燃料电池反应器在化学品与电能共生中应用

燃料电池作为能源转换装置能够高效地将化学能转化为电能,随着技术的发展人们将其作为反应器来完成高附加值的化学品的合成,同时产生一定的电能. 燃料电池反应器因具有反应条件温和、反应过程可控、产物选择性高、能源利用效率高等特点,而被广泛地应用于医药中间体的制备、气体分离、水处理等多个领域. 本文首先按照反应器中阴阳极区域发生反应的类型进行分类,介绍燃料电池反应器在化学品与电能联产中的研究现状和研究进展. 随后描述了燃料电池反应器中存在的问题,并依照催化剂、反应过程等方向对解决方案进行探讨. 最后,对几种新型燃料电池反应器的研究进行了简要的介绍并对其发展做出了展望.     

燃料电池反应器在化学品与电能共生中应用北大核心CSCD

燃料电池作为能源转换装置能够高效地将化学能转化为电能,随着技术的发展人们将其作为反应器来完成高附加值的化学品的合成,同时产生一定的电能.燃料电池反应器因具有反应条件温和、反应过程可控、产物选择性高、能源利用效率高等特点,而被广泛地应用于医药中间体的制备、气体分离、水处理等多个领域.本文首先按照反应器中阴阳极区域发生反应的类型进行分类,介绍燃料电池反应器在化学品与电能联产中的研究现状和研究进展.随后描述了燃料电池反应器中存在的问题,并依照催化剂、反应过程等方向对解决方案进行探讨.最后,对几种新型燃料电池反应器的研究进行了简要的介绍并对其发展做出了展望.     

甲醇水蒸汽重整微反应器性能研究

燃料电池具有工作效率高、无污染物排放等优点,因此,燃料电池技术的研究和开发受到各国政府和大公司的重视.燃料电池的最佳原料为氢,自从燃料电池诞生起,供氢与燃料电池本身都是同样重要的核心技术[1].甲醇水蒸汽重整制氢是近年来发展较快的制氢方法,具有操作方便、原料易得、反应条件温和、副产物少等优点,而且装置规模大小均宜,并可做成便携式来满足不同用户对氢源的要求[2].本文采用制氢微反应器进行甲醇水蒸汽重整实验,研究了反应温度、进料速度、水醇比和反应时间对甲醇转化率、CO2选择性等的影响.     

燃料电池聚合物电解质膜的研究进展

本文根据聚合物电解质膜燃料电池操作温度、使用的电解质和燃料的不同,将其分为高温质子交换膜燃料电池、低温质子换膜燃料电池、直接甲醇燃料电池和阴离子交换膜燃料电池,综述了它们所用电解质膜的最新进展.第一部分简要介绍了这4种燃料电池的优点和不足.第二部分首先介绍了Nafion膜的结构模型,并对平行柱状纳米水通道模型在介观尺度上进行了修正;接着分别对应用于不同燃料电池的改性膜的改性思路作了分析;最后讨论了用于不同燃料电池的新型质子交换膜的研究,同时列举了性能突出的改性膜和新型质子交换膜.第三部分介绍了阴离子交换膜的研究现状.第四部分对未来聚合物电解质膜的研究作了展望.     

直接氨固体氧化物燃料电池

塑性挤压成型阳极支撑管,采用真空浸涂法在阳极表面制备了均一、致密的氧化钇稳定的氧化锆电解质层,然后在电解质表面刷涂上阴极层,成功制备了阳极支撑型管状固体氧化物燃料电池.分别以氢气和氨气为燃料,考察了该管状固体氧化物燃料电池的电池性能.在800℃操作时,以氢气和氨气为燃料的电池最大输出功率密度分别为202和200 mW/cm2.表明氨气可以作为固体氧化物燃料电池的替代燃料.     

车用质子交换膜燃料电池材料部件

车用燃料电池主要包括质子交换膜燃料电池、金属-空气燃料电池等,其中质子交换膜燃料电池是目前车用燃料电池的主要开发对象(以下简称车用燃料电池)。经过全球范围内近十年的持续研发,车用燃料电池在能量效率、功率密度与比功率、低温启动等功能特性方面已经取得了突破性进展,新一轮的燃料电池汽车产业化浪潮正在迫近。然而,车用燃料电池的耐久性和成本还没达到预期商业化目标,是其产业化的最后障碍。探索和研发燃料电池用新型关键材料部件是解决这两大问题、推进其商业化进程的关键所在,也是车用燃料电池长期的研究重点和热点。本文系统地梳理了近几年来车用燃料电池质子交换膜、催化层、气体扩散层、双板板关键材料部件的研究进展和成果,并分类进行了简要评述,分析了其性能与商业化目标的差距。最后展望了车用燃料电池关键材料部件今后的发展方向。     

车用燃料电池系统耐久性研究

燃料电池的耐久性是燃料电池汽车的关键技术问题,车用燃料电池寿命需要达到5000小时以上才能满足汽车应用要求. 作者基于车用燃料电池失效模式的研究,通过优化系统设计和改进系统控制策略等,开发出长寿命的HySYS-30车用燃料电池系统,并采用车用动态工况,对所开发的燃料电池系统进行了6000小时以上的耐久性测试,6000小时的性能衰减率仅为8.1%.     

基于水溶性多金属氧酸盐的光催化燃料电池

以水溶性多金属氧酸盐作为光催化剂和电子载体构建了一种新型光催化燃料电池.该光催化燃料电池发生燃料的均相光催化降解反应,可实现在无光照情况下的持续放电.使用生物柴油副产物甘油作为燃料时,该光催化燃料电池的输出功率达0.24 m W/cm~2.在持续光照条件下,电池可长时间运转近50 h,电流稳定在0.75 m A/cm~2以上.甘油在电池中可持续循环放电,根据实际的反应程度可被转化为醛和酸,进一步氧化得到COx.对多种有机燃料的应用表明该光催化燃料电池具有广泛的适用性.     

燃料电池技术的发展与我国应有的对策

本文介绍了几种主要类型燃料电池的最新进展，基于世界发展趋势和我国具体情况，作者在碱性燃料电池，磷酸型燃料电池，溶融碳酸盐电池和聚合物电解质燃料电池方面提出了相应对策。以促进我国燃料电池的研究与开发。     

车用燃料电池系统耐久性研究北大核心CSCD

燃料电池的耐久性是燃料电池汽车的关键技术问题,车用燃料电池寿命需要达到5000小时以上才能满足汽车应用要求.作者基于车用燃料电池失效模式的研究,通过优化系统设计和改进系统控制策略等,开发出长寿命的Hy SYS-30车用燃料电池系统,并采用车用动态工况,对所开发的燃料电池系统进行了6000小时以上的耐久性测试,6000小时的性能衰减率仅为8.1%.     

An investigation on the kinetics of direct carbon solid oxide fuel cells

A direct carbon solid oxide fuel cell (DC-SOFC) is an all-solid-state electricity generation device that operates directly with solid carbon as fuel, without any liquid medium and feeding gas. Tubular electrolyte-supported solid oxide fuel cells (SOFCs), with silver-gadolinium doped ceria (Ag-GDC) as both anode and cathode materials, are fabricated and operated directly with activated carbon as fuel. The kinetics of the DC-SOFCs is carried out through analyzing the correlations of the cell reaction rates to the emitting rates of CO and CO₂. It turns out that higher operating current corresponds to higher rates of consuming and producing CO, through electrochemical oxidation at the anode and the Boudouard reaction at the carbon fuel, respectively. The rate of consuming CO can be maintained constant by controlling the operating current while the rate of producing CO decreases with time because of carbon consumption. When the CO producing rate becomes smaller than the CO consuming rate, the operation will be terminated. Compared to the rates of the chemical reactions, the diffusion rates of CO and CO₂ are so fast that their impeding effect on the cell performance can be neglected.     

周期性负载变化提高乙醇燃料电池效率(英文)

We present a simple method to increase the efficiency of a direct ethanol fuel cell by a periodic modulation of the load(pulsed mode). The fuel cell was periodically short circuited with a resistor(1 Ω) for a few seconds(high load period) followed by a low load period of up to 100 s when the resistor was disconnected. The open circuit voltage(OCV) values before and after the short circuit of the cell showed an increase of up to 70 mV. The higher OCV was due to the oxidation and removal of strongly adsorbed CO during the electric short circuit when the electric potential of the anode was increased to be close to the cathode potential. The depoisoned anode surface was much more active directly after the short circuit. The slow decrease of the OCV observed after the short circuit was caused by the subsequent poisoning of the anode surface, which can be neutralized by another short circuit. In general, a stable increase in cell performance was obtained by repetition of the electric short circuit. The data showed that the pulse mode gave an increase in the power generated by the direct ethanol fuel cell by up to 51% and was 6% on average. It is anticipated that this mode of operation can be used also in different types of polymer electrolyte membrane fuel cells where CO poisoning is a problem, and after optimization of the parameters, a much higher gain in efficien-cy can be obtained.     

以活性炭为燃料的固体氧化物燃料电池(英文)

采用注浆成型法制备了管状电解质支撑的固体氧化物燃料电池(SOFC),电解质材料为YSZ,阳极和阴极材料都采用银.将活性炭不加任何气体直接用作电池的燃料.电池的有效面积为2.5cm2,在800℃时给出最大功率为16mW,其开路电压随温度的变化与理论结果一致.此电池在30mA的恒电流下连续稳定运行了37h,通过电化学反应消耗了加入电池中碳燃料的42%(w),证明了电池的工作是可以自维持的.与使用石墨燃料的SOFC相比,此电池的运行稳定性得到了明显的提高,因为活性炭比石墨具有大得多的微孔率和表面积.电池运行37h后很快衰减,燃料烧结和燃料量减少造成碳表面积减小可能是衰减的主要原因.电化学阻抗谱测试结果表明电池的极化电阻在电池的总损耗中占主导.通过对电池反应机理进行分析,认为发生在阳极/电解质界面的CO电化学氧化反应和发生在碳燃料表面的Boudouard反应构成的循环维持了电池的运行,因此通过添加促进上述两个反应的催化剂,可提高电池的性能.     

CeO2/RP-PSCFM@CoFe阳极材料用于质子导体乙烷燃料电池共生乙烯和电能

The continuous consumption and excessive use of fossil fuels promote the exploration of new energy conversion technologies. Meanwhile, the increase in the supply of ethane encourages the development of industrial technology for the production of ethylene chemical raw materials. Compared with traditional fossil fuel energy conversion equipment, solid oxide ethane cogeneration fuel cells are an efficient energy processing device. Through selective oxidation of fuel gas on the anode, the endothermic process of ethane dehydrogenation is converted into an exothermic oxidation reaction, which has a greater driving force for reaction thermodynamics, and simultaneously produces clean electricity and value-added chemicals without CO₂ emissions. The anode material used for the proton conductor ethane fuel cells needs to operate stably and efficiently under hydrocarbon fuel. Consequently, excellent catalytic activity, low polarization resistance, and anti-coking stability are essential. In this work, CeO₂ was uniformly impregnated into the surface of the porous cubic perovskite Pr_0.4Sr_0.6Co_0.2Fe_0.7Mo_0.1O_3−δ anode by wet impregnation, and then calcined and reduced to obtain a CeO₂/RP-PSCFM@CoFe composite anode embedded with nanoparticles, which was successfully used in electrolyte-supported proton conductor fuel cells. CeO₂ has a high ionic conductivity and transport capacity, which accelerates the transfer rate of protons on the anode and improves the catalytic reaction and transport process. Moreover, uniformly dispersed CeO₂ can effectively increase the three-phase interface of the anode reaction and increase the range of reaction activity. The peak power densities before and after wet impregnation reached 172 and 253 mW·cm⁻², respectively, at 750 ℃. When switching to ethane as the fuel, the peak power densities reached 136 and 183 mW·cm⁻², respectively. The polarization resistance of the impregnated single cell was significantly reduced, and the catalytic activity improved. Moreover, there was no attenuation for 10 h in the long-term test. Inversely, the current density increased with the continuous reduction of the composite anode. Product analysis revealed that the yield of ethylene increased from 23.52% at 650 ℃ to 34.09% at 750 ℃, and the ethylene selectivity exceeded 94%. These results clearly show that the impregnated anode exhibited excellent catalytic activity and anti-coking ability in hydrocarbon fuels at high temperatures. Combining CoFe nanoparticles with CeO₂ enhanced the electronic conductance and ionic conductance of the electrode, improved the transmission of electric energy and the efficient conversion of chemicals, thus successfully producing the cogeneration of electric energy and ethylene.     

直接碳固体氧化物燃料电池

碳是重要的能量载体. 直接碳固体氧化物燃料电池（DC-SOFC）是一种直接使用固体碳为燃料的能量转换装置,通过电化学反应,DC-SOFC可将碳所蕴含的化学能直接而连续地转换成电能,转换效率高,产生的CO₂浓度高,易于捕集和后续处理. 本文系统地介绍DC-SOFC的结构组成、工作原理、研究现状和发展趋势,重点介绍了作者课题组在DC-SOFC研究方面的成果和进展,包括单电池和电池组的研制、采用生物质碳和煤炭为燃料时的性能和DC-SOFC在气电联产中的应用探索.     

钙钛矿材料在固体氧化物燃料电池燃料重整中的应用

固体氧化物燃料电池（solid oxide fuel cell,SOFC）是通过电化学反应将化石燃料（煤、石油和天然气等）、生物质燃料或其它碳氢燃料中的化学能直接转换为电能的发电装置,能量转换效率更高、污染更低,被公认为21世纪高效绿色能源技术. 但直接以碳氢化合物为燃料时,镍基阳极中容易产生积碳,从而失去电化学催化活性. 在阳极外侧进行一次燃料的预重整是一种行之有效的解决办法,其中高效稳定的重整催化剂至关重要. 本文将结合本课题组的研究进展对钙钛矿催化剂在燃料重整中的应用进行概述,并提出自己相应的观点和展望.     

固体氧化物直接碳燃料电池阳极反应过程分析

以氧化钇稳定的氧化锆(YSZ)为电解质组装成直接碳燃料电池(DCFC),分别以活性炭(AC)、石墨(G)、神府半焦(SC)作为DCFC燃料,研究了碳燃料的特性、电池操作温度以及阳极反应气氛等对DCFC阳极反应过程的影响。结果表明,三种碳燃料在空气、CO₂气氛中氧化反应活性顺序为AC > SC > G,当三种碳材料作为DCFC燃料时,活性炭作为燃料的DCFC性能最好,半焦燃料次之,石墨作为燃料的DCFC性能最差,而且燃料反应活性与其表面含氧官能团、孔隙结构有关;DCFC的阳极反应过程存在碳燃料直接氧化为CO₂、CO₂与C反应转化为CO,以及CO氧化为CO₂等。     

2,4-dichlorophenol degradation by an integrated process: photoelectrocatalytic oxidation and E-Fenton oxidation

A new reactor system was designed for an integrated process involving photoelectrocatalytic oxidation (PECO) and electro-Fenton (E-Fenton) oxidation. Its efficiency was evaluated in terms of 2,4-dichlorophenol (2,4-DCP) degradation in aqueous solution. In this process, a TiO2 electrode and an iron (Fe) electrode were used as anodes in parallel, while graphite felt (GF) was used as a cathode. When an electrical current is applied between the anodes and the cathode, the iron anode can release Fe2+ and the GF cathode can generate H2O2 continuously in the reaction solution. Under UV-A illumination, while a H2O2-assisted PECO reaction occurs on the surface of the TiO2 photo anode, an E-Fenton reaction takes place in the solution. The experimental results demonstrated that 2,4-DCP degradation in aqueous solution was greatly enhanced because of the interaction between the two types of reactions. Moreover, the effect of pH as an important factor was investigated. It was found that the combined reaction becomes less pH sensitive than the typical E-Fenton reaction and may be suitable for application in a wide pH range.     

可用作便携式电源的高性能直接碳固体氧化物燃料电池组

A direct carbon solid oxide fuel cell (DC-SOFC) stack was prepared with 3 tubular cells electrically connected in series. To increase carbon storage in the stack, the anode was fabricated outside the tubular cells so that carbon fuel can be loaded at the exterior of the stack, which is more spacious than the interior. The 3-cell-stack is operated directly with carbon as the fuel and oxygen in ambient air as the oxidant. With a total effective area of 10.2 cm² and a 5% (w) Fe-loaded activated carbon fuel of 17 g, the stack reveals a peak power of 4.1 W at 800℃. The stack discharged at a constant current of 1.0 A for 19 h, giving a charge capacity of 19 A·h and an energy capacity of 31.6 W·h, which are much higher than those of a similar stack with anode on the inside and carbon loaded at the interior. The high capacity of our DC-SOFC opens up potential applications in portable devices.