含铜三元类水滑石化合物的合成及其性质

 以Cu（NO3）2，Zn（NO3）2和Al（NO3）3为原料，以NaOH为沉淀剂，利用共沉淀法合成了含铜三元类水滑石化合物CuZnAl－HTLcs．从不同Cu／Zn／Al比的混合原料溶液的滴定曲线入手，详细探讨了溶液pH值、原料加入方式、组分配比及水热处理条件对类水滑石合成的影响，利用XRD，ICP及比表面积测定对合成物进行了表征，并以苯酚羟基化为探针反应评价了催化剂的催化性能．结果表明，在体系pH＝5．0～6．2，（Cu＋Zn）／Al摩尔比＝2．0，Cu／Zn摩尔比≤1．0及室温条件下共沉淀后，于100℃水热处理3h，即可得到晶相单一和结晶度高的CuZnAl－HTLcs．变化pH法合成的样品的相对结晶度为100％，低过饱和法为76．5％，高过饱和法为75．9％．合成的CuZnAl－HTLcs中Cu2＋的含量均比原料液中Cu2＋的含量有所增加，这可能是由于在pH＝5．8时Cu2＋对Al（OH）3的同晶取代能力比Zn2＋强．随着CuZnAl－HTLcs中Cu含量的增加，催化剂对苯酚羟化反应的催化活性逐渐增大．     

Cu－HMS分子筛的合成条件及其催化性能

 以十二胺（DDA）为模板剂，正硅酸乙酯（TEOS）为硅源，在中性介质中于室温条件下合成了含Cu的中孔杂原子分子筛Cu－HMS．在85℃及常压下，以异丙苯氧化（O2为氧化剂）为探针反应考察了Cu源、Cu／Si摩尔比、DDA／TEOS摩尔比和晶化时间等合成条件对分子筛催化氧化性能的影响．实验结果发现，在Cu／Si摩尔比为0．02～0．03，DDA／TEOS摩尔比为0．1～0．3，晶化时间为1h以上，Cu源为Cu（NO3）2的条件下得到的Cu－HMS分子筛催化活性最高．用XRD，29SiMASNMR，FT－IR，低温N2吸附和原子发射光谱（ICP）等手段对催化活性最高的分子筛样品的结构及表面性质进行了表征，证明该分子筛具有典型的HMS结构，同时发现Cu元素已进入分子筛骨架结构．     

用CuO／γ－Al2O3催化剂同时脱除烟气中的SO2和NO

 研究了用CuO／γ－Al2O3催化剂同时脱除烟气中的SO2和NO，并在固定床反应器中考察了反应条件对其催化活性的影响．结果表明，温度和SO2对CuO／γ－Al2O3的催化活性均具有双重影响．新鲜催化剂和硫化催化剂上最适宜的脱硝温度分别为250～300℃和300～450℃，最适宜的n（NH3）／n（NO）约为1．2．烟气中的氧可大大提高CuO／γ－Al2O3的脱硫脱硝活性．综合考虑吸附硫容和NO脱除率，CuO／γ－Al2O3同时脱硫脱硝的最适宜温度为350～450℃．温度和SO2在高温区对CuO／γ－Al2O3活性的影响源于两者对NH3氧化活性的改变，高温下CuO／γ－Al2O3的活性下降是因为NH3氧化加剧；SO2通过使催化剂硫化生成硫酸盐来抑制NH3氧化，从而提高CuO／γ－Al2O3的活性．吸硫饱和的催化剂可于5％NH3中还原再生，再生后其硫容较初始时降低，但其活性大幅度提高．     

氧化铝对Fe－Cu－Zn－K－Al低碳醇合成催化剂性能的影响

 采用N2吸咐，TPR和XRD等表征手段对高温熔融法制备的Fe－Cu－Zn－K－Al催化剂中氧化铝的作用进行了研究．结果表明，当比表面积低于4．0m2／g时，催化剂性能受比表面积的影响非常明显．少量的Al2O3即可有效地增加催化剂的比表面积，提高醇的收率和C2＋OH的选择性；大量的Al2O3虽然能使催化剂的比表面积有所增加，但醇的收率和C2＋OH选择性却显著降低．这是Fe－Cu－Zn－K－Al催化剂中Al2O3同时具有物理作用和化学作用所致．物理作用能有效地增加还原后催化剂的比表面积，提高金属利用率，分散催化剂的活性组分，使其更容易还原，进而提高催化剂活性和选择性．化学作用影响到催化剂的电子性质，从而导致催化剂的活性和选择性降低．TPR和XRD结果表明，在Fe－Cu－Zn－K－Al催化剂中，助剂Al2O3的作用随着其含量的变化而有所不同．当Al2O3含量较低时，其物理作用是主要的；随着Al2O3含量的增加，其化学作用更为明显，甚至导致新物相AlFeO3生成，进而影响催化剂的催化性能．     

不同Si/Al比对Mo/ZSM-5催化性能的影响

采用浸渍法在不同Si／Al比的HZSM-5上制备了3种MoO3含量相同的Mo／ZSM-5样品，并在相同的实验条件下对其进行了活性测试，同时运用XRD、XPS、NO—TPD等技术分别对催化剂的体相和表面结构进行了表征．实验结果表明，Si／Al比对Mo／ZSM-5上NO的选择性催化还原性能有明显的影响，Si／Al比为28的1#样品其转化率在530℃达到94％以上，而Si／Al比较大的2#和3#样品最高转化率只有48％和41％．对3种Mo／ZSM-5样品的XRD表征只发现有HZSM-5和MoO3两种物相存在，分子筛骨架差异不大；而XPS表征却发现1#样品的表面M03d5／2含量远大于2#和3#样品，并且有Mo^4 和(或)Mo＼ 5 存在，表明3种样品的表面性质存在很大差异．在3种样品中，1#样品具有最大的NO吸附能力，这与表面特性差异相吻合．     

Cu/ZnO/Al2O3催化剂上1,4-丁二醇脱氢合成γ-丁内酯

 研究了顺酐加氢催化剂Cu／ZnO／Al2O3在常压下对1,4－丁二醇脱氢合成γ－丁内酯的催化活性．结果表明,Cu／ZnO／Al2O3催化剂不但具有良好的顺酐加氢活性,而且在较温和的反应条件下对于1,4－丁二醇脱氢同样具有良好的催化活性,γ－丁内酯的收率可达95％以上．通过XRD和AES测试发现,Cu0为催化剂的脱氢活性中心,ZnO的存在有利于Cu0在载体表面的高度分散,并对脱氢活性有促进作用,在还原态的催化剂中ZnO被部分还原为ZnOx（x≤1）,并与Cu0形成Cu0／ZnOx,构成最佳活性单元．     

红外光谱研究Pt-Re/Al2O3重整催化剂的表面结构

CO和NO吸附或两者竞争吸附在Pt／Al2O3，Re／Al2O3和Pt－Re／Al2O3催化剂上的红外光谱可以给出Pt和Re的表面结构信息．本文研究的催化剂为低金属载量的Pt／Al2O3，Re／Al2O3和工业型Pt－Re／Al2O3，其中Pt含量0．22％，Re含量0．43％（质量分数）．实验结果表明，用NO与CO双分子竞争吸附的红外光谱实验方法可分别表征还原态Pt－Re／Al2O3重整催化剂上Pt表面和Re表面，并视需要可对Pt表面和Re表面进行半定量分析．在还原态工业型Pt－Re／Al2O3重整催化剂表面上，没有明显迹象表明有Pt－Re合金形成．     

NO在Au／Al2O3催化剂上还原反应的TPD-MS研究

 考察了沉积－沉淀法制备的Au／Al2O3催化剂在O2存在下催化C3H6还原NO的反应，并用程序升温脱附－质谱（TPD－MS）手段研究了吸附于催化剂上的NO或NO－O2的脱附性能．结果表明：在O2存在的条件下，对于C3H6还原NO的反应，1％Au／Al2O3的催化活性最高，可于375℃左右使NO生成N2，转化率达60％．这与催化剂对所吸附NO的脱附性能密切相关，N2O可能是C3H6还原NO反应过程中产生的比较稳定的中间体．     

富氧条件下氮氧化物的选择性催化还原Ⅰ．Ag／Al2O3催化剂上C3H6选择性催化还原NO的性能

 利用自行研制的全自动催化剂活性评价装置和原位漫反射红外光谱仪，分别考察了Ag的负载量和形态、氧浓度及水蒸气添加对Ag／Al2O3催化剂上C3H6选择性催化还原NO性能的影响．结果表明，Ag的最佳负载量为4％～6％，此时粒径为15nm左右的银簇粒子均匀地分散在Al2O3载体表面．在GHSV＝50000h－1和θ＝430～550℃条件下，4％Ag／Al2O3上NO转化率可达90％以上．反应过程中有机含氮化合物及NO2的生成，导致NO和NOx转化率间产生差异．当氧浓度为7％时，催化剂对NO选择性还原的催化活性最高．水的添加阻碍了活性中间物种NCO及其前驱体的形成，导致催化剂的平均活性下降．     

Pd－Cu／γ－Al2O3催化还原硝酸盐的研究

 地下水中硝酸盐的污染已引起人们普遍的关注，催化还原硝酸盐技术被认为是一项有发展前景的脱除硝酸盐工艺．利用Pd－Cu／γ－Al2O3悬浮态催化剂和管状陶瓷催化膜，在间歇式完全混合反应器中对脱除地下水中硝酸盐进行了研究，考察了催化剂、硝酸盐初始浓度、H2流量对还原反应的影响．结果表明，Pd－Cu／γ－Al2O3可有效地脱除硝酸盐，总氮的脱除率可达81％；同时，催化剂的活性和选择性受到扩散限制和质量传输的影响．与悬浮态催化剂相比，管状陶瓷催化膜可提供固－液－气三相之间有效的接触，在很大程度上提高了催化反应的选择性，对氮的选择性由73．4％提高到89．4％．这是一项有效、实用的催化还原技术，尤其适用于小型水厂以及没有统一供水系统而是自家开采地下水作为饮用水源的农村地区．     

Cu交换度对贫燃条件下 Cu-Al-MCM-41上NO选择性催化还原的影响

利用程序升温反应技术考察了cu交换度对Cu-Al-MCM-41上NO选择性还原反应性能的影响,同时结合XRD,N2吸附等温线,NMR,ICP-AES,TPD和TPR等技术对催化剂的结构特征和化学吸附性能进行了表征．结果表明,经Cu离子交换的Al-MCM-41并未改变载体的结构特征,仍保持长程有序的中孔结构．影响Cu-Al-MCM-41催化剂选择性还原活性的主要因素是Cu交换度,而不是Cu含量,前者决定了活性中心(主要是Cu^2 )的浓度．当Cu交换度低于100％时,随着Cu交换度的增加,NO最大转化率增加．当交换度超过100％后,催化剂的还原活性下降,此时出现的CuO起完全氧化的催化作用而非选择性还原的催化作用．在n(Si)／n(Al)=10,Cu交换度接近100％的Cu-Al-MCM-41上360℃时可获得79％的NO最大转化率．     

Synthesis,Characterization and Catalysis of Ce‐MCM‐41

The cerium‐containing MCM‐41 (Ce‐MCM‐41) has been synthesized by direct hydrothermal method. The low‐angle XRD patterns revealed the typical five major peaks of MCM‐41 type hexagonal structures. The interplanar spacing d₁₀₀ = 38.4 Å was obtained that can be indexed on a hexagonal unit cell parameter with a_o = 44.3 Å which was larger than that of pure siliceous MCM‐41 (Si‐MCM‐41). Transmission electron micrograph shows the regular hexagonal array of uniform channel characteristics of MCM‐41. The BET surface area of Ce‐MCM‐41 was 840 m²/g, which is much reduced as compared to that of Si‐MCM‐41, with the pore size of 26.9 Å and mesopore volume of 0.78 cm³/g were measured by nitrogen adsorption‐desorption isotherm at 77 K. Along with the results, the synthesized Ce‐MCM‐41 exhibited a well‐ordered MCM‐41‐type mesoporous structure with the incorporation of cerium. Using Ce‐MCM‐41 as a support, the Rh (0.5 wt%) catalyst exhibited very high activity for the NO/CO reactions.     

Ti—MCM—41的结构特征与芳烃羟化反应的化学亲和选择性

以不同硅源合成了Si/Ti比不同的Si-Ti－MCM－41,并在引入Ti的同时引入Al,合成了Si/Al比不同的Si-Ti-Al-MCM-41。XRD、TEM、低温N2吸附的表征结果说明,Ti-MCM-41具有长程有序一维孔道,且比表面积较高,FT－IR光谱表征说明,Ti对骨架Si的取代使MCM－41表面出现缺陷羟基。Al的引入有利于Ti-MCM-41有序结构的形成。且可调变Ti-MCM-41的表面性质。Ti-MCM-41在不同极性芳烃化合物的羟化过程中表现出化学亲和选择性,且调变Ti-MCM-41的表面性质可实现对化学亲和选择性的控制。     

Synthesis of binaphthols over mesoporous molecular sieves

Mesoporous aluminosilicates (Al-containing NaMCM-41) were applied as catalyst supports for oxidative coupling of β-naphthol and substituted β-naphthols due to their remarkable features such as surface area, ordered mesopores and high thermal stability. The NaMCM-41 supported copper catalysts prepared by impregnation method, and Cu-NaMCM-41 was prepared by incorporating copper during synthesis. Oxidative coupling of β-naphthol reaction was studied using molecular oxygen as oxidant. The copper supported NaMCM-41 catalysts were prepared with different Si/Al ratios and calcined from 120 to 420 °C were observed to show varied product selectivity. The NaMCM-41 supported copper catalysts and Cu-NaMCM-41 were more active than the corresponding Cu/Fe supported on NaY zeolite. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), UV–DRS, ICPMS and BET surface area techniques and the reaction products were confirmed by ¹H-NMR, FTIR and HRMS. An attempt has been made to explain the product selectivity of the catalysts discussed with the above techniques. The high dispersion of Cu⁺² species observed in the catalysts having high Si/Al ratios in NaMCM-41 support and catalysts that are calcined at low temperatures, i.e. less than 420 °C, yielded an unexpected product perylene diol. A comparatively low dispersion of Cu⁺² species, noticed in catalysts having low Si/Al ratios and calcined at high temperatures, yielded binapthol as the coupled product. The effect of the variation of catalyst and the solvent are also studied.     

The Stability of Monolith CuZSM-5 Catalysts for the Selective Reduction of Nitrogen Oxides with Hydrocarbons: I. Synthesis and Characterization of Bulk CuZSM-5 Catalysts

The effects of ion-exchange conditions (the pH, the copper concentration in solution, and the solution-to-zeolite volume ratio) and the Si/Al atomic ratio of HZSM-5 zeolite on the concentration and state of copper in bulk CuZSM-5 catalysts and on the catalytic activity in the selective reduction of NO with propane were studied. It was found that the concentration and state of copper in the catalysts essentially depend on the pH of the solution used for ion exchange and on the copper concentration in this solution. An increase in the solution-to-zeolite volume ratio has almost no effect on the above characteristics. Regardless of the Si/Al atomic ratio of zeolite and of the pH of solution, a maximum activity (NO conversion) of the resulting catalyst is attained even at an exchange level (Cu/Al) close to 100% (80–140%). The absolute value of this catalytic activity depends only on the reaction temperature and is equal to 22–31% at 300°C or 85–97% at 400–500°C. The above exchange level is maximally attainable at pH 6 in the chosen range of copper acetate concentrations in solution (2–10 mg/ml accounted as CuO). An increase in the pH of ion exchange up to 100% allows a wider variation in the exchange level and the state of copper in the zeolite with the same range of copper concentration in the solution. However, at Cu/Al 100% (up to 430%), the catalyst activity is independent of the exchange level. The state of copper in freshly prepared samples affects the stability of the catalysts in storage. In turn, the state of copper depends on ion-exchange conditions and the Cu/Al ratio.     

分散法制备的CuCl/MCM-41上C3H6选择催化还原NO反应的研究

研究了由分散法制备的两种CuCl/MCM-41催化剂上丙烯在过量氧存在下选择催化还原NO反应, 发现所制备的CuCl/AlMCM-41催化剂的反应活性明显高于CuCl/SiMCM-41. XRD, IR, TPR及ESR的研究结果表明, CuCl/AlMCM-41催化剂上的主要活性中心是与骨架铝配位的铜离子(Cu2+/Cu+).     

Specific activity of copper species in decomposition of NO on Cu-ZSM-5

The kinetids of NO decomposition to N₂ over Cu-ion exchanged ZSM-5 with different Si/Al ratios and the change of the specific activity per copper site as a function of the Cu/Al ratio suggest that the copper species formed at a Cu/Al ratio of 0.5 or higher and probably containing extra-lattice oxygen have higher turnover frequency in the reaction.     

Surface characterization and catalytic evaluation of copper-promoted Al-MCM-41 toward hydroxylation of phenol

The Mobil Composition of Matter No. 41 (MCM-41) containing Cu and Al with Si/Al ratios varying from 100 to 10 and 1 to 6 wt.% of Cu was synthesized under hydrothermal and impregnation conditions, respectively. The samples were characterized by nitrogen adsorption–desorption measurements, X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD), and ²⁹Si and ²⁷Al magic-angle spinning–nuclear magnetic resonance (MAS–NMR) spectra. X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. TPR patterns show the two-step reduction of Cu species. TPD study shows that Cu-impregnated Al-MCM-41 samples are more acidic than Al-MCM-41. From the MAS–NMR it was confirmed that most of the Al atoms are present tetrahedrally within the framework and some are present octahedrally in extraframework position. Impregnation of Cu shifted Al to the extraframework position. The catalytic activity of the samples toward hydroxylation of phenol in aqueous medium was evaluated using H₂O₂ as the oxidant at 80 °C. The effects of reaction parameters such as temperature, catalyst amount, amount of H₂O₂, and solvent were also investigated. Sample containing 4 wt.% copper-loaded Al-MCM-41-100 showed high phenol conversion (78%) with 68% catechol and 32% hydroquinone selectivity.     

Ketone Hydrogenation by Using ZnO−Cu(OH)Cl/MCM‐41 with a Splash of Water: An Environmentally Benign Approach

MCM‐41‐supported ZnO?Cu(OH)Cl nanoparticles were synthesized via an incipient wetness impregnation technique using zinc chloride and copper chloride salts as well as water at room temperature. The catalyst was characterized by powder X‐ray diffraction (PXRD), infrared spectroscopy (IR), and TGA, whereas surface and morphological studies were performed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The above studies revealed the incorporation of metal species into the pores of MCM‐41, leading to a decrease in surface area of the nanoparticles that was found to be 239.079 m²/g. The substituents attached to the ketone determine the rate of the reaction, and the utilization of the green solvent ‘water’ astonishingly completes the hydrogenation reaction in 45 minutes at 40 °C with 100% conversion and 100% selectivity as analyzed by gas chromatography‐mass spectrometry. Hence, ZnO?Cu(OH)Cl/MCM‐41 nanoparticles with 2.46 wt% zinc and 6.39 wt% copper were demonstrated as an active catalyst for the reduction of ketones without using any gaseous hydrogen source making it highly efficient as well as environmentally and economically benign.     

Correlation between the Cu/Al Value and Activity of Cu-ZSM-5 Catalysts and the Chemical Nature of the Starting Copper Salt

Cu-ZSM-5 catalysts for the selective reduction of NO with propane were obtained by ion exchange between H-ZSM-5 zeolite and an aqueous or aqueous ammonia solution of a copper salt (acetate or nitrate). Their Cu/Al values (%) defined as 2 × 100 (Cu : Al), where Cu : Al is the copper-to-aluminum atomic ratio, were determined as a function of ion exchange pH, which was varied by changing the copper salt and solution concentration. Cu/Al is primarily determined by the chemical nature of the starting copper salt. For a given salt, it is governed by the salt concentration in the solution. At a fixed salt concentration, Cu/Al is always larger for copper acetate than for copper nitrate. It can be raised to ≫100% by using an aqueous ammonia solution of a copper salt. Furthermore, it increases with increasing Si/Al in the starting zeolite if the other ion exchange conditions are equal. Irrespective of preparation conditions, the catalytic activity of Cu-ZSM-5 grows in proportion to Cu/Al. It peaks at Cu/Al ∼ 100% and then remains constant up to Cu/Al ∼ 400%. In order to achieve Cu/Al ∼ 100%, it is most appropriate to use a copper acetate solution.__________Translated from Kinetika i Kataliz, Vol. 46, No. 4, 2005, pp. 652–656.Original Russian Text Copyright © 2005 by Tsikoza, Matus, Ismagilov, Sazonov, Kuznetsov.