改性MCM-41负载铁基催化剂的制备及其催化降解亚甲基蓝的研究

以自制二元共聚物聚[苯乙烯—3-(甲基丙烯酰氧)丙基三甲氧基硅烷]改性MCM-41,并以其为载体制备铁基非均相催化剂。研究了该催化剂对亚甲基蓝的催化降解性能,同时利用FT-IR、XRD、SEM、NH3-TPD、氮气等温吸附(BET)等手段分析了分子筛改性后对铁基催化性能的影响。结果表明,改性MCM-41负载铁基催化剂具有优异的催化降解亚甲基蓝性能,25 min时去除率达到81.2%,与纯MCM-41负载铁基催化剂相比,性能提高了33.9%。     

介孔CuCo/FeCeOx催化剂协同催化类Fenton反应

类Fenton反应是降解水中有机污染物的有效方法之一，开发高效的非均相催化剂至关重要。通过硬模板法制备了Fe掺杂的具有有序介孔结构的FeCeO_x材料，以此为载体通过浸渍法负载Cu和Co后，构建了具有多金属活性位点的催化剂。催化剂在亚甲基蓝降解反应中表现出优异的催化性能，在45 min内可将亚甲基蓝完全降解，且具有良好的循环使用性能，使用5次后亚甲基蓝降解率仍达到93.3%。催化剂的介孔结构有利于吸附亚甲基蓝，暴露更多的活性位点，多金属之间的协同作用促进了催化剂上的电子转移，从而提高H₂O₂的活化效率和促进·OH的产生。     

PW/MCM-41光催化性能研究

以浸渍法制备了负载型光催化剂PW/MCM-41,并对催化剂进行了表征,考察了催化剂在光催化模拟染料废水亚甲基蓝(MB)溶液降解反应中的催化活性.实验结果表明:催化剂负载量为30％、催化剂投加质量浓度为3.0g/L、MB溶液的初始质量浓度为10 mg/L、pH=5、光照时间100 min时,对亚甲基蓝降解率可达91％以上...     

改性凹凸棒土负载铜和稀土催化氧化印染废水

随着服装行业的迅速发展,纺织工业中印染废水的总量与日俱增,对人类的健康造成严重的威胁。本文采用浸渍法制备负载铁和镧的改性凹凸棒土当作催化剂,以臭氧为氧化剂催化氧化含亚甲基蓝的印染废水,考察了不同催化剂用量、反应温度、亚甲基蓝初始浓度以及臭氧流量对亚甲基蓝降解率的影响。结果表明：当改性凹凸棒土用量为0.3g、臭氧流量为100mL/min、搅拌转速为500r/min、反应温度为45℃、反应时间为30min时,50mg/L亚甲基蓝废水的降解率就达到了96%左右;改性凹凸棒土表征结果表明Fe³⁺、La³⁺活性组分已经负载在凹凸棒土上,且负载效果较好。     

环己烷催化氧化制环己酮的MCM-41催化剂研究

以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,采用水热合成法制备纯MCM-41分子筛和掺杂不同金属离子的MCM-41分子筛,并采用等体积浸渍法将一定量的金属离子负载在纯MCM-41分子筛内表面上,制备了负载型和掺杂型2类不同的MCM-41分子筛催化剂.分别考察了负载和掺杂的金属种类、金属Cr负载和掺杂量等对环己烷氧化制环己酮中的催化活性和选择性的影响.研究表明:采用掺杂制备的MCM-41分子筛催化剂活性明显高于负载型MCM-41分子筛催化剂;Cr掺杂量增加,虽然环己烷氧化转化率增加,但产物选择性下降;掺杂Cr的MCM-41分子筛催化剂,用于环己烷氧化制环己酮,在Si与Cr摩尔比为50以下、反应温度75℃、H2O2与环己烷摩尔比为1.2的条件下,环己烷的转化率可达60%左右,环己酮和环己醇的总选择性可达94%以上.     

金属酞菁催化氧化含硫化合物的实验研究

采用浸渍法将1,4,8,11,15,18,22,25-(异戊氧基)酞菁钴(铜,镍)分别负载到介孔分子筛MCM-41上,形成MCM-41-Co Pc,MCM-41-Ni Pc,MCM-41-Cu Pc组装体。在(20±1)℃,p H=7氧气气氛下,以各组装体为催化剂,研究了其对Na2SO3溶液的催化氧化活性。实验结果表明:各组装体具有良好的催化氧化性能,不同金属酞菁组装体表现出不同的催化活性,MCM-41-Co Pc催化剂的催化氧化性能最好。同种催化剂在不同浓度Na2SO3溶液中的催化活性也有所不同,此类催化剂可重复利用5次。负载型金属酞菁对硫化物的催化氧化作用,可以应用到油气田开发中的污水处理方面,对环保贡献了一定力量。     

负载型ZrOx/MCM-41分子筛催化α,β-不饱和醛的MPV还原反应的研究

采用Zr（NO3）4为Zr源,水为溶剂,浸渍法制备了负载型ZrOx/MCM-41介孔分子筛催化剂,考察了其在以异丙醇为氢源,苯甲醛为模型反应物,经氢转移法还原为苯甲醇的反应（MPV反应）中的催化性能,同时对样品进行XRD、N2吸附-脱附、IR、UV等表征分析,并与水合ZrO2、骨架掺杂Zr-MCM-41进行对比研究。结果表明：ZrOx/MCM-41分子筛性能最为优异,负载范围为2.5%～20%时,Zr负载量对性能影响较不明显,最佳负载量为5%;焙烧温度对性能影响较明显,最佳焙烧温度是300℃,以300℃焙烧8h的5%ZrOx/MCM-41分子筛为催化剂,在76℃、反应8h后,苯甲醛的转化率为88%,苯甲醇的选择性〉99%。该类催化剂具有较好的抗水性、抗活性组分流失性和再生性能。ZrO2负载于MCM-41上时可能形成表面Si-O-Zr-OH基团,其可能是该催化剂性能优异的主要原因,催化剂表面少量存在的NO3^-可能增加了其酸性,使其活性进一步提高。     

活性炭纤维负载TiO2薄膜的制备及对亚甲基蓝的光催化降解

采用浸渍-水解法,制备了活性炭纤维(ACF)负载TiO2薄膜。通过XRD、SEM与XPS对膜进行了表征,并研究了该负载型催化剂对亚甲基蓝的光催化降解性能。结果表明,所得薄膜为锐钛矿晶型,在其循环使用过程中,经140 m in光催化反应对亚甲基蓝的去除率始终维持在99.8%~99.9%,说明该产品对亚甲基蓝具有高的光催化活性和重复利用性。在有无紫外光照两种情况下,通过比较所制备催化剂在5次循环使用中对亚甲基蓝的去除性能,以及降解产物中铵离子的浓度变化,证明亚甲基蓝的去除是被TiO2降解而不是被ACF吸附。     

MCM-41负载氧化铜活性组分的结构及其氢程序升温还原特性

用浸渍、表面改性、掺杂、离子交换等方法制备了CuO负载的MCM-41(CuO-MCM-41)催化剂。用X射线衍射、高分辨电镜、氢程序升温还原等技术研究了CuO在MCM-41上的分散情况及氧物种的反应特性。结果表明：负载在MCM-41上的CuO的还原温度要比纯CuO的降低200℃。用离子交换法比浸渍法、掺杂法制备的样品中CuO的分散程度更高，具有更高的氧活性。在有序孔道内分散的高活性的CuO可望在催化领域得到应用。     

Co-Zr/MCM-41催化氧化石蜡的研究

从催化氧化石蜡生产特种蜡及其添加剂的角度出发,采用Co/SiO2、Co/MCM-41、Zr/MCM-41、Co-Zr/MCM-41为催化剂,用空气作氧化剂,对石蜡氧化进行了实验研究。考察了金属负载量对催化性能的影响、不同负载金属催化剂的石蜡氧化活性比较、Co、Zr含量对Co-Zr/MCM-41活性的影响。实验结果表明,以MCM-41作为载体制备钴负载量为12%、锆负载量为3%的复合氧化物为催化氧化反应的催化剂,在氧化温度为140℃、氧化时间为5 h、空气流量为0.7 L/min、催化剂用量为2%的最经济反应条件下可得到高酯酸比的氧化蜡产品。     

载体结构对钙钛矿氨分解催化活性的影响

采用溶胶凝胶法,制备了负载型镍基钙钛矿型催化剂,并在常压微反应装置上对其氨分解催化活性进行了评价。采用BET、XRD、TPR、TEM等方法对催化剂进行表征。研究结果表明,以MCM-41分子筛为载体的催化剂,由于其较大的比表面积和规整的介孔结构,使活性组分能够很好地分散在载体表面,有利于增加有效活性位,提高活性组分的反应能力,表现出很好的氨分解催化活性。以NiO计,负载量为20%的LaNiO₃/MCM-41具有比非负载的LaNiO₃更好的催化活性,这样不仅提高了催化活性,还大大地减少了活性组分用量,降低了生产成本,从而具有很好的应用前景。     

Ag-BiVO4／MCM-41制备表征及光催化性能研究

采用浸渍法将Ag-BiVO4固载于MCM-41介孔分子筛上,制备了Ag-BiVOdMCM-41新型复合可见光催化荆,用IR、XRD、SEM等分析测试手段对其进行了结构和性能表征。分析表明：Ag-BiVO4光催化剂为单斜耜结构,复合光催化剂具有较大的比表面积。在λ〉400nm的可见光照射下,以降解亚甲基蓝溶液进行了光催化剂的光催化性能评价。实验结果表明,Ag—BiVO4/MCM-41具有高的可见光催化活性,且具备良好的吸附性能和高的光催化效率。     

基于MCM-41的镍基甲烷化催化剂活性与稳定性

采用浸渍法分别以MCM-41,Al₂O₃和SiO₂ 为载体制备了不同镍负载量的甲烷化催化剂,并在连续流动固定床反应装置上对其甲烷化催化活性进行了评价。研究结果表明,与Ni/Al₂O₃和Ni/SiO₂相比,相同镍负载量的Ni/MCM-41催化剂具有更好的催化活性。同时研究了Ni含量对于Ni/MCM-41催化剂催化活性的影响,发现随着Ni含量的增加,CO转化率和CH₄收率逐渐升高,并且在Ni含量大于10%（质量分数）以后趋于稳定。在n（H₂）：n（CO）=3：1、反应压力1.5 MPa、反应温度350℃及质量空速12000 ml·h^-1·g^-1的反应条件下,10%Ni/MCM-41催化剂CH₄选择性达到94.9%,CO转化率接近100%。在100 h催化活性稳定性试验中,10%Ni/MCM-41催化活性无明显下降,表现出良好的催化活性稳定性。采用X射线衍射（XRD）、氮气物理吸附（BET）、热重分析（TG）及氢气程序升温还原（H₂-TPR）等技术手段对催化剂进行了表征,结果表明Ni颗粒大小是影响Ni/MCM-41催化剂催化活性的主要因素。     

Ni-Mo双金属催化剂的甲烷化性能与耐硫稳定性

采用沉淀-浸渍法合成一系列Ni-Mo基双金属催化剂,在固定床反应器中对其催化活性和耐硫性能进行评价,并辅以不同的表征手段阐释其作用机理。实验结果表明,以MCM-41分子筛为载体的催化剂活性和稳定性优于以NaY、γ-Al₂O₃和拟薄水铝石（PB）为载体的催化剂;反应前后催化剂的表征结果则说明Ni-Mo分子间适宜的相互作用是决定催化剂性能的关键。MCM-41载体催化剂中适宜的Ni-Mo分子间相互作用使得此催化剂中活性组分与载体间的相互作用适中,还原后的活性金属Ni能够均匀分散在载体表面,从而提高了催化剂的耐硫稳定性和抗积炭能力。不同Ni-Mo比同样会影响Ni-Mo分子间的相互作用,通过考察确定20Ni-10Mo/MCM-41的活性和稳定性最优。     

Preparation of sulfated alumina supported on mesoporous MCM-41 silica and its application in esterification

New types of mesoporous SA/MCM-41 solid acid catalysts were prepared by loading sulfated alumina (SA) on MCM-41. The prepared catalysts were characterized by XRD, IR, N₂ physisorption, elemental analysis, FT-IR of adsorbed pyridine and NH₃-TPD. The esterification of acetic acid with n-butanol and citric acid with n-butanol were used as model reactions to test the catalytic activities and reusability of the SA/MCM-41 solid acid catalysts. Compared with SA catalyst, SA/MCM-41 catalysts exhibited higher catalytic performances, which were attributed to their high BET surface area and large pore volume. Moreover, 20SA/MCM-41 solid acid catalyst showed excellent reusability in both esterifications.     

Well-Dispersed Gallium-Promoted Sulfated Zirconia on Mesoporous MCM-41 Silica

Gallium-promoted sulfated zirconia (SZ) was confined inside pure-silica MCM-41 (abbreviated as SZGa/MCM-41), where the latter served as a host material. It was prepared by direct dispersion of metal sulfate in the as-synthesized MCM-41 materials, followed by thermal decomposition. The SZGa/MCM-41 catalysts were characterized by XRD, N₂ adsorption, HRTEM, DRIFT, NH₃-TPD, and TPR. The experimental results showed that the ordered porous host structure was still maintained in the catalyst. SZ was in meta-stable tetragonal phase and highly dispersed on the interior surface of MCM-41 even at a high loading of 50 wt%. Additionally, a small fraction of SZ nanoparticles on the external surface of MCM-41 was obtained. The catalytic activity of SZGa/MCM-41 was examined in n-butane isomerization. In comparison to SZ/MCM-41 without promoter, the catalytic activities of the Ga-promoted catalysts were greatly improved. The reason proposed for the higher activity of the Ga-promoted catalysts was that Ga enhances the oxidizing ability of the catalysts.     

Synthesis and investigation of anchored copper (II) complexes within MCM-41 as selective catalysts for epoxidation of olefins

In the present study, preparation, characterization and catalytic activity of encapsulated copper (II) complexes within MCM-41 were investigated. The mesoporous molecular sieve MCM-41 was synthesized and grafted with 3-(trimethoxysilyl)-1-propanethiol to give a thiol modified material (MCM-41-S). The prepared material successively was reacted with acrylic acid and acrylonitrile to give AA-MCM-41 and AN-MCM-41, respectively. Using hexamethyldisilazane and copper (II) chloride, copper (II) complexes in the cavities of MCM-41 (Cu-AA-MCM-41 and Cu-AN-MCM-41) were prepared. The presence of copper (II) complex on the surfaces of host matrix and the structure of prepared catalyst is investigated by FT-IR, inductively coupled plasma-optical emission spectroscopy (ICP-OES), powder X-ray diffraction (XRD) and BET nitrogen adsorption–desorption methods. The catalytic activities of the catalysts were studied in epoxidation of olefins. The results showed that activities of the prepared catalysts (Cu-AA-MCM-41 and Cu-AN-MCM-41) and their selectivity to corresponding epoxides were more than those of MCM-41. In addition, the synthesized heterogeneous catalysts were truly reusable.     

Well-dispersed Ceria-promoted Sulfated Zirconia Supported on Mesoporous Silica

Ceria-promoted sulfated zirconia (CeSZ) was supported on mesoporous molecular sieve of pure-silica MCM-41 (abbreviated as CeSZ/MCM-41). It was prepared by direct impregnation of metal sulfate onto the as-synthesized MCM-41, followed by solid state dispersion and thermal decomposition. The resultant catalysts were characterized by TG, XRD, nitrogen physisorption and TEM. It was showed that the hollow tubular structure of MCM-41 was retained, even with ZrO₂ loading as high as 60 wt.%. Most of CeSZ was well dispersed on the interior surface of the ordered mesopores, following a slight twist of the channels. The catalytic activity of CeSZ/MCM-41 was studied in the octadecanol oxidation. The improved performance of CeO₂-promoted catalysts was attributed to the high dispersion of sulfated zirconia (SZ) and the introduction of CeO₂ enhancing the oxidation ability of catalysts by retarding the transformation of zirconia from highly catalytic active metastable tetragonal phase to monoclinic phase.     

Sn修饰SBA-15、MCM-41催化剂的制备及顺酐酯化性能

以SBA-15和MCM-41分子筛为载体,负载无水四氯化锡,制备了SnCl4-SBA-15和SnCl4-MCM-41催化剂,考察了不同锡与硅物质的量比对催化顺酐与正丁醇酯化反应的影响。结果表明,SnCl4-SBA-15表现出比SnCl4-MCM-41更高的催化性能,顺酐转化率为99.8%,副产物较少,马来酸二丁酯的产率最高可达91.3%。采用X射线衍射、N₂物理吸附、傅立叶红外光谱和紫外-可见漫反射技术对催化剂进行表征,结果显示, SnCl₄-SBA-15具有较高的比表面积,较大的孔容和孔径,更有利于催化反应的进行。