阴离子交换膜燃料电池阳极催化剂的研究进展

阴离子交换膜燃料电池(AEMFC)可使用非贵金属催化剂,且电极反应速率快。阳极催化剂的选择和制备对提高燃料氧化速率和燃料电池的电流密度及降低成本等有很大影响。本文从阴离子交换膜阳极催化剂的种类、制备方法,催化剂的载体等角度对阳极催化剂的研究现状进行分析。分析表明,在阳极催化剂中掺杂金属、金属氧化物或非金属氧化物,能充分发挥各元素的协同作用,从而提高催化剂的电催化性能;改进制备方法可以提高催化剂的比表面积,改变元素的分布。对催化剂载体进行改性以改善载体自身的孔径分布,提高比表面积和稳定性,或寻求导电性好、比表面积大、耐腐蚀的新载体材料(如SiC、Ti等),均可以提高催化剂的载量和催化剂在载体上的分散度等,从而提高阴离子交换膜燃料电池的性能。     

主链结构对阴离子交换膜碱稳定性的影响

碱性阴离子交换膜燃料电池(AAEMFCs)可使用低成本的非Pt催化剂,具有反应高效及环境友好等优点,因可在一定程度上取代质子交换膜燃料电池(PEMFCs)而备受关注.阴离子交换膜(AEMs)作为AAEMFCs的核心部件,需要兼备优异的OH-传输性能、机械性能、热稳定性及碱稳定性等.但目前AEMs仍面临的巨大挑战是耐碱性...     

阴离子交换膜离子传导率与耐碱稳定性研究进展

碱性膜电解水制氢和燃料电池技术是氢能产业链上的重要产氢和用氢技术。作为碱性膜电解槽及燃料电池的核心部件，阴离子交换膜承担着传递氢氧根离子、阻隔气体渗透、分隔正负两极的重要作用，决定着电化学过程效率和性能.现有阴离子交换膜的氢氧根传导率偏低和耐碱稳定性不高的问题严重制约着产氢和氢能转化效率.本文综述了近年来面向碱性膜电解水制氢和燃料电池应用的阴离子交换膜的发展动态，特别是在强化离子传导率、提高耐碱稳定性方面的方法和进展，以及膜材料化学组成和结构对膜性能的影响.     

碱性燃料电池用咪唑类阴离子交换膜研究进展

近年来,阴离子交换膜燃料电池的发展受到了广泛关注。开发具有碱稳定性能优异,电导率高的阴离子交换膜材料成为了研究的热点。阴离子交换膜(AEMs)主要由聚合物骨架和阳离子基团组成,这两者是影响膜碱稳定性和电导率的重要因素。综述了用于阴离子交换膜的咪唑功能化聚合物的制备,咪唑类阴离子交换膜和聚苯并咪唑类阴离子交换膜的碱稳定性、电导率等性能;同时,对于含有咪唑阳离子交换基团的阴离子交换膜的结构设计进行了分析和展望。     

燃料电池用质子交换膜的研究进展

对燃料电池用质子交换膜的研究进展进行了简要的概述,特别是从膜材料角度分类．较详细的介绍了全氟化质子交换膜,部分氟化质子交换膜,接枝、交联、共混型质子交换膜等的特性及最新的研究状况,并对其发展前景进行了探讨．     

阴离子交换膜渗析法回收含硫酸钠的高浓度硫酸废水

根据Fick扩散定律 ,提出了测定H2 SO4和Na2 SO4在阴离子交换膜中扩散速度的方法 .静态法测定结果显示 ,对含 2 5 0～ 3 5 0g/LH2 SO4、1 0 0～ 1 2 0g/LNa2 SO4的废水 ,常温下 ,A2 0 和 3 3 62BW膜中H 平均扩散速度分别为 8.0× 1 0 -4m/h和 7.8× 1 0 -4m/h,Na 平均扩散速度分别为 5 .9× 1 0 -5m/h和 6.6× 1 0 -5m/h,这预示两膜都能实现废酸中H2 SO4和Na2 SO4的有效分离 .动态法分离废酸结果表明 ,H2 SO4回收率达 83 .4% ,回收酸中Na2 SO4含量下降至 5 .2 g/L     

高耐碱性交联型聚苯醚阴离子交换膜的制备

以溴化聚苯醚(BPPO)为主链,N,N-二甲基己胺(DMHA),N,N-二异丙基乙胺(DIEA)和三乙胺(TEA)为季铵化试剂,N,N,N′,N′-四甲基-1,6-己二胺为交联剂制备了一系列交联型阴离子交换膜(AEMs),并对交联膜物理和电化学性能进行了表征与测试.结果表明,膜具有明显的微相分离结构、高的离子电导率、优异的尺寸稳定性和化学稳定性.其中接枝N,N-二异丙基乙胺的膜(c-PPO-DIEA)离子电导率在80℃下可达到72.3 mS/cm;在1 mol/L NaOH中经480 h的耐碱性测试发现,膜c-PPO-DIEA的离子电导率能够保留80%以上,表现出良好的耐碱性;将该膜组装成单电池测试,开路电压为0.983 V,在80℃下电流密度200 mA/cm~2时其功率密度达到89 mW/cm~2.     

不同构型的支化型聚芳烃阴离子交换膜的制备

通过超酸催化制备了一系列不同构型的支化型聚芳烃阴离子交换膜(AEMs),考察支化单体结构对AEMs性能的影响.结果表明，在相似的离子交换容量(IEC)下，支化结构的AEMs比直链型AEM的离子电导率和耐碱性更优异，柔性支化聚联苯三苯基甲烷螺环阳离子(PBTMPASU)膜的离子电导率优于刚性支化的聚联苯三苯基苯螺环阳离子(PBTBPASU)和聚联苯三蝶烯螺环阳离子(PBTPASU)膜.在80℃下，柔性支化PBTMPASU膜的OH^-电导率达128.2 mS/cm,在2 mol/L NaOH溶液中进行1 080 h的耐碱性测试后，OH^-电导率保留了94.1%.此外，基于PBTMPASU膜制备的单电池在1 167.0 mA/cm²的电流密度下峰值功率密度高达559.9 mW/cm².     

柔性含醚季鏻侧链聚砜阴离子交换膜研究

燃料电池为氢能高效利用提供了解决方案,阴离子交换膜是燃料电池的核心部件。季鏻碱性功能基团常连接大体积供电基团提升耐碱性,但阻碍OH^-传导。本文提出具有高传导和碱稳定性的柔性含醚季鏻功能侧链,季鏻阳离子与聚砜主链间的含醚脂肪间隔基团增强了侧链柔性,促进季鏻功能基团聚集;醚氧原子比N、C原子电负性更强,可提高亲水性;季鏻连接的三(2,4,6-三甲氧基苯基)大空间位阻通过阻隔OH^-进攻提升膜的碱稳定性。结果表明,柔性含醚季鏻侧链型聚砜阴离子交换膜显示出极低的溶胀率(约10%),较高的氢氧根离子电导率(80℃下为79.6 mS/cm)和优异的耐碱性(80℃、1 mol/L NaOH热碱溶液浸泡168 h后,氢氧根离子电导率保持率超过90%,而拉伸强度仅下降约2%).     

渗析法处理氨基酸—盐酸混合液的实验研究

用盐酸溶液在不同渗析条件下考察了聚砜型阴离子交换膜的静态和动态行为．用渗析法处理氨基酸和盐酸的混合液，取得了较为满意的效果．     

Nitrate determination using anion exchange membrane and mid-infrared spectroscopy

This study investigates the combined use of an anion exchange membrane and transmittance mid-infrared spectroscopy for determining nitrate concentration in aqueous solutions and soil pastes. The method is based on immersing a small piece (2 cm(2)) of anion exchange membrane into 5 mL of solution or soil paste for 30 minutes, after which the membrane is removed, rinsed, and wiped dry. The absorbance spectrum of the charged membrane is then used to determine the amount of nitrate sorbed on the membrane. At the levels tested, the presence of carbonate or phosphate does not affect the nitrate sorption or the spectrum of the charged membrane in the vicinity of the nitrate band. Sulfate affects the spectrum of the charged membrane but does not prevent nitrate determination. For soil pastes, nitrate sorption is remarkably independent of the soil composition and is not affected by the level of soil constituents such as organic matter, clay, and calcium carbonate. Partial least squares analysis of the membrane spectra shows that there exists a strong correlation between the nitrate charge and the absorbance in the 1000-1070 cm(-1) interval, which includes the v(1) nitrate band located around 1040 cm(-1). The prediction errors range from 0.8 to 2.1 mueq, which, under the specific experimental conditions, corresponds to approximately 2 to 6 ppm N-NO(3)(-) on a solution basis or 2 to 5 mg [N]/kg [dry soil] on a dry soil basis.     

3-Methyltrimethylammonium poly(2,6-dimethyl-1,4-phenylene oxide) based anion exchange membrane for alkaline polymer electrolyte fuel cells

Hydroxyl ion (OH^?) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl substitution and homogeneously quaternized to form an anion exchange membrane (AEM). ¹H NMR and FT-IR studies reveal successful incorporation of the above groups in the polymer backbone. The membrane is characterized for its ion exchange capacity and water uptake. The membrane formed by these processes show good ionic conductivity and when used in fuel cell exhibited an enhanced performance in comparison with the state-of-the-art commercial AHA membrane. A peak power density of 111 mW/cm² at a load current density of 250 mA/cm² is obtained for PPO based membrane in APEFCs at 30 °C.     

强碱性离子交换纤维的结构与性能

聚丙烯基强碱性离子交换纤维是由聚丙烯(polypropylene,简称PP)纤维与苯乙烯-二乙烯苯经60Coγ射线共辐照接枝后再经氯甲基化和胺化反应后制得的.为了研究自制的离子交换纤维的物理化学结构特点、活性功能基、微观形貌等特征.本文运用IR、DSC、SEM等现代测试表征技术结合元素分析、滴定曲线、交换容量、吸附动力学性能、机械强度和化学稳定性的测定等方法对离子交换纤维进行了较系统的分析.结果表明:自制的离子交换纤维具有强碱性离子交换纤维的结构特征和一定的化学稳定性.     

A review of the synthesis and characterization of anion exchange membranes

This review highlights advancements made in anion exchange membrane (AEM) head groups, polymer structures and membrane synthesis methods. Limitations of current analytical techniques for characterizing AEMs are also discussed. AEM research is primarily driven by the need to develop suitable AEMs for the high-pH and high-temperature environments in anion exchange membrane fuel cells and anion exchange membrane water electrolysis applications. AEM head groups can be broadly classified as nitrogen based (e.g. quaternary ammonium), nitrogen free (e.g. phosphonium) and metal cations (e.g. ruthenium). Metal cation head groups show great promise for AEM due to their high stability and high valency. Through “rational polymer architecture”, it is possible to synthesize AEMs with ion channels and improved chemical stability. Heterogeneous membranes using porous supports or inorganic nanoparticles show great promise due to the ability to tune membrane characteristics based on the ratio of polymer to porous support or nanoparticles. Future research should investigate consolidating advancements in AEM head groups with an optimized polymer structure in heterogeneous membranes to bring together the valuable characteristics gained from using head groups with improved chemical stability, with the benefits of a polymer structure with ion channels and improved membrane properties from using a porous support or nanoparticles.     

Use of Raman spectroscopy to evaluate the selectivity of bifunctional anion exchange resins for perchlorate

Raman spectroscopy is used to evaluate the selectivity of two bifunctional anion exchange resins, Purolite A-530 and Amberlite PWA-2. It was found that the adsorption of anions on the resins is described by a Frumkin isotherm, which is determined by the ion pair constant, K, and the Frumkin parameter, g. The ion pair constant, K, is a measure of the strength of interaction between the resin and the anion and the Frumkin parameter, g, takes into account interactions between adsorbed anions. Although both resins have a polystyrene backbone and trihexylammonium and triethylammonium functional groups, the Purolite A-530 resin exhibits greater selectivity for perchlorate. The only discernable differences between the two resins is that the Amberlite PWA-2 has a higher trihexylamine content and the Purolite A-530 resin exhibits greater cross-linking. How the trihexylamine/triethylamine content and the degree of cross-linking affects the performance of these resins is discussed.