中孔材料在酸催化反应中的应用

随着M41S系列材料成功合成,中孔材料在催化领域的应用备受关注。中孔材料不仅可以作为酸、碱或氧化还原催化反应的催化剂,且由于内表面存在大量硅羟基,可稳定地与有机物或有机金属复合物的基团相结合,还可以作为高分散度的金属或氧化物的载体。对中孔材料在烷基化和裂化两类酸催化反应中的一些重要应用进行分析,指出中孔材料在新催化体系中的应用以制备具有晶体孔壁的、均一的和可调变中孔孔道的中孔材料为发展方向,同时设法降低合成费用,克服在新催化领域的应用障碍。     

具有特殊形貌的介孔氧化硅的合成及其应用研究进展

具有特殊形貌的介孔氧化硅不仅具有比表面积高、孔径均一可调、形貌多样可控等优点,而且其特殊的介孔结构赋予了材料特殊的用途;不仅是制备高性能催化剂和药物分子的理想载体,而且在吸附分离、金属防腐以及光电磁领域有良好的应用前景。本文介绍了近年来特殊形貌介孔氧化硅材料的合成研究,这些材料包括纳米花状介孔氧化硅、新型球状介孔氧化硅、带状介孔氧化硅、立方体介孔氧化硅等,以及这些特殊结构的介孔氧化硅材料作为载体或前体在催化及药物控释等领域特殊应用的研究进展。指出特殊形貌的介孔氧化硅在电池和能源等方向的研究应用将是今后的研究热点。     

介孔炭氧化改性及金属改性研究进展

介孔炭材料由于它本身的优越结构及性能,自合成以来就受到人们的广泛关注.本文综述了国内外对介孔炭材料进行氧化改性处理包括含氧酸氧化改性、过氧化化合物改性、金属盐氧化改性以及金属改性处理的最新研究成果,经过改性的介孔炭具有更高效的吸附、导电、催化等性能,但目前进行氧化改性条件的研究并不成熟,金属改性的应用同样需要进一步探究.     

介孔碳材料及其负载金属催化剂的制备及应用研究进展

介孔碳材料具有较高比表面积、均一可控纳米孔分布和可调节的表面化学性能,在催化领域具有重要应用前景.综述了介孔碳材料及其负载金属催化剂的制备方法及催化应用进展.     

石墨烯材料在催化剂中应用功能综述

石墨烯和其衍生物(氧化石墨烯、还原氧化石墨烯和掺杂石墨烯等)以独特的物理性质和可调变的表面化学性质在催化领域有巨大的应用潜力。首先简述石墨烯及其衍生物的制备方法和材料特性,接着归纳该材料在催化剂开发与应用中的研究情况,重点阐述石墨烯材料在催化剂中若干功能,包括作为载体负载金属/金属氧化物活性组分或嫁接有机官能团,作为结构助剂调变催化剂微结构,作为电子助剂调变活性组分电子特性,增强半导体材料的光催化功能,在催化剂的制备和分离过程中发挥可调变的两亲性作用,以及直接用作碳催化剂或无金属催化剂,并对石墨烯材料在催化领域的发展前景进行展望。     

金属有机框架化合物应用于催化反应研究进展

金属有机框架化合物(Metal-organic frameworks,MOFs)是一种新型有机骨架材料,具有高的表面积和孔隙率,而且多孔框架结构丰富、可控性强,在催化领域具有较大的应用潜力。综述了MOFs催化剂具有的结构特点,并根据MOFs材料的催化方式总结了其在催化方面的相关应用,探讨了MOFs在实际催化应用中的性能优势及可能存在的问题,并对MOFs材料在催化领域中的应用前景做了展望。     

炭催化甲烷裂解制氢研究进展

综述了炭催化甲烷裂解制氢的研究进展,重点阐述了具有不同孔结构特征的微孔炭、介孔炭和金属负载型炭催化剂在甲烷催化裂解制氢过程中的催化性能和影响规律。与微孔炭具有较高初始活性、较低稳定性相比,介孔炭或具有微孔/介孔结构的多级孔结构炭材料表现出更高的催化活性和寿命;将金属负载于炭材料制得的金属负载型催化剂可同时利用金属的高活性和炭材料相对较高的稳定性提高催化裂解甲烷性能。该文还对炭催化甲烷裂解机理进行概述,指出通过调控炭材料结构与组成、提高甲烷催化裂解性能和加强对炭催化甲烷裂解机理研究是今后发展的方向。     

异丙苯催化氧化催化剂研究进展

异丙苯氧化反应是石油化学工业中重要的反应过程,传统的异丙苯氧化工艺是以少量的氧化产物过氧化氢异丙苯作为引发剂的无催化氧化工艺,存在效率低和安全性差等缺陷。几十年来,研究者对异丙苯催化氧化工艺进行了广泛研究,开发的催化剂类型主要有碱金属或碱土金属催化剂、金属氧化催化剂、过渡金属离子有机络合物催化剂、N-羟基邻苯二甲酰亚胺类催化剂、负载型催化剂、金属及合金催化剂和中孔分子筛催化剂等。其中,改性MgO催化剂、Ag及Ag-Au合金催化剂和负载过渡金属杂原子的中孔分子筛催化剂表现出较优越的催化性能,具有较好的开发前景。但迄今为止报道的各类催化体系还不能彻底解决传统氧化工艺的固有问题,开发具有高活性、高选择性和高稳定性的环境友好催化体系是今后研究的重点。     

希夫碱金属配合物作为催化剂的应用

简要介绍了近几年来希夫碱及其金属配合物作为催化剂在催化氧化反应,烯烃的聚合、环丙烷化以及环氧化反应中的研究进展。     

光催化氧化芳香醇制芳香醛的研究进展

芳香醛是一类重要的精细化工中间体,常被用于药物、香料等的合成。传统的生产工艺采用氧化法或氯化水解法,其缺点是能耗高,环境污染严重。光催化氧化作为一种绿色的合成技术日益受到人们的关注,传统的半导体材料在光催化氧化芳香醇制芳香醛的反应中选择性差,可见光利用率低。因此,发展新型可见光催化材料是实现光催化氧化技术应用的核心。近几年来,金属有机骨架材料(Metal-organic Frameworks,MOFs)的蓬勃发展为研发具有高选择性催化氧化活性的新型光催化材料带来了新的希望。文章重点阐述了不同光催化材料在选择性氧化芳香醇制芳香醛中的研究现状及存在的问题,并对其发展趋势作了展望。     

硫醇转化催化剂及硫醇氧化反应机理研究进展

综述了国内外硫醇转化催化剂及硫醇氧化反应机理的研究概况。介绍了酞菁钴类硫醇转化催化剂、固体碱硫醇转化催化剂以及硫醇的碱催化氧化反应机理和氧化还原催化氧化反应机理。指出以新型硫醇转化催化剂取代目前工业上的酞菁钴类催化剂势在必行。     

Catalytic Oxidation of Alkylaromatics over Mesoporous (Cr)MCM-41

Liquid-phase catalytic oxidation of certain alkylaromatics over mesoporous (Cr)MCM-41 molecular sieves in the presence of chlorobenzene and tertiary butylhydroperoxide showed high substrate conversion and excellent product selectivity. The high catalytic activity of the materials is attributed to the complete oxidation of chromium ions to hexavalent chromium and the absence of pentavalent chromium in the mesoporous matrix.     

丙烷氧化脱氢制丙烯介孔催化材料

介绍了丙烷氧化脱氢制丙烯介孔催化材料的研究进展,包括介孔分子筛和介孔金属氧化物催化剂,综述载体、活性组分和制备方法等对丙烷氧化脱氢催化性能的影响,着重评述提高介孔分子筛催化剂催化活性的方法。     

Nitridation of MgO-loaded MCM-41 and its beneficial applications in base-catalyzed reactions

Nitrogen-containing MgO-MCM-41 solid base material is prepared by nitridation of MgO-loaded mesoporous MCM-41. The ordered mesoporous structure and high surface area of MCM-41 are well preserved after MgO impregnation and nitridation, as proved by the XRD, TEM and nitrogen adsorption/desorption analysis. FTIR spectra the bridging -NH- groups and terminal -NH₂ groups are incorporated into the framework of MgO-MCM-41 by nitridation, and the base strength is expected to be enhanced due to the replacement of oxygen by nitrogen with lower electronegativity. FTIR spectra with the adsorption of different probe molecules, e.g. CO, CD₃CN and ¹³CO₂, are employed for the characterization of surface acidic-basic properties of MgO-MCM-41 before and after nitridation. It is revealed that the acidic hydroxyls in MgO-MCM-41 are greatly reduced through nitridation process. Compared with MgO-MCM-41, the nitridized MgO-MCM-41 material exhibits improved basic catalytic performances in Knoevenagel condensation reaction, Claisen-Schmidt reaction and dehydrogenation reaction of 2-propanol.     

Preparation and catalytic properties of new mesoporous materials

The development of ordered mesoporous solids is revised. Acid, base, and redox catalytic properties are presented together with their application for a series of organic reactions of fundamental and practical interest. Finally it is explained that it is possible to make use of the high surface and regular porosity of MCM–41 to prepare supported metals, and bifunctional catalysts. The above properties together with the presence of a large number of surface silanol groups allow the grafting of catalytically active transition metal complexes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Ordered Mesoporous Materials with Improved Stability and Catalytic Activity

Microporous crystals of zeolites such as Y, Beta, and ZSM-5 are widely used commercial catalysts, but their applications are strongly limited by their small pore sizes. Recent progress in solving this is used to ordered mesoporous materials such as MCM-41, HMS, and SBA-15. These mesoporous materials have pore diameters of 2.0–30 nm and exhibit good catalytic properties for the catalytic conversion of bulky reactants. However, when compared with microporous crystals of zeolites, the catalytic activity and hydrothermal stability are relatively low, which severely hinders their practical applications in industrial catalytic reactions such as petroleum cracking. The relatively low catalytic activity and hydrothermal stability can be attributed to the amorphous nature of the mesoporous walls. In this account, we systemically review the routes for improving catalytic activity and hydrothermal stability of mesoporous materials, which include (1) acidic sulfated zirconia supported in mesoporous materials; (2) strongly acidic and thermally stable mesostructured sulfated zirconia with tetragonal crystalline phase; (3) strongly acidic and hydrothermally stable mesoporous aluminosilicates synthesized in alkaline media; (4) strongly acidic and hydrothermally stable mesoporous aluminosilicates synthesized in strongly acidic media; (5) hydrothermally stable mesoporous titanosilicates with catalytically active titanium species in oxidations; (6) high-temperature generalized synthesis of ultrastable ordered mesoporous silica-based materials by using fluorocarbonhydrocarbon surfactant mixtures.     

提高多产丙烯性能的ZSM-5分子筛改性研究进展

催化裂化装置在多产丙烯方面扮演着重要的角色,ZSM-5分子筛由于具有特殊的孔道结构、活性较高以及择形催化等特点,是催化裂化多产丙烯主要催化剂。综述采用改性手段增强ZSM-5分子筛水热稳定性和引入介孔提高分子可及性研究进展,主要包括F改性,P改性,过渡金属及稀土掺杂等改性手段,以及物理化学法脱铝脱硅,软模板法和硬模板法修饰ZSM-5分子筛孔道。     

Mesoporous Carbon: A Versatile Material for Scientific Applications

Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body’s oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.     

钙钛矿复合氧化物的介孔化及用于CH4催化燃烧

利用有序介孔立方相(Ia3d)乙烯基三乙氧基硅烷(TEVS)为模扳,通过纳米组装法在硅基硬模板的介孔中填入La - Fe -柠檬酸络合物,经焙烧和碱洗去除硅基模板,制备具有有序介孔结构且高比表面积的LaFeO3钙钛矿(ABO3),并与软模板法和自燃烧法制备的LaFeO3钙钛矿催化荆作对比,运用XRD、TEM和BET对合...