceramic or sol–gel process was studied with respect to the carbon black combustion temperature (T ^C). For the ceramic process, a milling time of 5 h led to a decrease of 77°C in the T ^C (from 615 to 538°C) in relation with increasing BET surface area. Regarding the sol–gel process, the T ^C decreased from 535 to 505°C after 1 h of grinding. Nevertheless, upon further milling (10 h), the benefit of the grinding effect disappeared due to a continuous decrease in the BET surface area. Finally, grinding (when well controlled) enabled one to obtain ceramic powders showing performances as good as sol–gel materials (T ^C540°C).     

助催化剂对甲苯歧化与烷基转移催化剂性能的影响

采用助催化剂对丝光沸石进行改性,通过红外光谱（FT—IR）方法表征了该改性分子筛制备的催化剂样品表面酸性的变化,并探讨了酸性变化对甲苯歧化与烷基转移反应催化活性的影响。结果表明,助催化剂WO3的加入能有效地调节催化剂表面酸性,经氢气还原后催化剂B酸量随助催化剂量增加而增加,且与助催化剂相对含量呈对数关系;而L酸量随助催化剂相对含量的增加先上升,随后趋于平稳;催化剂的反应活性随助催化剂含量的增加而增加,但副反应也随之加大。     

甲苯二氨基甲酸甲酯催化分解反应的研究

对甲苯二氨基甲酸甲酯（TDC）热分解制备甲苯二异氰酸酯（TDI）进行了研究,考察了溶剂、温度、压力、催化剂浓度及热载体和催化剂重复利用对TDC液相分解性能的影响。最佳反应条件为：邻苯二甲酸二辛酯（DOP）为溶剂,反应温度260℃,反应压力5.4 kPa,冷凝柱顶温度165℃,TDI的最高收率为99%;邻苯二甲酸二辛酯、...     

Catalytic Activity of Supported Platinum and Metal Oxide Catalysts for Toluene Oxidation

Oxidation of toluene has been investigated over supported platinum as well as over a variety metal oxide (M _x O _y ) catalysts dispersed on high surface area γ-Al₂O₃. Catalysts were characterized with respect to their specific surface area (BET), metal dispersion (selective chemisorption of CO), phase composition and M _x O _y crystallite size (XRD) and reducibility (H₂-TPR). Catalytic performance for the title reaction was investigated in the temperature range of 100–500 °C, using a feed composition consisting of 0.1% toluene in air. For Pt/M _x O _y catalysts, it has been found that catalytic performance depends on the nature of the support, with Pt/CeO₂ being the most active catalyst at low temperatures. The intrinsic reaction rate per surface platinum atom does not depend on Pt loading (0.5–5 wt%), at least for Pt/Al₂O₃. Reducible metal oxides, such as ceria, are active for the title reaction and catalytic performance is improved significantly with increase of specific surface area (SSA). However, the intrinsic reaction rate per unit surface area is invariant with SSA. Dispersion of M _x O _y on high surface area inert supports, such as Al₂O₃, results in materials with relatively high catalytic activity, which seems to correlate well with the reducibility of metal oxides. Catalytic performance of M _x O _y /Al₂O₃ catalysts can be optimized by proper selection of M _x O _y loading. Best performing catalysts of this series include 60% MnO, 90% CeO₂ and 5% CuO on Al₂O₃ which, under the present experimental conditions, are able to completely convert toluene toward CO₂ at temperatures lower than 350 °C. Dispersion of Pt on M _x O _y /Al₂O₃ catalysts improves significantly the catalytic performance of irreducible M _x O _y but does not alter appreciably the activity of reducible M _x O _y /Al₂O₃ catalysts.     

金属担载分子筛对含硫模型化合物和含硫烃的催化裂化脱硫反应的影响

Zn, La, Zr, Sn and Ti loaded molecular sieves were prepared by impregnation method. Conversions of benzothiophene and dibenzothiophene over the metal oxides modified ultra stable zeolite Y(USY), ZSM-5, β and MSU-2 molecular sieve catalysts were investigated by means of micro-activity test (MAT) experiments. The results showed that Zn and La loaded catalysts were better than the other metals, and ZSM-5 with lower SiO2/Al2O3 mole ratio showed better results than those with higher SiO2/Al2O3 as far as desulfurization reaction is considered. A comparison of the desulfurization activities of the La/Zn-USY catalyst with USY catalyst indicated that the bimetal loaded USY catalyst gave good products selectivity when sulfur containing heavy oil was used as the feedstock. The sulfur content in gasoline fraction was decreased by 25%, and there was no loss in the Research Octane Number.     

二氧化锰/石墨烯臭氧催化氧化甲苯反应性能

采用一步水热合成法,在180℃,12 h条件下制备了30%二氧化锰/石墨烯(MnO2/G)复合材料。实验结果表明:MnO2均匀且较为牢固地锚定于石墨烯表面,同时MnO2的沉积阻止了多层石墨烯的复合,从而使得复合物具有较大的比表面积。相同条件下,MnO2/石墨烯相较于单纯MnO2或石墨烯具有很好的臭氧催化氧化甲苯性能,这可以归结于MnO2和石墨烯间的协同催化作用。     

相对湿度对不同载体的负载Cu催化剂催化燃烧甲苯的影响

The copper based catalysts, CuO/γ-Al2O3, CuO/γ-Al2O3-cordierite (Cord) and CuO/Cord, were prepared by impregnation method. The catalytic activity of the catalysts was tested in absence and presence of water vapor, and the catalysts were characterized. Temperature program desorption (TPD) experiments of toluene and water on the catalysts were carried out. The influence of water vapor on the activity of the catalysts was discussed. Results showed that addition of the water vapor has a significant negative effect on the catalytic activity of the catalysts. The higher the concentration of the water vapor in feed steam was, the lower the catalytic activity of the copper based catalysts became, which could be mainly ascribed to the competition of water molecules with toluene molecules for adsorption on the catalyst surfaces. TPD experiments showed that the strength of the interaction between water mole-cules and three catalysts followed the order: CuO/γ-Al2O3>CuO/γ-Al2O3-Cord>CuO/Cord. As a consequence of that, the degree of degradation in the catalytic activity of these three catalysts by the water vapor followed the order: CuO/γ-Al2O3>CuO/γ-Al2O3-Cord>CuO/Cord. However, the negative effect of the water vapor was reversible.