纳米花型酶-无机杂化固定化酶研究进展

酶是一种绿色高效的生物催化剂,被广泛应用于工业生产中,为了更好地提升游离酶的性能,酶固定化技术应运而生.然而,与游离酶相比,固定化酶活性下降以及传质受限一直是酶固定化技术亟待解决的关键问题.作为一种新型酶固定化技术,纳米花型酶-无机杂化固定化酶因具有高比表面积、高酶活性和高催化效率且制备过程简单、绿色无污染而受到广泛关...     

纳米金杂化酶研究进展

随着纳米技术和生物技术的发展,将纳米颗粒材料与天然酶结合起来构建纳米杂化酶,可以解决酶的负载量低、活性和稳定性不好等问题.目前,新型纳米颗粒材料-纳米金被广泛应用于构建杂化酶体系.我们将从纳米金杂化酶的种类、制备方法、优势以及应用等方面对纳米金杂化酶的研究进展进行概述.     

非均相金属卟啉催化剂的研究进展

本文综述了近年来非均相金属卟啉催化剂的最新研究成果,对不同类型载体的结构特点、负载方法、及催化活性进行了详细阐述。负载后的金属卟啉配合物不仅避免了二聚,提高了稳定性和活性,而且表现出较高的形状和尺寸选择性。     

介孔金属膦酸盐杂化材料研究进展

介孔金属有机膦酸盐杂化材料由于同时结合了无机和有机组分的性质,可作为一种环境友好的多功能材料而备受关注. 介孔金属有机膦酸盐中的有机和无机组分不是简单的物理混合,而是在分子尺度上的融合. 合成膦酸盐所需有机前驱体主要为有机多聚膦酸及其相应的盐和酯类化合物,种类繁多,使得各种有机官能团被均匀地引入进金属膦酸盐的骨架中,呈现多功能作用,有效地扩展了其应用领域. 本文系统地综述了介孔金属有机膦酸盐的合成及在吸附、分离、催化、生物传感和药物控释等领域应用研究进展,并对介孔金属膦酸盐材料的发展方向和应用前景进行了展望.     

金属纳米复合催化剂合成与应用的最新进展

随着纳米技术的发展,金属纳米复合材料由于其特殊的物理化学性质和潜在的催化应用受到越来越多的关注。本文系统地介绍了金属纳米复合催化剂最新的研究进展。首先,我们介绍了一些金属纳米复合催化剂的合成方法。其次,为了更好的优化催化剂的结构与催化活性的关系,并深入理解催化反应机理,我们讨论了金属纳米复合催化剂一些重要因素（包括粒子粒径、形貌、组成、载体或配体）对催化活性和选择性的影响。最后,我们进一步介绍了金属纳米复合催化剂在还原不饱和化学键中的应用（N=O,N≡C和C=O）,同时还对金属纳米复合催化剂的发展方向进行了展望。     

金属纳米复合催化剂合成与应用的最新进展

随着纳米技术的发展,金属纳米复合材料由于其特殊的物理化学性质和潜在的催化应用受到越来越多的关注。本文系统地介绍了金属纳米复合催化剂最新的研究进展。首先,我们介绍了一些金属纳米复合催化剂的合成方法。其次,为了更好的优化催化剂的结构与催化活性的关系,并深入理解催化反应机理,我们讨论了金属纳米复合催化剂一些重要因素(包括粒子粒径、形貌、组成、载体或配体)对催化活性和选择性的影响。最后,我们进一步介绍了金属纳米复合催化剂在还原不饱和化学键中的应用(N=O,N≡C和C=O),同时还对金属纳米复合催化剂的发展方向进行了展望。     

木质素及其衍生物负载金属催化剂在有机合成中的应用研究进展

碳中和发展理念的提出使得生物质基催化剂的关注度不断提高,将木质素作为过渡金属催化剂的载体来制备非均相催化剂应用于有机合成领域,可以极大地提高木质素的利用价值.木质素结构中广泛存在的含氧官能团为金属催化剂的负载提供了多种结合位点,通过物理吸附/沉积、离子交换以及与羟基官能团通过静电络合可以有效地捕获金属粒子.首先介绍了木质素的结构,然后介绍了制备非均相催化剂的方法,重点介绍了木质素及其衍生物负载金属催化剂催化点击反应、Glaser反应、Huisgen [3+2]环加成反应、Heck反应、Suzuki反应、Sonogashira反应、Stille偶联反应、迈克尔加成/脱水串联反应、亲电开环反应、Fridel-Crafts型反应及乙烯聚合反应等,并对存在的问题和发展趋势进行了展望.     

以介孔分子筛为金属催化剂载体制备纳米碳管

 以不同的介孔分子筛作为金属催化剂载体,对催化合成纳米碳管进行了系统的研究,讨论了反应条件对纳米碳管纯度和产量的影响. 结果表明,不同的介孔分子筛对金属活性中心的形成、碳组分的扩散、纳米碳管的管径及形态均有明显的影响. 此外,金属的种类、状态和含量也影响纳米碳管的合成. 探索了合成高产量纳米碳管的条件,并对介孔分子筛上生长纳米碳管的特点进行了讨论.     

金属有机框架化合物在非均相催化反应中的应用

金属有机框架化合物(metal-organic frameworks,MOFs)是近年来出现的一种新型无机材料,不仅具有非常高的表面积和孔隙率,而且材料的框架结构丰富、可控,可用于气体吸附、生物医学以及磁性材料等,应用前景广阔。特别是MOFs在非均相催化反应中的应用更是吸引了大批学者的注意,研究发展非常迅速,已取得了许多成果。本文首先介绍了MOFs作为催化剂所具有的独特优点,实际应用中可能存在的问题,以及相应的解决方案;其次基于MOFs的三个结构要素系统总结了目前MOFs在非均相催化反应中的探索和应用;最后讨论了MOFs在非均相催化研究中需要重视的问题,以期为MOFs在非均相催化反应中的应用研究提供参考。     

Electrodynamics of Noble Metal Nanoparticles and Nanoparticle Clusters

In this paper we examine the electrodynamics of silver nanoparticles and of clusters of nanoparticles, with an emphasis on extinction spectra and of electric fields near the particle surfaces that are important in determining surface-enhanced Raman (SER) intensities. The particles and clusters are chosen to be representative of what has been studied in recent work on colloids and with lithographically prepared particles. These include spheres, spheroids, truncated tetrahedrons, and clusters of two or three of these particles, with sizes that are too large to be described with simple electrostatic approximations but small compared to the wavelength of light. The electrodynamics calculations are mostly based on the discrete dipole approximation (DDA), which is a coupled-finite element approach which produces exact or nearly exact results for particles of arbitrary size and shape if fully converged. Mie theory results are used to study the validity of the DDA for spherical particles, and we also study the validity of the modified long wavelength approximation (MLWA), which is based on perturbative corrections to the electrostatic limit, and of the single dipole per particle approximation (SDA). The results show how the dipole plasmon resonance properties and the electric field contours around the particle vary with particle shape and size for isolated particles. For clusters of particles, we study the effect of interparticle spacing on plasmon resonance characteristics. We also show that the quadrupole resonance is much less sensitive to particle shape and interparticle interactions than the dipole plasmon resonance. These results provide benchmarks that will be used in future comparisons with experiment.     

聚苯胺/贵金属复合纳米材料的可控合成及催化应用

导电高分子/贵金属复合纳米材料因其在催化、传感、表面增强拉曼、光热治疗等诸多领域的应用前景而受到广泛关注.本文主要介绍我们课题组近年来利用可控合成策略制备的负载型和包埋型两种结构聚苯胺/贵金属复合纳米材料,以及利用复合纳米材料的结构和功能特性,对其在多相催化领域的应用、结构与催化性能之间构效关系的探索.     

单分子层保护纳米 Au 粒子表面配位催化剂的制备及其应用

 贵金属纳米粒子由于其小尺寸效应而表现出特殊的催化性能. 综述了纳米 Au 粒子表面配位催化剂的制备方法及其在催化中的应用. 由于 Au 可与硫化物形成配位键, 所以硫化物可在 Au 表面形成有序单分子膜. 单分子膜保护的 Au 纳米粒子具有非常好的溶解性、分散性、稳定性, 以及由不同的表面功能团而导致的不同的催化性能. 该催化体系兼具均相催化剂和多相催化剂的特点, 这对开发新型催化剂具有重要的理论和实际意义.     

多核金属配合物模拟水解酶催化研究进展

对近年来双核及三核金属配合物作为水解酶模型催化水解反应的研究工作进行了综述,分别从模型物的设计要求、催化反应机理等方面进行了讨论,并对其今后的发展前景进行了展望。     

Metal Nanoparticle/Polymer Hybrid Particles: The Catalytic Activity of Metal Nanoparticles Formed on the Surface of Polymer Particles by UV-Irradiation

Summary: Polymer particles decorated with metal nanoparticles were prepared by UV-irradiation of polystyrene particles incorporating polymethylphenylsilane (PS/PMPS) and P[S-co-NIPAM]/PMPS particles (NIPAM: N-isopropyl acrylamide) in the presence of metal salts. The metal nanoparticle/polymer hybrid particles were used as a catalyst for the reduction of 4-nitrophenol with NaBH₄. The Pd- and Ag-P(S-co-NIPAM)/PMPS hybrid particles had larger metal nanoparticles and the lower catalytic activity than those of Pd- and Ag-PS/PMPS, respectively. The surface functional group of the polymer particles affected the formation of the metal nanoparticles and their catalytic activity.     

Metal Nanoparticle/Polymer Hybrid Particles: The Catalytic Activity of Metal Nanoparticles Formed on the Surface of Polymer Particles by UV-Irradiation

Summary: Polymer particles decorated with metal nanoparticles were prepared by UV-irradiation of polystyrene latex particles incorporating polymethylphenylsilane (PS/PMPS) and P[S-co-NIPAM]/PMPS particles (NIPAM: N-isopropyl acrylamide) in the presence of metal salts. The metal nanoparticle/polymer hybrid particles were used as a catalyst for the reduction of 4-nitrophenol with NaBH₄. The Pd- and Ag-P(S-co-NIPAM)/PMPS hybrid particles had larger metal nanoparticles and the lower catalytic activity than those of Pd- and Ag-PS/PMPS, respectively. The surface functional group of the polymer particles affected the formation of the metal nanoparticles and their catalytic activity.     

A New Concept for Advanced Heterogeneous Metal Catalysts

Oxide-supported metal catalysts, having always nano-sized structures in which the metal catalysts are prepared as highly dispersed nano-crystals (typically 1-20 nm) on support oxide particles that are often one to several orders of magnitude larger than the metal nano-particles, are an important class of heterogeneous metal catalysts that finds many applications in chemical/petrochemical industries, in environmental protection, in chemical sensors and in the manufacture of fine and special chemicals. It is believed that catalysis by supported metals is the oldest application of nanotechnology. The literature has been rich in nano-size effect of metal nanoparticles in the metal/oxide catalysts. However, it is until recently that the development of size-controlled synthesis of oxide nanoparticles has made it possible to study the nano-size effect of oxide-support particles. When the particle sizes of an oxide support are reduced to become comparable to the sizes of the active metal nanoparticles, the oxide could deviate dramatically from its function as a conventional support. Such metal/oxide catalysts consisting of comparably sized metal and oxide nanocrystals are better called metal/oxide nanocomposite catalysts or catalytic nanoarchitectures.In this presentation, several attempts with reducing the particle size of oxide supports (ZrO2, TiO2,MgO, Al2O3) to approach the metal/oxide nanocomposite concept will be discussed to emphasize the importance of the support size effect. Examples will be given on characteristics of nanocomposite Ni/oxide catalysts for the reforming of natural gas with CO2 and/or steam, and on Au/oxide catalysts for CO oxidation and hydrogenation of unsaturated organic compounds. It will be emphasized that systematic investigations into the size effects of both the metal and oxide nanoparticles approaching the metal/oxide nanocomposite concept can lead to advanced heterogeneous metal catalysts.Moreover, intensive practice of the nanocomposite concept would also lead to discovery of special size-dependent metal-oxide interaction and catalysis, which may provide new opportunity for performance enhancement of potential and existing catalysts.     

镍铁氰化物纳米粒子的合成及其多相催化无溶剂条件下苯甲醇氧化的潜能(英文)

Nickel hexacyanoferrate nanoparticles were synthesized and characterized using elemental analysis, thermal analysis, infrared spectroscopy, and X-ray diffraction. A FE-SEM image of the nickel hexacyanoferrate showed that it consists of nearly spherical particles with sizes ranging from 30 to 70 nm. The synthesized material was found to be a heterogeneous catalyst useful for the solvent-free oxidation of benzyl alcohol with H2O2 as an oxidant. A 36% conversion of benzyl alcohol to benzaldehyde was achieved under optimized reaction conditions using specific parameters such as the amount of catalyst, the temperature, the benzyl alcohol to H2O2 molar ratio, and the reaction time.     

金属/金属氧化物纳米粒子在不对称氢化和氢转移反应中的应用研究进展

近年来,金属/金属氧化物纳米粒子催化的不对称氢化和氢转移反应已经成为催化领域的前沿和研究热点之一. 金属/金属氧化物纳米粒子的催化模式类似于“纳米反应器”,底物可以通过有机包覆层扩散至催化中心,局部的高催化剂浓度通常可以极大地提高催化反应转换数（TON）和转化频率（TOF）. 在以纳米金属为催化活性中心方面,Orito纳米铂体系获得最多的关注,科学家们从手性修饰剂的结构改造、催化剂载体的选择、不同的反应介质、纳米催化剂的形貌和催化反应机理等方面开展了较为系统的研究,并取得重要进展. 此外,纳米钯、铑、钌、铱和铁等金属纳米催化剂也在烯烃、酮和亚胺等化合物的不对称氢化和氢转移反应中表现出良好的催化性能,特别是纳米铱和铁催化剂已获得95%以上的对映选择性. 在金属/金氧化物纳米粒子为催化剂载体方面,其催化不对称氢化及氢转移反应的效率及对映选择性可与均相催化剂相媲美,同时还解决了均相催化剂难于回收再循环的缺陷. 本文简要介绍了近年来手性金属纳米催化剂在不对称氢化和氢转移反应领域的研究进展,讨论了相关反应的催化机理,并对该领域仍存在的问题和未来的发展方向进行了展望.     

Pt-FeOx催化剂微结构对催化CO氧化性能的影响

借助较为成熟的纳米技术手段,采用PVP为保护剂、乙二醇为还原剂制备具有不同Pt/Fe比例的双金属纳米粒子,最终通过氧化处理获得具有不同微结构环境的纳米Pt-FeO_x催化剂,并以此为模型考察它们对CO氧化性能的影响。结果表明FeO_x物种的数量一方面影响Pt物种的价态,同时也影响Fe物种自身的氧化还原性质,这些性质直接和间接地影响着CO和氧分子的活化,Pt周围适量FeO_x物种的存在对构建高活性CO氧化催化剂有利。