锶磁性固体酸S2O82-/ZrO2SrFe12O19催化剂的制备和表征

以具有优异磁学特性的锶铁氧体(SrFe₁₂O₁₉)粒子为磁性基体, 负载固体酸制备锶磁性固体酸催化剂S₂O₈^2-/ZrO₂-SrFe₁₂O₁₉。利用XRD、 比表面积测试(BET)、 振动样品磁强计(VSM)、 IR等表征手段, 研究了磁性催化剂的表面性质和催化性能。结果表明: SrFe₁₂O₁₉的掺入提高了介稳的四方晶型t-ZrO₂的热稳定性; 固体酸的磁性能较好, 饱和磁化强度(M_s)在30.0 emu·g^-1左右, 矫顽力(H_c)大于3900 G, 有利于磁分离和重复使用; BET表面积为16.0 m²·g^-1, 平均孔径为8.16 nm, 属于介孔磁性材料; 以乌桕油与甲醇的酯交换为探针反应的研究表明, 该固体酸能在较短时间内有效发挥催化作用。     

磁性离子液体的制备与应用研究进展

磁性离子液体是一种新型的功能化离子液体材料,具有优良的热稳定性、优异的电化学性能、良好的溶解性能以及可回收性等特性,使其在萃取分离、反应催化和复合材料等领域具有较好的应用前景。对目前合成的磁性离子液体做了概述并根据构效关系对主要的磁性离子液体进行了分类。综述了磁性离子液体的主要制备方法,主要有一步合成法、二步合成法和辅助合成法。介绍了磁性离子液体在萃取分离、反应催化及碳纳米管复合材料领域应用研究进展。最后根据磁性离子液体在合成和应用中的不足做了展望。     

锶铁氧体负载磁性酸催化剂的制备和性能研究

首次以具有优异磁学特性的锶铁氧体（Sr-Fe12O19）粒子为磁性基体,负载硫酸制备磁性催化剂SO42-/SrFe12O19。利用XRD、BET、VSM等表征手段,结合催化合成产物的表征,研究了磁性催化剂的表面性质和催化性能。结果表明制备出的SO42-/SrFe12O19的饱和磁化强度较大,易于分离。催化合成酯的研究发现催化剂重复使用6次,其作用下的酯化率仍达74%,表现出良好的回收效果。     

磁性纳米粒子的制备及在生物医学领域中的应用概述

磁性纳米材料由于具有优异的纳米效应和磁性能,在生物医药领域可广泛应用于磁靶向、磁热疗、药物递送、生物分离等方面,并已作为核磁共振造影剂应用于临床。通过将不同类型的聚合物基质与磁性纳米填料结合在一起,可开发出多种类型的磁性纳米复合功能材料。文中综述了磁性纳米粒子领域的最新动态,详细阐述了磁性纳米粒子的制备方法和改性技术,讨论了磁性纳米粒子复合材料在药物载体、核磁共振成像、磁热疗等生物医学领域的应用前景。     

影响磁性氧化铁纳米颗粒磁热疗加热效率的因素

磁性纳米颗粒作为产热介质在生物医学方面取得了广泛的应用前景.近年来,新开发的纳米颗粒细胞内疗法更是克服了常规治疗方法的副作用,使治疗效率大大提高.氧化铁纳米颗粒由于其优异的磁性能在磁热疗应用的磁性纳米颗粒中脱颖而出,但存在着在交变磁场下加热效率受限的问题.具有高加热效率受限的磁性纳米粒子是磁热疗的必要条件.本文综述了近...     

不同碳源制备碳基固体酸及其在水解纤维素中的应用

采用磁性碳纳米管(CNTs)、葡萄糖、炼焦酚渣为碳源,制得碳基固体酸催化剂.通过XRD、FTIR、13C NMR和SEM/TEM对其结构和活性基团进行表征,并且以经过预处理的微晶纤维素为纤维素模型物,以总还原糖得率为考察指标,利用制备的碳基固体酸非均相催化水解纤维素,比较了3种碳源制得的碳基固体酸在水解纤维素中的水解效率.研究结果表明,与传统原料葡萄糖制得的碳基固体酸相比,酚渣基固体酸碳环上除了含有酚羟基、羧基和磺酸基外,还含有其它碳基固体酸不具备的烷基侧链,这一结构优势对碳基固体酸催化剂的催化活性具有促进作用,能够提高碳基固体酸催化剂的水解效率;碳纳米管固体酸尽管具有致密的碳层结构、磺化后磺酸密度低,但高比表面积使其在非均相催化水解纤维素中表现出较高的活性.     

磁载纳米TiO2光催化剂的研究进展

磁载纳米TiO2光催化剂作为一种复合功能材料,不仅具有较高的催化活性,而且在外加磁场下容易回收分离,在污水处理方面有着诱人的应用前景.综述了磁载纳米TiO2光催化剂的磁粒子的制备和TiO2的负载方法,详细阐述了其磁性能和光催化性能,展望了磁载纳米TiO2光催化剂未来的发展和应用.     

纳米粒子在固体基质表面的吸附

分析了与纳米粒子在固体基质表面的吸附机理相关的问题,综述了一些纳米粒子在固体基质表面上的吸附.通过控制纳米粒子和固体基质的组成,对纳米粒子和固体基质表面进行修饰等,可以使溶液中的纳米粒子靠静电作用、疏水作用、络合作用、氢键、磁性作用、粒子之间的毛细作用等在固体基质表面上吸附.在纳米粒子吸附的过程中,水力作用对吸附有重要影响.纳米粒子被固体基质表面吸附的可逆性一般较差.结合吸附机理分析了金纳米粒子在无机和有机固体基质表面上的吸附、铂纳米粒子在聚电解质表面上的吸附、带正电的发光纳米粒子在纤维上的吸附、磁性纳米粒子在磁性基质上的吸附以及量子点在藻细胞上的吸附等.在上述分析的基础上展望了纳米粒子在固体基质表面上吸附的研究方向.     

NixCo0.85-xSe中空纳米球的溶液化学法合成、双功能特性及锌空电池应用（英文）

合成高活性、低成本、双功能特性的电催化剂是目前发展新能源材料的重要任务.过渡金属硒化物具有较高的电导特性、可调节的物理化学特性等,成为了开发高效氧还原和氧析出催化剂的研究热点.本文采用多元醇溶液化学法合成了具有较大比表面积的NixCo0.85-xSe中空纳米球.该催化剂的ORR起始电位达到0.89 V,OER在10 mA cm^-2电流密度下的过电位达到305 mV.以NixCo0.85-xSe中空纳米球为空气电极、锌片为阴极组成的锌空电池具有良好的比容量和循环稳定性.NixCo0.85-xSe中空纳米球优异的催化性能主要归因于较大的比表面积、Ni和Co的协同催化特性以及良好的导电性.本文为设计高效的锌空电池催化剂提供了良好的理论基础和实验支持.     

纤维素基材料负载金属纳米粒子催化降解研究进展

由于金属纳米粒子具有高催化活性、反应选择性和易于制备等特点,其被认为是化学反应中的优异催化剂,但存在着高成本、难分离、易团聚、不可回收再利用等缺点。纤维素是迄今最丰富的可再生天然聚合物,广泛存在于高等植物、动物及细菌中,而又由于其高比表面积、较好的稳定性及化学可修饰性,因此纤维素基材料可以作为金属纳米粒子的良好载体。对近年来纤维素基材料负载金属纳米粒子催化剂的制备及催化性能进行了综述,以便有关科研人员了解多方位的有效尝试方法和探讨的途径。     

Recent Progress in Metal‐Free Covalent Organic Frameworks as Heterogeneous Catalysts

Covalent organic frameworks (COFs), connecting different organic units into one system through covalent bonds, are crystalline organic porous materials with 2D or 3D networks. Compared with conventional porous materials such as inorganic zeolite, active carbon, and metal‐organic frameworks, COFs are a new type of porous materials with well‐designed pore structure, high surface area, outstanding stability, and easy functionalization at the molecular level, which have attracted extensive attention in various fields, such as energy storage, gas separation, sensing, photoluminescence, proton conduction, magnetic properties, drug delivery, and heterogeneous catalysis. Herein, the recent advances in metal‐free COFs as a versatile platform for heterogeneous catalysis in a wide range of chemical reactions are presented and the synthetic strategy and promising catalytic applications of COF‐based catalysts (including photocatalysis) are summarized. According to the types of catalytic reactions, this review is divided into the following five parts for discussion: achiral organic catalysis, chiral organic conversion, photocatalytic organic reactions, photocatalytic energy conversion (including water splitting and the reduction of carbon dioxide), and photocatalytic pollutant degradation. Furthermore, the remaining challenges and prospects of COFs as heterogeneous catalysts are also presented.     

再论载体材料与贵金属催化剂——粉末冶金多孔金属应当是贵金属催化剂的合理载体材料

理论分析和实验结果表明催化过程中催化剂不参加化学反应,催化剂本身不发生化学变化,化学反应模式催化循环反应不可能发生,1902年提出的化学反应模式的催化循环原理(Sabatier's principle and Boudar'ts prin-ciple)难以令人信服。简述了触媒理论的逻辑推理及实验验证。触媒理论认为催化循环是催化剂质点内运动的电子轨道变形与恢复的循环,催化剂(或促进剂)有助于变形了的轨道恢复,而毒化剂则使变形了的轨道进一步变形;认为载体材料对贵金属催化剂催化活性的影响犹如催化剂(或促进剂)或毒化剂。凡是电负性大于贵金属催化剂的酸性材料作为载体都会降低金属催化剂催化活性,为了达到相同的转化率,必须要用较多的贵金属催化剂。Cl、O、N、C、S、P、SiO2、Al2O3、B2O3、硅藻土以及菫菁石陶瓷等都是酸性元素或材料。凡是电负性小于贵金属的碱性材料和过渡族元素都能提高贵金属的催化活性,如果达到同样的排放标准,则可以节省许多贵金属。汽车尾气净化催化剂用的Fe-Cr-Al金属卷片蜂窝载体优于陶瓷蜂窝载体。粉末冶金多孔金属蜂窝载体的最大优点是涂层量多而又不易剥落,起燃温度低,远优于金属卷片蜂窝载体。     

Multi-field driven hybrid catalysts for CO2 reduction: Progress,mechanism and perspective

Light, heat and electricity are three main types of essential energy that drive various kinds of chemical reactions. Although current photocatalysts, thermocatalysts and electrocatalysts provide effective solutions, great obstacles remain when considering the energy cost and production efficiency in CO₂ reduction. To promote the CO₂ transformation into value-added chemicals and realize net reduction, hybrid catalysts driven by related physical fields have been developed and exhibited great merits in terms of product yield, energy efficiency and tuning dimension. By posing impacts on the reactive intermediates or carriers transport, emerging synergetic field effects in multi-field catalysis have been proven to be beneficial in various reactions. Here, we clarify the correlations among several tuning fields during catalytic process, including light, thermal, electric, magnetic and mechanical fields, then classify them into photo-, thermal- or electric-dominant catalysis. This review study on multi-field involved catalytic strategy reveals the development of hybrid catalysts, and proposes further perspective in both theoretical design and practical applications.     

Heterostructures Based on 2D Materials: A Versatile Platform for Efficient Catalysis

The unique structural and electronic properties of 2D materials, including the metal and metal‐free ones, have prompted intense exploration in the search for new catalysts. The construction of different heterostructures based on 2D materials offers great opportunities for boosting the catalytic activity in electo(photo)chemical reactions. Particularly, the merits resulting from the synergism of the constituent components and the fascinating properties at the interface are tremendously interesting. This scenario has now become the state‐of‐the‐art point in the development of active catalysts for assisting energy conversion reactions including water splitting and CO₂ reduction. Here, starting from the theoretical background of the fundamental concepts, the progressive developments in the design and applications of heterostructures based on 2D materials are traced. Furthermore, a personal perspective on the exploration of 2D heterostructures for further potential application in catalysis is offered.     

矿物在合成纳米炭管中的催化作用

采用了电弧放电方法合成纳米炭管,在使用Ｆｅ、Ｃｏ、Ｎｉ、Ｔｉ、Ｚｒ等金属元素作催化剂的基础上,探索天然矿物－黄铁矿（ＦｅＳ２）、磁黄铁矿（Ｆｅ１－ｘＳ）、方铅矿（ＰｂＳ）、磁铁矿（ＦｅＦｅ２Ｏ４）、刚玉（Ａｌ２Ｏ３）及合成ＦｅＣｌ３、ＮａＣｌ、ＫＣｌ等化合物作催化剂合成纳米炭管的途径,讨论其催化机理。实验说明：用矿物（化合物）作催化剂合成纳米炭管是可行的,并有应用潜力,其催化效果与电子层结构、化合物键性类型、晶体缺陷等密切相关。就催化效果而言,总体上表现出过渡金属元素催化效果优于非过渡金属元素,晶体结构中共价键程度高的化合物（含金属键或改性的共价键的化合物）催化效果好于离子键程度高的化合物。     

Perovskite-type catalytic materials for environmental applications

Abstract

Perovskites are mixed-metal oxides that are attracting much scientific and application interest owing to their low price, adaptability, and thermal stability, which often depend on bulk and surface characteristics. These materials have been extensively explored for their catalytic, electrical, magnetic, and optical properties. They are promising candidates for the photocatalytic splitting of water and have also been extensively studied for environmental catalysis applications. Oxygen and cation non-stoichiometry can be tailored in a large number of perovskite compositions to achieve the desired catalytic activity, including multifunctional catalytic properties. Despite the extensive uses, the commercial success for this class of perovskite-based catalytic materials has not been achieved for vehicle exhaust emission control or for many other environmental applications. With recent advances in synthesis techniques, including the preparation of supported perovskites, and increasing understanding of promoted substitute perovskite-type materials, there is a growing interest in applied studies of perovskite-type catalytic materials. We have studied a number of perovskites based on Co, Mn, Ru, and Fe and their substituted compositions for their catalytic activity in terms of diesel soot oxidation, three-way catalysis, N₂O decomposition, low-temperature CO oxidation, oxidation of volatile organic compounds, etc. The enhanced catalytic activity of these materials is attributed mainly to their altered redox properties, the promotional effect of co-ions, and the increased exposure of catalytically active transition metals in certain preparations. The recent lowering of sulfur content in fuel and concerns over the cost and availability of precious metals are responsible for renewed interest in perovskite-type catalysts for environmental applications.     

A new bio-inspired route to metal-nanoparticle-based heterogeneous catalysts

Onion-type multilamellar vesicles are made of concentric bilayers of organic surfactant and are mainly known for their potential applications in biotechnology. They can be used as microreactors for the spontaneous and controlled production of metal nanoparticles. This process does not require any thermal treatment and, hence, it is also attractive for material sciences such as heterogeneous catalysis. In this paper, silver-nanoparticle-based catalysts are prepared by transferring onion-grown silver nanoparticles onto inorganic supports. The resulting materials are active in the total oxidation of benzene, attesting that this novel bio-inspired concept is promising in inorganic catalysis.     

Perovskite-type catalytic materials for environmental applications

Perovskites are mixed-metal oxides that are attracting much scientific and application interest owing to their low price, adaptability, and thermal stability, which often depend on bulk and surface characteristics. These materials have been extensively explored for their catalytic, electrical, magnetic, and optical properties. They are promising candidates for the photocatalytic splitting of water and have also been extensively studied for environmental catalysis applications. Oxygen and cation non-stoichiometry can be tailored in a large number of perovskite compositions to achieve the desired catalytic activity, including multifunctional catalytic properties. Despite the extensive uses, the commercial success for this class of perovskite-based catalytic materials has not been achieved for vehicle exhaust emission control or for many other environmental applications. With recent advances in synthesis techniques, including the preparation of supported perovskites, and increasing understanding of promoted substitute perovskite-type materials, there is a growing interest in applied studies of perovskite-type catalytic materials. We have studied a number of perovskites based on Co, Mn, Ru, and Fe and their substituted compositions for their catalytic activity in terms of diesel soot oxidation, three-way catalysis, N₂O decomposition, low-temperature CO oxidation, oxidation of volatile organic compounds, etc. The enhanced catalytic activity of these materials is attributed mainly to their altered redox properties, the promotional effect of co-ions, and the increased exposure of catalytically active transition metals in certain preparations. The recent lowering of sulfur content in fuel and concerns over the cost and availability of precious metals are responsible for renewed interest in perovskite-type catalysts for environmental applications.     

Functionalization of Hollow Nanomaterials for Catalytic Applications: Nanoreactor Construction

Hollow nanomaterials have attracted a broad interest in multidisciplinary research due to their unique structure and preeminent properties. Owing to the high specific surface area, well‐defined active site, delimited void space, and tunable mass transfer rate, hollow nanostructures can serve as excellent catalysts, supports, and reactors for a variety of catalytic applications, including photocatalysis, electrocatalysis, heterogeneous catalysis, homogeneous catalysis, etc. Based on state‐of‐the‐art synthetic methods and characterization techniques, researchers focus on the purposeful functionalization of hollow nanomaterials for catalytic mechanism studies and intricate catalytic reactions. Herein, an overview of current reports with respect to the catalysis of functionalized hollow nanomaterials is given, and they are classified into five types of versatile strategies with a top‐down perspective, including textual and composition modification, encapsulation, multishelled construction, anchored single atomic site, and surface molecular engineering. In the detailed case studies, the design and construction of hierarchical hollow catalysts are discussed. Moreover, since hollow structure offers more than two types of spatial‐delimited sites, complicated catalytic reactions are elaborated. In summary, functionalized hollow nanomaterials provide an ideal model for the rational design and development of efficient catalysts.     

脂肪酸甲酯的合成及综合应用

脂肪酸甲酯作为一种新型环保可再生资源而受到广泛的关注。分析介绍了脂肪酸甲酯在不同领域的应用。重点阐述了脂肪酸甲酯在表面活性剂、树脂的合成、农药助剂方面以及化工领域方面的应用。同时,还介绍了合成脂肪酸甲酯的制备工艺及催化方法,包括传统液体酸碱催化、固体酸碱催化剂、离子液体催化、生物酶催化及新型催化技术。