固体储氢材料的研究现状及发展趋势

氢能是清洁、可再生能源,可以提供稳定、高效和无污染的动力,在航空航天、汽车等领域有广阔的应用前景。在氢能技术的发展过程中,氢气的储存是至关重要的环节。氢气的储存分为高压压缩储存、低温液化储存以及固体材料的物理或化学吸附储存3种方式。其中,高压压缩储氢能耗高、储氢量小;低温液化储氢不但能耗高而且要求储存罐要有极其好的隔热性能。然而,固体材料储氢能有效弥补以上2种方式的不足,并且安全度高、运输方便。对近年来不同固体储氢材料的研究进展进行了简单的概括,分析了不同温度不同压力条件下不同材料的储氢性能及储氢容量,并展望了固体储氢材料的未来发展趋势。     

高容量储氢材料的研究进展

氢能是一种理想的二次能源.氢能开发和利用需要解决氢的制取、储存和利用3个问题,而氢的规模储运是现阶段氢能应用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种.固态储氢材料储氢是通过化学反应或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氖气储存方式.由轻元素构成的轻质高容量储氢材料,如硼氢化物、铝氢化物、氨摹氢化物等,理论储氢容量均达到5%(质量分数)以上,这为固态储氢材料与技术的突破带来了希望.新型储氢材料未来研究的重点将集中于高储氢容量、近室温操作、可控吸/放氢、长寿命的轻金属基氢化物材料与体系.     

高密度储氢材料研究进展

氢是一种清洁的燃料,氢能是未来有发展前景的新型能源之一.氢的储存是氢能现阶段开发和利用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种,其中高压气态储存或低温液态储存不能满足将来的储氢目标.固态储氢是通过化学或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氢气储存方式.高密度储氢材料由轻元素构成,包括铝氢化物、硼氢化物、氨基氢化物、氨硼烷等,理论储氢质量分数均达到5%以上.综述了高密度储氢材料的研究进展,认为高储氢容量、近室温操作、可控吸/放氢、长寿命的轻质氢化物材料有希望达到燃料电池和移动氢源应用的目标.     

水合物储氢技术的研究进展

氢能开发与利用的关键在于氢气的储存.目前现存的储氢技术和材料没有一种能满足工业实用的要求,作为一种新型的储氢材料,氢气水合物以其特有的优点被认为是一种比较理想的储氢材料.介绍了氢气水合物的特性,综述了水合物储氢技术的发现、发展、研究现状及优缺点.水合物储氢技术的关键在于使其生成条件更容易实现,最终达到提高水合物中储氢量的目的.由于在低温下生成氢气水合物的压力不需太高,因此低温制冷技术可以为氢气水合物的研制提供技术支持.     

人防地下工程PEMFC电站储氢方案的选择

PEMFC发动机除了应用于氢能汽车外,还可以应用于地下PEMFC电站。选择适当的储氢方案,对于电站稳定运行具有重大意义。分析了PEMFC电站储氢的特点,计算了储氢量,综合比较各种储氢方案的优劣,认为金属氢化物用于人防工程PEMFC电站储氢最适合。     

储氢材料研究进展

氢能作为一种新型的能量密度高的绿色能源,正引起世界各国的重视。储存技术是氢能利用的关键。储氢材料是当今研究的重点课题之一,也是氢的储存和输送过程中的重要载体。本文综述了目前已采用或正在研究的储氢材料,如金属(合金)储氢、碳基储氢、有机液体储氢、络合物储氢、硼烷氨储氢等材料,比较了各种储氢材料的优缺点,并指出其发展趋势。     

固体储氢材料研究进展

氢能作为一种极具发展潜力的清洁能源受到了越来越多的关注,而开发利用氢能的关键是解决氢气的储存问题。传统的高压气态储氢安全性差、储氢量小;低温液化储氢不仅需要高绝热的储存罐,而且储氢能耗很高。由于固体储氢材料能够很好的解决这些问题,成为了目前储氢技术研究的主要方向。目前主要的固体储氢材料有合金储氢、碳质储氢和络合物储氢,重点讨论了各类固体储氢材料的储氢原理、特点、研究现状及待解决的问题,并指出了其发展方向。     

金属氢化物储氢器的特点及其应用

氢能作为一种新型的高能量密度的绿色能源,储存和输送技术是其有效利用的关键。本文对气态、液态和固态这三种储氢方式进行了比较,结果表明固态储氢能量密度高且安全性好,优势明显;其中金属氢化物储氢易于携带和储存、可重复吸放氢,可促使氢气有效利用。本文阐述了金属氢化物储氢器的作用原理、特点,对其应用领域进行了说明。     

储氢材料的研究进展

氢能源以其可再生性和良好的环保效应成为未来最具发展潜力的能源载体,氢能被公认为人类未来的理想能源,而氢的储存是发展氢能技术的难点之一.本文综述了目前主要的储氢材料,如合金储氢、配位氢化物储氢、碳质材料储氢、有机液体氢化物储氢,并对未来的储氢材料发展进行了展望.     

储氢技术及其关键材料研究进展

氢能是未来能源结构中最具发展潜力的能源载体,氢的廉价制备、安全高效储送以及大规模应用是当今研究的重点,而氢能的储存是其中的关键性问题.本文综述了目前主要的储氢技术和储氢材料,如高压气态储氢、低温液态储氢、合金储氢、有机液体氢化物储氢、碳质材料储氢和金属有机骨架类聚合物储氢等,并对未来的研究方向进行了展望.     

氢敏材料与器件的研究进展

氢气的检测具有重要的学术意义和广阔的应用前景.氢敏传感器发展的关键在于高品质氢敏材料的研制.本文根据氢敏材料工作原理的不同,分别介绍了电化学型、半导体型、热导型和光学型四类氢敏传感器及相应氢敏材料的国内外研究最新进展,着重描述了各类氢敏材料的作用机制和改性途径,并展望了氢敏材料及氢敏传感器的发展方向.     

Interstitial Hydrogen Atom to Boost Intrinsic Catalytic Activity of Tungsten Oxide for Hydrogen Evolution Reaction

Tungsten oxide (WO₃) is an appealing electrocatalyst for the hydrogen evolution reaction (HER) owing to its cost-effectiveness and structural adjustability. However, the WO₃ electrocatalyst displays undesirable intrinsic activity for the HER, which originates from the strong hydrogen adsorption energy. Herein, for effective defect engineering, a hydrogen atom inserted into the interstitial lattice site of tungsten oxide (H_0.23WO₃) is proposed to enhance the catalytic activity by adjusting the surface electronic structure and weakening the hydrogen adsorption energy. Experimentally, the H_0.23WO₃ electrocatalyst is successfully prepared on reduced graphene oxide. It exhibits significantly improved electrocatalytic activity for HER, with a low overpotential of 33 mV to drive a current density of 10 mA cm⁻² and ultra-long catalytic stability at high-throughput hydrogen output (200 000 s, 90 mA cm⁻²) in acidic media. Theoretically, density functional theory calculations indicate that strong interactions between interstitial hydrogen and lattice oxygen lower the electron density distributions of the d-orbitals of the active tungsten (W) centers to weaken the adsorption of hydrogen intermediates on W-sites, thereby sufficiently promoting fast desorption from the catalyst surface. This work enriches defect engineering to modulate the electron structure and provides a new pathway for the rational design of efficient catalysts for HER.     

Hydrogen embrittlement in power plant steels

In power plants, several major components such as steam generator tubes, boilers, steam/water pipe lines, water box of condensers and the other auxiliary components like bolts, nuts, screws fasteners and supporting assemblies are commonly fabricated from plain carbon steels, as well as low and high alloy steels. These components often fail catastrophically due to hydrogen embrittlement. A brief overview of our current understanding of the phenomenon of such hydrogen damage in steels is presented in this paper. Case histories of failures of steel components due to hydrogen embrittlement, which are reported in literature, are briefly discussed. A phenomenological assessment of overall process of hydrogen embrittlement and classification of the various damage modes are summarized. Influence of several physical and metallurgical variables on the susceptibility of steels to hydrogen embrittlement, mechanisms of hydrogen embrittlement and current approaches to combat this problem are also presented.     

等离子体基脉冲偏压沉积DLC膜的氢分布和氢含量

用核反应分析方法,对等离子体基脉冲偏压沉积DLC膜的氢分布和氢含量进行了较系统的研究.结果表明,用等离子体基脉冲偏压沉积技术可获得较低氢含量的DLC膜;其氢含量范围约为6at％～17at％,且氢沿膜厚是均匀分布的,随等离子体密度及离化率降低,DLC膜的氢含量增加,荷能离子对生长表面的轰击具有较强的析氢作用,工作气体中引入氢气促进DLC膜中氢的析出.     

Hydrogen storage of a mechanically milled carbon material fabricated by plasma chemical vapor deposition

Abstract

Carbon materials were prepared by plasma chemical vapor deposition at different pressures without catalyst, and the structure and hydrogen storage characteristics of milled and unmilled samples of the materials were evaluated. Using this approach, we were able to fabricate graphite microcrystals with a crystallite size of several nanometers, and the crystallite size and surface area could be controlled by changing the pressure during plasma chemical vapor deposition. The hydrogen storage capacity of the unmilled materials was 0.3?wt%, but milling increased this value to 1.0?wt% by reducing the crystallite size and increasing the crystallite surface area.     

Control of Molecular Orientation in Organic Semiconductor Films using Weak Hydrogen Bonds

Use of the intrinsic optoelectronic functions of organic semiconductor films has not yet reached its full potential, mainly because of the primitive methodology used to control the molecular aggregation state in amorphous films during vapor deposition. Here, a universal molecular engineering methodology is presented to control molecular orientation; this methodology strategically uses noncovalent, intermolecular weak hydrogen bonds in a series of oligopyridine derivatives. A key is to use two bipyridin‐3‐ylphenyl moieties, which form self‐complementary intermolecular weak hydrogen bonds, and which do not induce unfavorable crystallization. Another key is to incorporate a planar anisotropic molecular shape by reducing the steric hindrance of the core structure for inducing π–π interactions. These synergetic effects enhance horizontal orientation in amorphous organic semiconductor films and significantly increasing electron mobility. Through this evaluation process, an oligopyridine derivative is selected as an electron‐transporter, and successfully develops highly efficient and stable deep‐red organic light‐emitting devices as a proof‐of‐concept.     

多孔氧化钛储氢的研究

采用配体辅助模板法,以异丙醇钛为前体,使用不同碳链长度的烷基胺为模板剂来制备一系列不同比表面积和孔容的多孔氧化钛材料。采用X射线衍射,氮气吸附实验,透射电镜对所制取材料进行表征,并在77K的条件下测量所制取材料的储氢性能。结果表明,在材料中拥有最大比表面积的材料具有最高的储氢量,在77K和65大气压的条件下其重量和体积储氢量分别为3.92wt%和21.48kg/m3。     

Formation and Transport of Atomic Hydrogen in Hot-Filament Chemical Vapor Deposition Reactors

In this paper we focus on diamond film hot-filament chemical vapor deposition reactors where the only reactant is hydrogen so as to study the formation and transport of hydrogen atoms. Analysis of dimensionless numbers for heat and mass transfer reveals that thermal conduction and diffusion are the dominant mechanisms for gas-phase heat and mass transfer, respectively. A simplified model has been established to simulate gas-phase temperature and H concentration distributions between the filament and the substrate. Examination of the relative importance of homogeneous and heterogeneous production of H atoms indicates that filament-surface decomposition of molecular hydrogen is the dominant source of H and gas-phase reaction plays a negligible role. The filament-surface dissociation rates of H2 for various filament temperatures were calculated to match H-atom concentrations observed in the literature or derived from power consumption by filaments. Arrhenius plots of the filament-surface hydrogen dissociation rates suggest that dissociation of H2 at refractory filament surface is a catalytic process, which has a rather lower effective activation energy than homogeneous thermal dissociation. Atomic hydrogen, acting as an important heat transfer medium to heat the substrate, can freely diffuse from the filament to the substrate without recombination.