作者对罗格斯大学的Thomas J. Emge博士和Wei Liu博士对小角度X射线衍射和粉末X射线衍射的分析和专业知识表示感谢。此外，作者承认郝王对N 2吸附实验的支持。

Al（OH） 3纳米粒子合成<ol><li>将1.40g氯化铝六水合物溶解在5.822g去离子水中。 </li><li>在磁力搅拌下，将2.778g L-精氨酸加入到氯化铝水溶液中。缓慢添加L-精氨酸，使加入的精氨酸溶解，不会形成大块或块状物;此外，缓慢添加降低局部碱度浓度，并为更可控制的水解提供条件。 </li><li>一旦所有精氨酸溶解到溶液中，在50℃下加热溶液72小时;在这一点上，溶液可能表现为混浊的悬浮液。 </li></ol> 2.用NaCl沉淀Al（OH） 3 <ol><li>准备一个长为49英寸和1.125直径的GPC色谱柱。在连续添加凝胶的步骤中包装凝胶，并允许水流过色谱柱以确保适当的包装，凝胶珠之间的空间最小。包装凝胶至约80％的柱子;凝胶填充量每次都变化，仅影响分离物种的保留时间。 </li><li>使用具有10mL注射器循环的HPLC泵将10mL合成的Al（OH） 3纳米颗粒悬浮液（在步骤1.3中制备）引入柱中。定制 - 使用外径大约为0.125英寸的管道进行注射器回路，并校准长度以输送10 mL注射样品。 </li><li> 以与dRI峰位置相关的间隔收集柱洗脱。将GPC输出连接到差分折射率（dRI）检测器的输入。 注意:分离的物质从GPC出来时，它们作为峰值出现在dRI检测器上，然后收集在125 mL瓶中。 GPC色谱柱产生两个分辨良好的峰，两个峰都被收集并用尺寸排阻色谱（SEC）和元素分析（EA）进行分析，以从铝中鉴别精氨酸资本投资者入境计划。收集的总体积将取决于GPC柱的尺寸，所用包装材料的总量以及用于洗脱柱的去离子水的流速。 <ol><li>以0.2 mL / min流速在100 min内收集大部分1号峰。 </li><li>一旦峰值出现在GPC色谱柱的RI检测器上，则以30分钟间隔收集洗脱液。 注意:改变间隔范围会改变所得纯化峰1材料的浓度和纯度。首先收集峰的小间隔是最好的，以确定哪一部分含有特定色谱柱的峰1种类的最高浓度和纯度。 </li></ol></li><li>准备1重量％的NaCl。 </li><li>将制备的NaCl溶液滴加到10mL纯化的Al（OH） 3纳米颗粒中;使用NaCl沉淀制备的材料不用于进一步的实验。 </li></ol> 3.制备Al-MCM-41 <ol><li> AC在真空烘箱中在120℃下真空吸收约1.0g MCM-41 3小时。 </li><li>通过将9.6926g的AlCl 3 ·6H 2 O与40.3074g去离子水相结合来制备50.0g氯化铝溶液。 </li><li>加入0.7g活化的MCM-41至50.0g氯化铝溶液（步骤3.2中制备）。 </li><li>允许足够的混合时间（1小时）以确保在整个MCM-41通道中扩散的AlCl 3的均匀性。 </li><li>在磁力搅拌下，将L-精氨酸加入到异相混合物中，使Arg / Al摩尔比为2.75。与步骤1.2类似，缓慢加入精氨酸，以使瞬时形成的絮凝物在继续添加之前重新溶解并减少精氨酸的聚集。 </li><li>一旦均匀，将混合物在50℃加热72小时。 </li><li>使用布氏漏斗在真空下过滤获得的异质溶液，并配备定性90 mm滤纸圈（或任何其他适当的滤纸）。 </li><li>用过量的去离子水洗涤过滤的白色粉末，以确保从生产的Al-MCM-41材料中除去未反应的氯化铝，精氨酸或水溶性副产物。 </li></ol>

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作者没有什么可以披露的。

氯化铝水溶液的制备需要使用氯化铝的结晶六水合物盐。尽管也可以使用无水形式，但是由于其显着的吸湿性能而不是优选的，这使得难以与铝的浓度一起使用并控制其浓度。值得注意的是，氯化铝溶液在制备后几天内应该使用，因为随着时间的推移，[Al（H 2 O） 6 ] 3+ aqua酸会水解产生不希望的副产物，从而最终降低最终的总产率和纯度产品。这里描述的合成方法用一定?...

由氢氧化铝制成的材料是用于各种工业应用的有希望的候选者，包括催化剂，药物，水处理和化妆品。 1，2，3，4 在升高的温度下，氢氧化铝在分解过程中吸收大量的热量，从而产生氧化铝（Al 2 O 3 ），使其成为有用的阻燃剂。已经使用计算和实验技术研究了四种已知的氢氧化铝多晶型物（ 即 ，三水铝矿，三羟铝石，北氨纶和石灰石），以提高我们对其形成和结构的理解。纳米尺度颗粒的制备是特别有意义的，因为它们具有显示量子效应和性质不同于其的性能的潜力大批量同行在各种条件7,8,9,10,11,12,13,14中容易制备尺寸为100nm量级的纳米微粒。 克服与进一步降低粒径相关的固有挑战是困难的;因此，只有少数情况下存在纳米晶粒尺寸在50nm左右的尺寸。据我们所知，没有关于小于50nm的纳米晶粒颗粒的报道。部分原因在于纳米粒子由于静电不稳定而倾向于聚集并且在胶体颗粒之间形成氢键的可能性很高，特别是在极性质子溶剂中。我们的目的是通过使用专门安全的成分和前体来合成小的Al（OH） 3纳米颗粒。在目前的工作中，通过掺入氨基酸（ 即 L-精氨酸）作为缓冲剂和稳定剂来抑制含水颗粒聚集。此外，据报道，含胍胍的精氨酸可防止氢氧化铝颗粒生长和聚集，得到平均粒径为10-30nm的水性胶态悬浮液。这里提出，精氨酸的两性和两性离子性质缓解了在轻度水解过程中氢氧化铝纳米颗粒的表面电荷，从而使颗粒生长超过30nm。虽然精氨酸不能够将粒径降低到10nm以下，但是通过利用"笼"限制效应在MCM-41的介孔中。 Al-MCM-41复合材料的表征显示了介孔二氧化硅中的超细氢氧化铝纳米颗粒，其平均孔径为2.7nm。

<table><tbody><tr><td>aluminum chloride hexahydrate</td><td>Alfa Aesar</td><td>12297</td><td></td></tr><tr><td>L-arginine</td><td>BioKyowa</td><td>N/A</td><td></td></tr><tr><td>aluminum hydroxide</td><td>Sigma Aldrich</td><td>239186</td><td></td></tr><tr><td>Bio-Gel P-4 Gel</td><td>Bio-Rad</td><td>150-4128</td><td></td></tr><tr><td>Mesoporous siica (MCM-41 type)</td><td>Sigma Aldrich</td><td>643645</td><td></td></tr></tbody></table>

facile preparation of ultrafine aluminum hydroxide particles with or without mesoporous mcm-41 in ambient environments

通过用铝精氨酸[Al（H 2 O） 6 ] 3+与L-精氨酸滴定至pH4.6，合成了纳米半纤维素水悬浮液。由于已知水合铝盐生产具有宽范围尺寸分布的各种各样的产品，各种最先进的仪器（ 即 27 Al / 1 H NMR，FTIR，ICP-OES ，TEM-EDX，XPS，XRD和BET）用于表征合成产物和副产物的鉴定。使用凝胶渗透色谱（GPC）柱技术分离由纳米颗粒（10-30nm）组成的产物。傅里叶变换红外（FTIR）光谱和粉末X射线衍射（PXRD）鉴定了纯化物质为氢氧化铝的三水铝矿多晶型物。无机盐（ 例如 NaCl）的添加引起悬浮液的静电去稳定，从而使纳米颗粒凝聚ld Al（OH） 3沉淀物，粒径大。通过利用这里描述的新型合成方法，将Al（OH） 3部分负载在MCM-41的高度有序的介孔骨架内，平均孔尺寸为2.7nm，产生具有八面体和四面体Al（O h / T d = 1.4）。使用能量色散X射线光谱法（EDX）测量的总Al含量为11％w / w，Si / Al摩尔比为2.9。大量EDX与表面X射线光电子能谱（XPS）元素分析的比较提供了铝硅酸盐材料中Al分布的了解。此外，与体积（2.9）相比，在外表面（3.6）上观察到更高的Si / Al比。 O / Al比的近似分别表明核心和外表面附近的Al（O） 3和Al（O） 4基团的浓度分别更高。新近开发的Al-MCM-41合成产物同时保持有序二氧化硅骨架的完整性，并且可用于其中水合或无水Al 2 O 3纳米颗粒是有利的应用。

纳米网合成通过用L-精氨酸将AlCl 3 ·6H 2 O（14重量％）滴定至最终的Arg / Al摩尔比为2.75来制备纳米锭。通过SEC来监测纳米晶粒颗粒的合成， SEC是一种广泛用于部分水解的氯化铝溶液的分析技术，能够鉴别任意指定为峰1,2,3,4和5的五个结构域。在这里，我们报道，粒径为10-30nm的纳米晶粒是在典型SEC分析...

Watch this Scientific Journal Video about Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments at JoVE.com

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

通过在MCM-41的介孔通道内进行笼式效应限制，通过[L-（H 2 O）] 3+与L-精氨酸的对照滴定制备超细氢氧化铝纳米颗粒悬浮液。

在环境环境中制备具有或不具有介孔MCM-41的超细氢氧化铝颗粒

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

facile-preparation-ultrafine-aluminum-hydroxide-particles-with-or

Research

JoVE Journal

Chemistry

10.8K 次观看.  Colgate-Palmolive Company. 通过在MCM-41的介孔通道内进行笼式效应限制，通过[L-（H 2 O）] 3+与L-精氨酸的对照滴定制备超细氢氧化铝纳米颗粒悬浮液。 

视频: Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

科研

化学

Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials.

Herein the procedures for plasma enhanced chemical vapor deposition of perfluoroalkanes on microporous materials such as metal-organic frameworks to enhance their stability and hydrophobicity are described. Furthermore, breakthrough testing of milligram quantities of samples is described in detail.

增强型氟烷烃的化学气相沉积等离子通过疏水金属 - 有机骨架的制备氨的去除

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

超高密度垂直对齐的任意基质的小分子有机纳米线阵列

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

工程学

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 &#176;C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder.

A &#8220;removable ceramic coating method&#8221; is presented in visual format for the synthesis of non-sintered and metal-terminated monometallic and bimetallic early transition metal carbide and nitride nanoparticles with tunable sizes and crystal structures.

单金属和双金属前过渡金属碳化物和氮化物纳米粒子的反相微乳液介导的合成

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The ...

Experimental Protocol to Investigate Particle Aerosolization of a Product Under Abrasion and Under Environmental Weathering

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering, which is a fundamental element to the approach of nanosafety-by-design of nanostructured products for their durable development. This approach is basically a preemptive one in which the focus is put on minimizing the emission of engineered nanomaterials' aerosols during the usage phase of the product's life cycle. This can be attained by altering its material properties during its design phase without compromising with any of its added benefits. In this article, an experimental protocol is presented to investigate the nanosafety-by-design of three commercial nanostructured products with respect to their mechanical solicitation and environmental weathering. The means chosen for applying the mechanical solicitation is an abrasion process and for the environmental weathering, it is an accelerated UV exposure in the presence of humidity and heat. The eventual emission of engineered nanomaterials is studied in terms of their number concentration, size distribution, morphology and chemical composition. The purpose of the protocol is to study the emission for test samples and experimental conditions which are corresponding to real life situations. It was found that the application of the mechanical stresses alone emits the engineered nanomaterials' aerosols in which the engineered nanomaterial is always embedded inside the product matrix, thus, a representative product element. In such a case, the emitted aerosols comprise of both nanoparticles as well as microparticles. But if the mechanical stresses are coupled with the environmental weathering, the experimental protocol reveals then the eventual deterioration of the product, after a certain weathering duration, may lead to the emission of the free engineered nanomaterial aerosols too.

In this article, an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering is presented. Results on the emission of engineered nanomaterials, in the form of aerosols are presented. The specific experimental set-up is described in detail.

实验协议来调查产品的粒子雾化在耐磨和环境下风化

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental ...

Nanothermite with Meringue-like Morphology: From Loose Powder to Ultra-porous Objects

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. Nanothermites are combustible materials made up of inorganic fuel and an oxidizer. In nanothermite foams, aluminum is the fuel and aluminum phosphate and tungsten trioxide are the oxidizing moieties. The highest flame propagation velocities (FPVs) in nanothermites are observed in loose powders and FPVs are strongly decreased by pelletizing nanothermite powders. From a physical standpoint, nanothermite loose powders are metastable systems. Their properties can be altered by unintentional compaction induced by shocks or vibrations or by the segregation of particles over time by settling phenomena, which originates from the density differences of their components. Moving from a powder to an object is the challenge that must be overcome to integrate nanothermites in pyrotechnic systems. Nanothermite objects must have both a high open porosity and good mechanical strength. Nanothermite foams meet both of these criteria, and they are prepared by dispersing a nano-sized aluminothermic mixture (Al/WO3) in orthophosphoric acid. The reaction of aluminum with the acid solution gives the AlPO4 &#34;cement&#34; in which Al and WO3 nanoparticles are embedded. In nanothermite foams, aluminum phosphate plays the dual role of binder and oxidizer. This method can be used with tungsten trioxide, which is not altered by the preparation process. It could probably be extended to some oxides, which are commonly used for the preparation of high performance nanothermites. The WO3-based nanothermite foams described in this article are particularly insensitive to impact and friction, which makes them far safer to handle than loose Al/WO3 powder. The fast combustion of these materials has interesting applications in pyrotechnic igniters. Their use in detonators as primers would require the incorporation of a secondary explosive in their composition.

This manuscript describes the synthesis of combustible aluminophosphate matrices by the reaction of orthophosphoric acid (H3PO4) with aluminum nanopowder. When this reaction is carried out with excess aluminum in the presence of tungsten trioxide nanopowder, it leads to a solid, porous nanothermite foam.

Nanothermite 与蛋白酥样形态学: 从松散的粉末到超多孔物体

The goal of the protocol described in this article is to prepare aluminothermic compositions (nanothermites) in the form of porous, monolithic objects. ...

Simultaneous Multi-surface Anodizations and Stair-like Reverse Biases Detachment of Anodic Aluminum Oxides in Sulfuric and Oxalic Acid Electrolyte

After reporting on the two-step anodization, nanoporous anodic aluminum oxides (AAOs) have been widely utilized in the versatile fields of fundamental sciences and industrial applications owing to their periodic arrangement of nanopores with relatively high aspect ratio. However, the techniques reported so far, which could be only valid for mono-surface anodization, show critical disadvantages, i.e., time-consuming as well as complicated procedures, requiring toxic chemicals, and wasting valuable natural resources. In this paper, we demonstrate a facile, efficient, and environmentally clean method to fabricate nanoporous AAOs in sulfuric and oxalic acid electrolytes, which can overcome the limitations that result from conventional AAO fabricating methods. First, plural AAOs are produced at one time through simultaneous multi-surfaces anodization (SMSA), indicating mass-producibility of the AAOs with comparable qualities. Second, those AAOs can be separated from the aluminum (Al) substrate by applying stair-like reverse biases (SRBs) in the same electrolyte used for the SMSAs, implying simplicity and green technological characteristics. Finally, a unit sequence consisting of the SMSAs sequentially combined with SRBs-based detachment can be applied repeatedly to the same Al substrate, which reinforces the advantages of this strategy and also guarantees the efficient usage of natural resources.

A protocol for fabricating nanoporous anodic aluminum oxides via simultaneous multi-surfaces anodization followed by stair-like reverse biases detachments is presented. It can be applied repeatedly to the same aluminum substrate, exhibiting a facile, high-yield, and environmentally clean strategy.

阳极氧化铝在硫酸和草酸电解质中的同时多表面 Anodizations 和阶梯式反向偏置剥离

After reporting on the two-step anodization, nanoporous anodic aluminum oxides (AAOs) have been widely utilized in the versatile fields of fundamental ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

快速超临界萃取制备催化气凝胶的制备与试验研究

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven effective in gas adsorption, separations, and catalysis. MOFs are most commonly synthesized as bulk powder, requiring additional processes to adhere them to functional devices and fabrics that risk decreasing the powder porosity and adsorption capacity. Here, we demonstrate a method of first coating fabrics with metal oxide films using atomic layer deposition (ALD). This process creates conformal films of controllable thickness on each fiber, while providing a more reactive surface for MOF nucleation. By submerging the ALD coated fabric in solution during solvothermal MOF synthesis, the MOFs create a conformal, well-adhered coating on the fibers, resulting in a MOF-functionalized fabric, without additional adhesion materials that may block MOF pores and functional sites. Here we demonstrate two solvothermal synthesis methods. First, we form a MIL-96(Al) layer on polypropylene fibers using synthetic conditions that convert the metal oxide to MOF. Using initial inorganic films of varying thicknesses, diffusion of the organic linker into the inorganic allows us to control the extent of MOF loading on the fabric. Second, we perform a solvothermal synthesis of UiO-66-NH2 in which the MOF nucleates on the conformal metal oxide coating on polyamide-6 (PA-6) fibers, thereby producing a uniform and conformal thin film of MOF on the fabric. The resulting materials can be directly incorporated into filter devices or protective clothing and eliminate the maladroit qualities of loose powder.

Solvothermal Synthesis of MIL-96 and UiO-66-NH2 on Atomic Layer Deposited Metal Oxide Coatings on Fiber Mats

Metal-organic frameworks are effective in gas storage and heterogeneous catalysis, but typical synthesis methods result in loose powders that are difficult to incorporate into smart materials. We demonstrate a method of first coating fabrics with ALD metal oxides, resulting in conformal films of MOF on the fabrics during solvothermal synthesis.

溶剂热合成 MIL-96 和 UiO-66-NH2在纤维垫上原子层沉积金属氧化物涂层上的合成

Metal-organic frameworks (MOFs), which contain reactive metal clusters and organic ligands allowing for large porosities and surface areas, have proven ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

超薄高性能金属-有机骨架膜的电泳结晶

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...