共查询到18条相似文献,搜索用时 218 毫秒
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直接尿素燃料电池可同时处理含尿素废水(尿液等)并发电,且Ni基材料为阳极尿素电氧化反应的有效催化剂。然而由于尿素电氧化反应复杂且缓慢的动力学使得Ni基催化剂活性低且稳定性差,导致直接尿素燃料电池功率密度普遍较低。实现其应用的关键在于对Ni基催化剂进行改性以构建高效稳定的催化剂层及其膜电极组件。因此,详细评述了组装成直接尿素燃料电池的阳极催化剂研究进展,深入分析改性后的催化剂组成结构对系统性能的影响机制(包括载体效应和协同效应),旨在为设计高效稳定的尿素电氧化催化剂提供科学依据。此外,阐述了直接尿素燃料电池系统中膜材料的研究现状及其膜电极组件的构建。最后,总结并展望了该领域的研究重点及未来研究的发展方向,为开发高性能直接尿素燃料电池以推进其商业化进程提供借鉴。 相似文献
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《化工学报》2017,(5)
硼氢化物水解是导致直接硼氢化物燃料电池(DBFC)燃料效率下降的主要问题之一。将Co_3O_4用于DBFC阳极催化剂并通过镀银处理以降低水解反应。以CoCl_2·6H_2O为原料制备Co_3O_4,并通过银镜反应对其进行镀银处理,制得Co_3O_4@Ag。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱(EDS)对其进行物理表征,通过交流阻抗(EIS)、计时电流(CA)和电池测试对其电化学性能进行表征。结果表明,利用银镜反应成功地将Ag引入到催化剂体系,且Co_3O_4@Ag催化材料的含银量为2%。电化学测试表明,与Co_3O_4相比Co_3O_4@Ag具有更高的电催化活性。以Co_3O_4@Ag为阳极催化剂组装的燃料电池在室温下最大功率密度(55 m W·cm~(-2))和比容量(971 m A·h·g~(-1))较Co_3O_4分别提高了44.7%和32.1%,阳极催化剂性能得到显著提高。Ag在抑制水解反应的同时与Co_3O_4体现了协同催化的作用。 相似文献
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利用水热法,以聚乙二醇为还原剂将硝酸银还原, 产生的金属银颗粒直接沉积于钛表面,制备出具有三维网状结构的新型钛基银电极 (Ag/Ti)。利用循环伏安(CV)技术研究了碱性溶液中,Ag/Ti对硼氢化钠氧化的电催化活性。结果表明,硼氢化物在Ag/Ti电极上的氧化属直接电化学氧化过程,Ag/Ti电极对硼氢化物的电化学氧化表现出极高的电流密度,并且硼氢化物氧化的起始电位较低,约为-0.64 V vs SCE,说明Ag/Ti电极对硼氢化物氧化具有高度的电催化活性,有望作为硼氢化物燃料电池的阳极材料而得到应用。 相似文献
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甲醇的电催化氧化是直接甲醇燃料电池的核心反应,高效、长寿命的阳极催化剂的开发是直接甲醇燃料电池研究的一个重要方向。本文总结了近年来酸性环境中直接甲醇燃料电池阳极催化剂的研究进展,包括甲醇电催化反应机理、催化剂的设计合成及其应用。重点介绍了铂基催化剂纳米材料活性和稳定性的增强策略,如组分调控、形貌调控、非金属掺杂以及氧化物的协同催化、载体材料的选用等。最后,对阳极催化剂目前仍存在的制备成本高、催化剂耐久性不足、表征技术有限等问题进行了分析讨论,并对阳极催化剂未来的发展方向进行了展望。 相似文献
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硼氢化物水解是导致直接硼氢化物燃料电池(DBFC)燃料效率下降的主要问题之一。将Co3O4用于DBFC阳极催化剂并通过镀银处理以降低水解反应。以CoCl2·6H2O为原料制备Co3O4,并通过银镜反应对其进行镀银处理,制得Co3O4@Ag。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱(EDS)对其进行物理表征,通过交流阻抗(EIS)、计时电流(CA)和电池测试对其电化学性能进行表征。结果表明,利用银镜反应成功地将Ag引入到催化剂体系,且Co3O4@Ag催化材料的含银量为2%。电化学测试表明,与Co3O4相比Co3O4@Ag具有更高的电催化活性。以Co3O4@Ag为阳极催化剂组装的燃料电池在室温下最大功率密度(55 mW·cm-2)和比容量(971 mA·h·g-1)较Co3O4分别提高了44.7%和32.1%,阳极催化剂性能得到显著提高。Ag在抑制水解反应的同时与Co3O4体现了协同催化的作用。 相似文献
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碱性燃料电池性能较稳定,催化剂的选择不受贵金属的限制。其中,阳极催化剂对加速燃料的氧化反应速率、碱性燃料电池的能效、稳定性和成本都有很大的影响。该文从碱性燃料电池阳极催化剂种类、载体和制备方法等方面对近年来阳极催化剂的研究现状进行了分析。分析结果表明,掺杂不同金属的合金催化剂有效提高了催化剂的电催化活性;催化剂载体种类、负载量和分散度的不同影响催化剂的稳定性;金属氧化物的加入可以同时提高催化剂的电催化活性和稳定性;催化剂制备方法的改进可以提高催化剂电化学比表面积,改变元素的分布。 相似文献
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A direct borohydride fuel cell (DBFC) employing a polyvinyl alcohol (PVA) hydrogel membrane and a nickel‐based composite anode is reported. Carbon‐supported platinum and sputtered gold have been employed as cathode catalysts. Oxygen, air and acidified hydrogen peroxide have been used as oxidants in the DBFC. Performance of the PVA hydrogel membrane‐based DBFC was tested at different temperatures and compared with similar DBFCs employing Nafion® membrane electrolytes under identical conditions. The borohydride–oxygen fuel cell employing PVA hydrogel membrane yielded a maximum peak power density of 242 mW cm–2 at 60 °C. The peak power densities of the PVA hydrogel membrane‐based DBFCs were comparable or a little higher than those using Nafion® 212 membranes at 60 °C. The fuel efficiency of borohydride–oxygen fuel cell based on PVA hydrogel membrane and Ni‐based composite anode was found to be between 32 and 41%. The cell was operated for more than 100 h and its performance stability was recorded. 相似文献
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We investigate the performance of air-breathing laminar flow-based fuel cells (LFFCs) operated with five different fuels (formic acid, methanol, ethanol, hydrazine, and sodium borohydride) in either acidic or alkaline media. The membraneless LFFC architecture enables interchangeable operation with different fuel and media combinations that are only limited by the actual anode catalyst used. Furthermore, operating under alkaline conditions significantly improves methanol and ethanol oxidation kinetics and stabilizes sodium borohydride. LFFCs operated with hydrazine and sodium borohydride as fuels exhibit power densities of 80 and 101 mW/cm2, respectively. To optimize anode performance, particularly for ethanol electro-oxidation, we introduced a hydrogen cathode to the membraneless LFFC design which renders the cell an ideal platform for anode investigation. Here, we highlight two simple diagnostic methods, in situ single electrode studies and electrochemical impedance spectroscopy (EIS), for characterizing and optimizing the performance of a direct ethanol LFFC anode. 相似文献
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The direct borohydride fuel cell (DBFC) has attracted increasing interest as a potential high power source for mobile and portable applications. Engineering design plays an important role in the development of the DBFC. This paper reports data for the selection of anode, cathode, and membrane materials for the DBFC. The best DBFC performance is achieved with a Au anode, a Pt cathode, and a 3541P ion exchange membrane. The use of non‐precious catalysts, e.g., Ag, leads to promising results. 相似文献
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Marian Chatenet 《Electrochimica acta》2006,51(25):5459-5467
The direct oxidation of sodium borohydride in concentrated sodium hydroxide medium has been studied by cyclic and linear voltammetry, chronoamperometry and chronopotentiometry for silver and gold electrocatalysts, either bulk and polycrystalline or nanodispersed over high area carbon blacks. Gold and silver yield rather complete utilisation of the reducer: around 7.5 electrons are delivered on these materials, versus 4 at the most for platinum as a result of the BH4− non-negligible hydrolysis taking place on this latter material. The kinetic parameters for the direct borohydride oxidation are better for gold than for silver. A strong influence of the ratio of sodium hydroxide versus sodium borohydride is found: whereas the theoretical stoichiometry does forecast that eight hydroxide ions are needed for each borohydride ion, our experimental results prove that a larger excess hydroxide ion is necessary in quasi-steady state conditions. When the above-mentioned ratio is unity (1 M NaOH and 1 M NaBH4), the tetrahydroborate ions direct oxidation is limited by the hydroxide concentration, and their hydrolysis is no longer negligible. The hydrolysis products are probably BH3OH− ions, for which gold displays a rather good oxidation activity. Additionally, silver, which is a weak BH4− oxidation electrocatalyst, exhibits the best activity of all the studied materials towards the BH3OH− direct oxidation.Finally, carbon-supported gold nanoparticles seem promising as anode material to be used in direct borohydride fuel cells. 相似文献
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Ü.B. Demirci 《Electrochimica acta》2007,52(15):5119-5121
The present discussion paper deals with the Gyenge's [E. Gyenge, Electrochim. Acta 49 (2004) 965] suggestion to add thiourea (H2N-CS-NH2) to the borohydride fuel of the direct borohydride fuel cell (DBFC). It is expected that thiourea inhibits the hydrogen evolution (stem from the borohydride hydrolysis, a side reaction) that occurs at the anode of the DBFC where in fact it is expected the direct oxidation of borohydride.However, thiourea is an organic sulphur compound and it is well known that the sulphur species are poisons for the metallic catalysts. Hence, the present discussion paper asks a question: may thiourea and the sulphur species stem from its decomposition act as poisons of metallic sites of catalysts used as DBFC anodes? 相似文献
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Electrocatalysts for the anodic oxidation of borohydrides 总被引:1,自引:0,他引:1
Anodic performances of alkali borohydrides on several electrocatalysts such as Ni, Raney Ni, Pd, Pt, Cu, Au have been studied in an effort to develop suitable electrode materials for a borohydride-fueled fuel cell. The open-circuit potentials (OCPs), polarization performances, and hydrogen evolution behaviors were examined in a three-electrode system. The open-circuit potential was found to be dependent on borohydride concentration and also influenced by the electrocatalyst. In concentrated borohydride solutions used in this work, electrode polarizations were less influenced by the fuel concentration. Borohydrides on different electrocatalysts showed different hydrogen evolution behaviors. The relation of hydrogen evolution rate with the anode current was found to change not only with the concentration of borohydride and but also with the electrode material. Comparison of anodic behaviors of borohydride on different electrodes implies that the anodic oxidation of borohydride, as a multi-step process, may take different reaction paths, depending on the electrocatalyst and reaction conditions such as the borohydride concentration. 相似文献
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Our study explores the use of porous carbon as anode catalyst support to improve borohydride utilization in a direct borohydride fuel cell. Pt catalysts supported by carbon aerogel (CA) and macroporous carbon (MPC) are synthesized by template method. The pores in porous carbon materials catch hydrogen bubbles to regulate the contact of anolyte with catalytic sites, and this leads to the depression of hydrogen evolution during BH4− electrooxidation. However, the hydrogen bubbles in the pores simultaneously deteriorate charge carrier transport and thus increase anode polarization. The CA‐supported Pt catalyst improves the coulombic efficiency of BH4− electrooxidation. However, the MPC‐supported Pt catalyst performed better than the CA‐supported Pt catalyst. MPC also has a good pore distribution, which improves the coulombic efficiency of BH4− electrooxidation without decreasing anode performance. 相似文献
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N. Duteanu G. Vlachogiannopoulos M. R. Shivhare E. H. Yu Keith Scott 《Journal of Applied Electrochemistry》2007,37(9):1085-1091
Data on the performance of a direct borohydride fuel cell (DBFC) equipped with an anion exchange membrane, a Pt–Ru/C anode
and a Pt/C cathode are reported. The effect of oxidant (air or oxygen), borohydride and electrolyte concentrations, temperature
and anode solution flow rate is described. The DBFC gives power densities of 200 and 145 mW cm−2 using ambient oxygen and air cathodes respectively at medium temperatures (60 °C). The performance of the DBFC is very good
at low temperatures (ca. 30 °C) using modest catalyst loadings of 1 mg cm−2 for anode and cathode. Preliminary data indicate that the cell will be stable over significant operating times. 相似文献