燃料电池中铁基氧还原催化剂的研究进展

阴极氧还原反应是燃料电池的核心反应之一。目前，用于氧还原反应的催化剂通常是铂基催化剂，普遍存在成本高、对甲醇耐受性差、易CO中毒等缺点，因此，开展非贵金属催化剂的研究显得尤为重要。铁基催化剂因催化活性好、稳定性高、甲醇耐受性好、价格低廉等而备受青睐，最有希望成为铂基催化剂的替代品。该文主要综述了铁基氧还原催化剂，包括含铁化合物催化剂、铁单原子催化剂、铁基合金催化剂、铁基复合物催化剂及其他铁基催化剂的研究现状、催化机理及活性影响因素，并在此基础上阐述了各类催化剂尚待解决的问题和发展方向。     

氢燃料电池阴极氧还原非金属催化剂研究进展

氧还原反应是制约氢燃料电池效率的重要因素,也是一直以来的研究热点和突破难点。非金属催化剂是近年来新兴的氧还原催化剂,对其的研究对推动燃料电池商业化具有重要意义,本文综述了近年来氧还原反应中非金属催化剂的研究进展,包括氮掺杂碳材料,硼、磷或硫掺杂碳材料,二元掺杂碳材料,最后展望了相关催化剂的未来研究趋势。     

低温燃料电池用非贵金属氧还原催化剂研究进展

非贵金属氧还原催化剂是近年来低温燃料电池最受关注的研究热点之一。本文回顾了作者课题组在低温燃料电池用非贵金属氧还原催化剂方面的研究进展,总结了提高催化活性和稳定性、降低催化剂制备成本、催化剂制备工艺和新型非贵金属氧还原催化剂设计等方面所取得的研究结果。对非贵金属氧还原催化剂亟待解决的问题和发展趋势提出自己的看法。     

金属大环化合物基氧还原电催化剂的研究进展

作为燃料电池的关键反应,阴极电极上的氧还原反应（ORR）的反应动力学缓慢,需要大量昂贵的铂基电催化剂提高反应动力学。然而,铂的价格昂贵、稀缺和耐久性差等问题严重阻碍了燃料电池系统在实际中的广泛应用。因此,发展廉价高活性的非贵金属氧还原反应催化剂是实现燃料电池商业应用关键途径之一。大环化合物基催化剂以其独特的配位结构和高共轭化学性质发展迅速,被认为是铂基材料的潜在替代品。本文总结了近年来金属大环化合物基氧还原催化剂的发展和研究成果,着重探讨了金属大环化合物基氧还原催化剂的设计和制备,并概述了金属大环化合物基氧还原催化剂面临的挑战和未来的发展方向。     

铁基纳米粒子氧还原电催化剂的研究进展

氧还原反应是锌-空气电池等能源转换器件的阴极核心反应,但受限于阴极氧还原反应迟缓的动力学过程,制约了电池的整体效率。Pt/C、RuO₂等贵金属材料是氧还原反应中普遍使用的电催化剂,由于存在成本因素、稀缺性及耐久性不佳等问题,为此寻求成本低廉、高活性、高稳定性的非贵金属基催化剂成为了当前最重要的研究目标。主要阐述了氧还原反应机理、杂原子掺杂铁基纳米粒子催化剂的研究现状,并在此基础上提出了尚待解决的问题和发展方向。     

低铂燃料电池氧还原催化剂的制备技术研究进展

低铂燃料电池催化剂铂载量低,在具有较高活性的同时能够极大地降低燃料电池的成本,因此,开发低铂燃料电池催化剂一直是燃料电池催化剂的重要研究方向。本文综述了低铂燃料电池催化剂的最新研究进展,对低铂燃料电池催化剂进行了分类,包含Pt基合金结构催化剂、Pt基核壳结构催化剂、Pt单原子层结构催化剂和Pt单原子催化剂等;详细介绍了几种低铂燃料电池催化剂的制备方法,主要包括有机溶胶法、电化学还原沉积法、气相沉积法、原子层沉积法、离子液体法、微波法,并对各自的优缺点进行了总结;重点强调了核壳结构电催化剂的制备方法,包括两步有机溶胶法、脉冲电沉积法、表面去合金化法、欠电位沉积法以及中空构型核壳结构催化剂的制备。最后指出可控制备具有高活性和高稳定性的低铂核壳结构催化剂是质子交换膜燃料电池实现商业化的重要研究方向。     

氮掺杂非贵金属氧还原催化剂研究进展

综述了近几年来用于直接甲醇燃料电池阴极氧还原反应的含氮碳催化材料发展状况,包括催化剂制备过程中热处理条件、金属的种类及负载量、碳载体、新型合成方法等影响催化剂氧还原活性的几个因素。针对当前研究工作的局限展开了评论,指出催化机理和优化制备过程是氮掺杂碳材料负载非贵金属氧还原催化剂深入研究的重点和主要方向。     

Co/Co-N-C高效氧还原催化剂的制备及其用于镁-空气燃料电池的研究

采用还原性气氛一步热解ZIF-67的方法制备钴和氮共掺杂的蓬松絮状碳纳米管Co/Co-N-C催化剂。该催化剂具有高的比表面积和良好的导电性,利用三电极体系在旋转圆盘上进行测试,结果表明,其半波电位为0.82 V,起始电位为0.93 V,表明其氧还原性能表现突出。在镁-空气燃料电池实际应用体系中进行测试,负载该催化剂的单电池最高功率密度可达60 mW/cm²,在长达20 h的恒流放电测试中,放电电压没有明显衰减,表明其具有良好的放电稳定性和应用前景。     

非贵金属氧还原电极催化剂研究进展

质子交换膜燃料电池(PEMFC)中普遍使用Pt作为阴极电催化剂,但由于Pt价格昂贵、储量稀少,PEMFC中使用大量的Pt,必然导致PEMFC制造成本的上升。因此,寻找一种能够部分或者完全达到Pt催化效果的非贵金属催化剂,成为一种可行的方法。本文对近年来非贵金属氧还原电极催化剂的研究进行了总结,特别是不同催化剂的制备方法、反应机理及活性中心进行了梳理,并对非贵金属氧还原电极催化剂的发展进行了展望。     

质子交换膜燃料电池阴极催化剂的研究进展

随着时代的发展,环境问题走进人们的视野,绿色可持续发展成了当下共同探讨的话题,而燃料电池(FC)凭借其低污染、低噪声等特点成为理想的动力源之一,质子交换膜燃料电池(PEMFC)是燃料电池的一种,具备启动速度快、电池结构简单等特点,是环保电动汽车发电技术的主要研究方向之一。其中双极板是质子交换膜燃料电池的主要部件,其上附载的催化剂决定着电池的能量转换效率、制造成本及民用价值。催化剂可分为阴极催化剂和阳极催化剂两类,本综述主要围绕阴极催化剂的开发与催化性能的研究情况,从工作原理、优缺点、催化剂及其制备、发展前景等方面进行介绍。     

Electroreduction of oxygen over iron macrocyclic catalysts for DMFC applications

The performance of macrocyclic catalysts in oxygen reduction was investigated for a direct methanol fuel cell. The dependence of catalytic activity on different factors was determined for two classes of precursors; namely, iron porphyrin (Fe-PC) and iron phthalocyanine (Fe-TPP). It was found that there was an optimal heat-treating temperature for each precursor. Heat-treated Fe-TPP shows maximum activity at 750 °C, while the highest performance in the case of Fe-PC is observed at 500 °C. It was shown that oxygen reduction activity is affected by the number of nitrogen bonds formed with iron, particle size, and formation of carbon layers.     

Nanoscale graphite-supported Pt catalysts for oxygen reduction reactions in fuel cells

The nanoscale graphite particles were prepared and the Pt catalysts supported on such graphites were developed for oxygen reduction in the polymer electrolyte membrane fuel cells. Catalytic activity and carbon corrosion of the developed catalysts were evaluated using rotating disc electrode techniques and results were compared with those of a state-of-the-art commercial E-TEK Pt catalyst supported on carbon black Vulcan XC72. The results showed that the particle distribution and the structure of the developed Pt nanoparticles supported on the nanoscale graphite were similar to those of the commercial catalyst. The accelerated degradation testing results showed that the electrochemical active surface area losses after 1500 cycles were 46.92% and 62.2% for the developed catalyst and the commercial catalyst, respectively, while mass activity losses were 45.3% and 84.2%, respectively. The temperature-programmed oxidation results suggest that the developed catalysts had better corrosion resistance than the commercial catalyst. The developed Pt catalysts had similar catalytic performance to the commercial catalyst; however, the developed catalysts had much better corrosion resistance than the commercial catalyst. Overall, nanoscale graphite can be a promising electrocatalyst support to replace the currently used Vulcan XC72 carbon black.     

铁基催化剂光催化还原CO2研究进展

利用可再生清洁能源——太阳能,将CO₂转化为一氧化碳、甲烷、甲醇等,因同时具有提供可持续燃料和解决全球变暖问题的潜力而受到越来越多的关注。铁基材料因具有金属/半导体的特性和独特的电子结构,在光催化还原CO₂领域具有广阔的应用潜力。基于此,各种具有高催化活性的铁基催化剂已经被设计来提高光催化还原CO₂的效率。概述了近年来铁基催化剂在光催化还原二氧化碳中的研究进展,对它们的结构特征和催化活性进行了阐述和比较,最后总结了铁基催化剂在光催化还原CO₂领域中待解决的问题,并展望了未来发展的方向。     

Physical and electrochemical characterization of catalysts for oxygen reduction in fuel cells

The cathode catalysts in low temperature fuel cells are associated with major cell efficiency losses, because of kinetic limitations of the oxygen reduction reaction. Additionally, methanol oxidation at the cathode leads to significant lowering of the efficiency in direct methanol fuel cells, which can be alleviated by use of methanol-tolerant catalysts. In this work, alternative carbon-supported platinum-alloy catalysts were investigated by physical methods. Second, methanol-tolerant ruthenium-selenide catalysts were characterized by physical and electrochemical methods. Besides V–i characteristics and electrochemical impedance spectroscopy as electrochemical methods, physical methods such as X-ray photoelectron spectroscopy, nitrogen adsorption, porosimetry by mercury intrusion and temperature programmed reduction are used to characterize the catalysts. The electrochemical characterization yields information about properties and behavior of the catalyst. In contrast to platinum a significantly different hydrophobic behavior of the RuSe/C catalysts is found. Low open circuit voltage values measured for RuSe/C indicate an effect on both electrodes. The anode reaction was also influenced by the different cathode catalysts. As a result of the formation of H₂O₂ at the cathode, which passes through the membrane from cathode to anode side, a mixed anode potential is formed. By comparing RuSe/C catalysts before and after electrochemical stressing, changes of the catalysts are determined. Postmortem surface analysis (by X-ray photoelectron spectroscopy) revealed that catalyst composition and MEA structure changed during electrochemical stressing. During fuel cell operation selenium oxide is removed from the surface of the catalysts to a large extent. Additionally, a segregation effect of selenium in RuSe to the surface is identified.     

Ruthenium selenide catalysts for cathodic oxygen reduction in direct methanol fuel cells

The oxygen reduction reaction in sulphuric acid on commercial carbon supported platinum and ruthenium catalysts as well as on a home-made carbon supported ruthenium selenide catalysts (RuSe _x /C) was investigated. The RuSe _x /C catalysts were synthesised using similar procedures to those found in the literature. A dependency of H₂O₂ formation on the selenium content was found using the thin-film rotating ring disc electrode technique, namely that the H₂O₂ formation in the typical operation range of a Direct Methanol Fuel Cell (0.7–0.4 V) on Pt/C is below 1% and 1–4% on Ru/C and RuSe _x /C catalysts. Finally for comparing the intrinsic activities of the catalysts the electrochemically active surface areas were determined in-situ by means of copper underpotential deposition. Our results indicate a comparable activity of the present RuSe _x /C catalyst to commercial Pt/C if the activities are related to the electrochemical active areas.     

Synthesis and characterization of Pd-Ni nanoalloy electrocatalysts for oxygen reduction reaction in fuel cells

Carbon-supported Pd-Ni nanoalloy electrocatalysts with different Pd/Ni atomic ratios have been synthesized by a modified polyol method, followed by heat treatment in a reducing atmosphere at 500-900 °C. The samples have been characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), rotating disk electrode (RDE) measurements, and single-cell proton exchange membrane fuel cell (PEMFC) tests for oxygen reduction reaction (ORR). XRD and TEM data reveal an increase in the degree of alloying and particle size with increasing heat-treatment temperature. XPS data indicate surface segregation with Pd enrichment on the surface of Pd₈₀Ni₂₀ after heat treatment at ≥500 °C, suggesting possible lattice strains in the outermost layers. Electrochemical data based on CV, RDE, and single-cell PEMFC measurement show that Pd₈₀Ni₂₀ heated at 500 °C has the highest mass catalytic activity for ORR among the Pd-Ni samples investigated, with stability and catalytic activity significantly higher than that found with Pd. With a lower cost, the Pd-Ni catalysts exhibit higher tolerance to methanol than Pt, offering an added advantage in direct methanol fuel cells (DMFC).     

Influence of carbon support on the performance of platinum based oxygen reduction catalysts in a polymer electrolyte fuel cell

Novel carbons from the Sibunit family prepared via pyrolysis of hydrocarbons [Yermakov YI, Surovikin VF, Plaksin GV, Semikolenov VA, Likholobov VA, Chuvilin AL, Bogdanov SV (1987) React Kinet Catal Lett 33:435] possess a number of attractive properties for fuel cell applications. In this work Sibunit carbons with BET surface areas ranging from ca. 20 to 420 m² g⁻¹ were used as supports for platinum and the obtained catalysts were tested as cathodes in a polymer electrolyte fuel cell. The metal loading per unit surface area of carbon support was kept constant in order to maintain similar metal dispersions (∼0.3). Full cell tests revealed a strong influence of the carbon support texture on cell performance. The highest mass specific activities at 0.85 V were achieved for the 40 and 30 wt.% Pt catalysts prepared on the basis of Sibunit carbons with BET surface areas of 415 and 292 m² g⁻¹. These exceeded the mass specific activities of conventional 20 wt.% Pt/Vulcan XC-72 catalyst by a factor of ca. 4 in oxygen and 6 in air feed. Analysis of the I–U curves revealed that the improved cell performance was related to the improved mass transport in the cathode layers. The mass transport overvoltages were found to depend strongly on the specific surface area and the texture of the support.     

直接甲醇燃料电池阳极催化剂研究进展

直接甲醇燃料电池（direct methanol fuel cells, DMFC）由于其高效、清洁等优点,成为替代化石能源的理想新能源装置。催化剂作为DMFC中重要的组成部分,通过降低反应活化能,解决甲醇需要高过电势才能被电氧化的问题。但是目前DMFC阳极催化剂存在催化活性低、抗CO毒性差以及成本较高等问题,限制了DMFC的商业化。本文介绍了甲醇的催化电氧化原理,从Pt基催化剂、非Pt基催化剂、催化剂载体三个方面对DMFC阳极催化剂国内外研究进展进行了综述。介绍了通过选择合适晶面、添加助催化剂、制备特殊形貌、选择合适的载体4种方法对提高催化剂性能、降低催化剂成本的研究现状。甲醇在Pt（100）晶面上的催化活性较好但是抗CO毒性较弱;根据双功能理论和电子调变理论,制备的Pt-M合金催化剂具有更高的抗CO毒性和甲醇催化活性;非Pt基催化剂的制备为降低催化剂成本提供了研究思路;选择合适的催化剂载体,利用载体与催化剂之间的相互作用,也成为解决DMFC阳极催化剂目前面临的易中毒、活性低、成本高等问题的解决方法。     

Ruthenium cluster-like chalcogenide as a methanol tolerant cathode catalyst in air-breathing laminar flow fuel cells

This paper reports the incorporation of a cluster-like Ru_xSe_y as a methanol tolerant cathode catalyst in a laminar flow fuel cell. The effect on cell performance of several concentrations of methanol in the cathode stream was investigated for the Ru_xSe_y catalyst and compared to a conventional platinum catalyst. While the Pt catalyst exhibited up to ∼80% drop in power density, the Ru_xSe_y catalyst showed no decrease in performance when the cathode was exposed to methanol. At several methanol concentrations the Ru_xSe_y catalyst performed better than the Pt catalyst. This demonstration of a methanol tolerant catalyst in a laminar flow fuel cell opens up the way for further miniaturization of the cell design and simplification of its operation as the need for an electrolyte stream to prevent fuel crossover has been eliminated.