储氢材料第一性原理计算的研究进展

综述了第一性原理计算在储氢材料研究中取得的成果和最新的进展。 第一性原理计算在储氢材料研究中的应用主要有以下4个方面： 1）研究纳米结构的储氢性能; 2） 研究储氢材料中掺杂和缺陷的作用及对储氢性能的影响; 3）研究储氢机理; 4）确定氢化物的几何结构以及预测新型储氢材料。 同时展望了第一性原理计算在储氢领域中的应用前景。     

沸石吸附储氢研究进展

沸石类微孔材料作为储氢介质的研究已成为近年来储氢领域中备受关注的热点问题,但对于其储氢机理、储氢容量及其影响因素的文献报道不尽一致。本文从吸附实验测定和理论计算模拟方面综述了各种结构类型沸石的吸附储氢的研究结果。重点分析了沸石的结构类型、硅铝比、阳离子类型及吸附实验条件差异对储氢量的影响,并讨论了超临界吸附理论模型的发展状况,最后探讨了沸石作为储氢材料的可行性和发展方向。     

储氢研究进展

氢能是21世纪主要的新能源之一。作为一种新型的清洁能源，氢的廉价制取、安全高效储存与输送及规模应用是当今研究的重点课题，而氢的储存是氢能应用的关键。储氢材料能可逆地大量吸放氢，在氢的储存与输送过程中是一种重要载体。本文综述了目前所采用或正在研究的主要储氢材料与技术，如高压气态储氢、低温液态储氢、金属氢化物储氢、化学氢化物储氢、吸附储氢、金属有机骨架储氢等，比较了各种储氢的优缺点，并指出其相关发展趋势。     

金属硼氢化物基固态储氢体系

氢气储存仍是制约氢经济推行的关键问题,开发一种高效、安全的储氢技术仍面临着巨大挑战。近年来,利用固态氢化物的化学吸附储氢技术由于可靠、结构紧密和高储氢容量的特点,被视为最有潜力的储氢手段之一。在众多固态氢化物储氢材料中,金属硼氢化物由于其极高的重量和体积储氢密度而备受关注。然而,金属硼氢化物热力学稳定,动力学缓慢,导致其吸/放氢温度高、速率慢、可逆性及循环稳定性差。本文从替代、复合、掺杂、纳米结构限域及相应的反应机理等角度总结了金属硼氢化物储氢材料的最新改性研究和应用,并提出了其中存在的问题和相应对策,同时指出了未来的研究方向。     

以车载储氢为目标的储氢材料研究进展

高效、安全的车载储氢技术研发是制约氢燃料电池车规模化商业应用的“瓶颈”环节。相比于高压氢瓶和低温液氢，材料基固态储氢在储氢密度、操作安全性和能源效率方面具有显著优势，因而被公认为最具发展前景的储氢方式。储氢材料历经数十年发展，尤其是随着近年来新型储氢材料的陆续发现，研究领域不断拓展，目前呈多材料体系、多储氢模式并行发展的格局。但与此同时，现有储氢材料／技术与车载储氢应用需求间的巨大差距并未因新型材料的发现而得到有效缩减，难于在温和操作温度下获取高储氢密度仍是各类储氢材料体系研究中面临的共性关键课题。     

机械合金化Mg/MmNi5-x(CoAlMn)x复合储氢合金的组织结构与吸氢特性

运用Ｘ射线衍射、扫描电及粒度分析等方法表征了机械合金化制备Ｍｇ／ＭｎＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ复合储氢合金的结构,通过ＰＣＴ曲线研究了基储氢性能。结果表明,在适当的球磨条件下能够获得纳米晶结构的Ｍｇ／ＭｎＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ复合储氢合金,ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ合金相彘,复合储氢合金的活化性能及储氢量有明显提高。此外,还考察了Ｍｇ含量对复合储氢合金的组织结构及储氢性能的影响。     

MH/Ni电池用稀土系储氢合金的失效及回收研究

探讨了深度过放电对MH／Ni电池负极储氢合金的影响。发现在过放电后，负极储氢合金的XRD结构图中，除了储氢合金的主相外，还出现了十分明显的Al(OH3),La(OH)3的衍射峰。结合各种情况下储氢合金失效的,原因利用化学处理及再熔炼的方法对失效MH／Ni电池的负极粉进行了回收实验，并对比了回收合金与原合金的结构及电化学性能。XRD测试结果表明回收合金与原合金的结构相同，均为CaCu5型。恒电流充放电实验发现，回收合金与原合金粉相比，放电容量接近，放电电位高。不寿命测试结果表明，回收合金较原合金容量衰减更缓慢。     

储氢材料的研究与进展

本文详细介绍了氢作为一种洁净二次能源载体的优点及发展潜力，综合描述了金属储氢材料、矿物多孔储氢材料、有机液态储氢材料的储氢特性及最新研究状况。最后就储氢材料的发展提出自己的见解。     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

以粉煤灰为原料制备ZSM-5沸石分子筛及其储氢性能

近年来，随着国内燃煤发电量的持续增长，作为燃煤电厂最主要的固体废弃物，粉煤灰的排放量也随着燃煤消耗的增长而急剧增加，引发了严峻的社会和环境问题。粉煤灰中的铝和硅元素含量很高，具有极高的提取价值。本文先对粉煤灰进行酸处理，除去粉煤灰中碱金属元素，提高硅铝比，之后采用水热合成法直接合成了高结晶度的ZSM-5沸石分子筛，此外还在水热合成时加入一定比例正硅酸乙酯（TEOS）后制备高硅铝比ZSM-5沸石分子筛，对二者在结构、结晶度和储氢性能方面进行了研究。结果表明，加TEOS后的ZSM-5的储氢性能比没有加TEOS的储氢量高，储氢量从0.584%增加到0.846%。     

微孔镧系配位聚合物

微孔配位聚合物与通常的微孔无机材料相比, 具有非常明显的优势. 而镧系离子特殊的光学和磁学性质, 更使得微孔镧系配位聚合物的研究成为热点. 本文简要地报道了微孔镧系配位聚合物的研究现状, 对一些微孔镧系配位聚合物的结构特点进行了描述, 讨论了影响微孔配位聚合物形成的主要因素. 一般来说, 线型配体往往能很好地将金属离子连接起来, 得到理想的微孔镧系配位聚合物; 选择合适的第二配体, 有利于构筑结构新颖的微孔镧系配位聚合物; 镧系收缩对能否形成微孔配位聚合物的影响并不明显, 只是轻稀土离子往往倾向于多结合一些小分子配体来满足更高的配位数.     

多孔聚合物贮氢材料的研究进展

微孔聚合物由于具有较高的比表面积,因此可用作物理吸附贮氢材料.本文通过比较0.1MPa、77K下自具微孔聚合物、超交联聚合物等多孔聚合物与其它多孔贮氢材料(如碳材料、金属有机网络等)的贮氢性能,阐述了比表面积、孔尺寸及孔形貌、与氢气的作用力等因素对多孔聚合物贮氢量的影响,由于合成超交联聚合物的单体多且孔形貌容易控制,因此超交联聚合物成为具有发展潜力的贮氢聚合物.     

Methyllithium‐Doped Naphthyl‐Containing Conjugated Microporous Polymer with Enhanced Hydrogen Storage Performance

Hydrogen storage is a primary challenge for using hydrogen as a fuel. With ideal hydrogen storage kinetics, the weak binding strength of hydrogen to sorbents is the key barrier to obtain decent hydrogen storage performance. Here, we reported the rational synthesis of a methyllithium‐doped naphthyl‐containing conjugated microporous polymer with exceptional binding strength of hydrogen to the polymer guided by theoretical simulations. Meanwhile, the experimental results showed that isosteric heat can reach up to 8.4 kJ mol^?1 and the methyllithium‐doped naphthyl‐containing conjugated microporous polymer exhibited an enhanced hydrogen storage performance with 150 % enhancement compared with its counterpart naphthyl‐containing conjugated microporous polymer. These results indicate that this strategy provides a direction for design and synthesis of new materials that meet the US Department of Energy (DOE) hydrogen storage target.     

多孔材料化学:从无机微孔化合物到金属有机多孔骨架

本文主要从无机微孔化合物和金属有机多孔骨架的合成化学和结构化学这两方面来介绍多孔材料化学的研究进展。多孔材料是一类具有规则孔结构的固态化合物,它们在催化、分离、离子交换等工业领域有着广泛的应用。硅铝酸盐是最为人们所熟知的微孔分子筛,经过半个多世纪的发展,人们又相继开发出磷酸盐、砷酸盐、锗酸盐、亚磷酸盐、硫酸盐、亚硒酸盐以及金属硫化物等类沸石无机微孔化合物。近十多年来,配位聚合物与金属有机多孔骨架开始大量兴起,为微孔化合物的多样化与组成的复杂性增添了新的领域。     

Metal-free Synthesis of Pyridyl Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution

Developing efficient, stable and sustainable photocatalysts for water splitting is one of the most significant methods for generating hydrogen. Conjugated microporous polymers, as a new type of organic semiconductor photocatalyst, have adjustable bandgaps and high specific surface areas, and can be synthesized using diverse methods. In this work, we report the design and synthesis of a series of pyridyl conjugated microporous polymers(PCMPs) utilizing polycondensation of aromatic aldehydes and aromatic ketones in the presence of ammonium acetate. PCMPs with different chemical structures were synthesized via adjusting monomers with different geometries and contents of nitrogen element, which could adjust the bandgap and photocatalytic performance. Photocatalytic hydrogen evolution rate(HER) up to1198.9 μmol·h~(-1)·g~(-1) was achieved on the optimized polymer with a specific surface area of 312 m~2·g~(-1) under UV-Vis light irradiation(λ320 nm).This metal-free synthetic method provides a new avenue to preparing an efficient photocatalyst for hydrogen evolution.     

Polymers of intrinsic microporosity (PIMs): organic materials for membrane separations, heterogeneous catalysis and hydrogen storage

This tutorial review describes recent research directed towards the synthesis of polymer-based organic microporous materials termed Polymers of Intrinsic Microporosity (PIMs). PIMs can be prepared either as insoluble networks or soluble polymers with both types giving solids that exhibit analogous behaviour to that of conventional microporous materials such as activated carbons. Soluble PIMs may be processed into thin films for use as highly selective gas separation membranes. Preliminary results also demonstrate the potential of PIMs for heterogeneous catalysis and hydrogen storage.     

Microporous Polymers as Potential Hydrogen Storage Materials

Microporous organic polymers offer the possibility of storing hydrogen safely at low temperatures and moderate pressures via physisorption. A range of polymers of intrinsic microporosity (PIMs) have been studied. The best PIM to date is based on a triptycene monomer and takes up 2.7% H₂ by mass at 10 bar/77 K. Hypercrosslinked polymers (HCPs) also show promising performance, particularly at pressures >10 bar. The form of the H₂ isotherm is influenced by the micropore distribution, a higher concentration of ultramicropores (pore size <0.7 nm), as found in PIMs, being associated with enhanced low pressure adsorption. The performance of polymers relative to other microporous materials (carbons and metal‐organic frameworks) is compared and promising methods to enhance the hydrogen uptake of microporous polymers are suggested.

     

Functional porous coordination polymers

The chemistry of the coordination polymers has in recent years advanced extensively, affording various architectures, which are constructed from a variety of molecular building blocks with different interactions between them. The next challenge is the chemical and physical functionalization of these architectures, through the porous properties of the frameworks. This review concentrates on three aspects of coordination polymers: 1). the use of crystal engineering to construct porous frameworks from connectors and linkers ("nanospace engineering"), 2). characterizing and cataloging the porous properties by functions for storage, exchange, separation, etc., and 3). the next generation of porous functions based on dynamic crystal transformations caused by guest molecules or physical stimuli. Our aim is to present the state of the art chemistry and physics of and in the micropores of porous coordination polymers.     

π‐Conjugated Microporous Polymer Films: Designed Synthesis,Conducting Properties,and Photoenergy Conversions

Conjugated microporous polymers are a unique class of polymers that combine extended π‐conjugation with inherent porosity. However, these polymers are synthesized through solution‐phase reactions to yield insoluble and unprocessable solids, which preclude not only the evaluation of their conducting properties but also the fabrication of thin films for device implementation. Here, we report a strategy for the synthesis of thin films of π‐conjugated microporous polymers by designing thiophene‐based electropolymerization at the solution–electrode interface. High‐quality films are prepared on a large area of various electrodes, the film thickness is controllable, and the films are used for device fabrication. These films are outstanding hole conductors and, upon incorporation of fullerenes into the pores, function as highly efficient photoactive layers for energy conversions. Our film strategy may boost the applications in photocatalysis, energy storage, and optoelectronics.     

共轭微孔聚合物及其复合材料的制备及应用

共轭微孔聚合物是一类具有扩展共轭体系的骨架材料,具有比表面积大、稳定性高、微孔大小和体积可精确调控等特点。由于其独特的结构特点,共轭微孔聚合物在各方面展现出巨大的应用潜力,本文综述了共轭微孔聚合物及复合材料的制备方法,以及共轭微孔聚合物在气体吸附和储存、污染物的富集、非均相催化、光发射、化学传感器、光捕集、电能存储等方面的应用。