面向直接醇类燃料电池应用的铂基和钯基空心催化剂的研究进展

直接醇类燃料电池具有广阔的应用前景。而铂基和钯基贵金属催化剂的使用使得其成本较高,无法大规模商业化应用。将催化剂设计成空心结构是提高贵金属使用率降低贵金属用量的有效办法。本文综述了面向直接醇类燃料电池应用的铂基和钯基空心催化剂的制备方法,包括模板法、置换反应法和无模板法。     

质子交换膜燃料电池研究进展

介绍了燃料电池的工作原理及目前世界上主要燃料电池的主要特性;综述了质子交换膜燃料电池(PEMFC)的主要基础研究进展;简单介绍了PEMFC关键部件的研究方向。     

直接尿素燃料电池研究进展

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。     

直接甲醇燃料电池研究进展

介绍了直接甲醇燃料电池的工作原理、研究现状及最新进展,认为直接甲醇燃料电池是目前较理想的燃料电池,有广阔的发展前景。     

直接甲醇燃料电池技术及应用

本文回顾了直接甲醇燃料电池（ＤＭＦＣ）的研究开发历史,系统阐述了ＤＭＦＣ系统中电催化剂选择与设计基本原则、电解质膜材料与甲醇渗透的关系。分析了电池工作温度、工作压力和甲醇进料方式对ＤＭＦＣ电化学性能的影响。     

燃料电池用石墨烯基钯合金催化剂研究进展

近年来,高效、清洁电极催化剂的开发已成为人们的研究热点,石墨烯基纳米催化剂由于其出色的电催化性能和强大的协同效应而受到越来越多的关注。综述了石墨烯和石墨烯基钯合金纳米电催化剂的种类以及它们在燃料电池领域的应用,为其实际商业化生产提供了有效策略。最后指出了石墨烯基钯合金催化剂发展中面对的挑战和未来研究方向。     

直接利用生物质的化学燃料电池研究进展

近些年燃料电池技术有了长足的发展,利用燃料电池处理废弃生物质并产电是一种新型途径,可以达到废物处理、能源回收的目的。然而,受限于燃料种类、电池性能、产物分离等因素,传统的燃料电池难以直接用于处理废弃生物质。本文首先针对中低温燃料电池如碱性燃料电池、质子交换膜燃料电池的研究现状进行了综述,结果表明,碱性燃料电池在以小分子有机物作为燃料时性能良好,但是容易受到产物CO₂酸化影响;液相催化燃料电池在催化剂耐受性、生物质处理、电池功率密度等方面表现出优异的性能。然后介绍了电催化剂如过渡金属氧化物、多酸等研究现状,此类催化剂具有较强的氧化性、布朗斯特酸性和路易斯酸性等,具有很强的催化分解生物质的能力,针对液相催化剂不易分离的局限,介绍了催化剂固载化、纳米复合材料等研究进展。之后介绍了电极材料和膜材料的研究进展,碳极板因其综合性能和成本成为当前的主流选择,全氟磺酸膜性能优异,成为实验探究应用的理想材料,同时对一些复合材料的研究现状进行了简要介绍。最后,对化学燃料电池应用于生物质处理的方向进行了展望,液相催化燃料电池综合性能突出,在可处理生物质种类、催化剂循环等问题进一步优化之后,有望成为一种废弃生物质处理的新途径。     

直接甲醇燃料电池用质子交换膜的研究进展

综述了质子交换膜在直接甲醇燃料电池中的作用和要求,目前质子交换膜的研究进展,重点介绍了适用于直接甲醇燃料电池用质子交换膜的各种材料的改性方法。按照物理和化学两种方法对几类质子交换膜材料进行改性。同时对比了改性前和改性后各种聚合物膜的物性特点。     

Pd-TiO_2/C催化剂对甲酸的电催化氧化

用液相还原法制备Pd-TiO2/C催化剂。用循环伏安法(CV)和线性扫描法(LSV)考察了催化剂对甲酸的电催化氧化活性。通过计时电流曲线检测催化剂对甲酸的稳定性。结果表明Pd/TiO2/C催化剂中Pd粒子电化学比表面积增大,Pd-TiO2/C催化剂稳定,催化活性比Pd/C催化剂有较大幅度的提高。     

硫化氢固体氧化物燃料电池研究进展

综述了H2 S固体氧化物燃料电池 (SOFC)的发展历史和研制现状 ,包括固体电解质薄膜如质子传导膜和氧离子传导膜的开发、电极催化材料尤其是阳极催化材料的研制、以及整个电池系统的性能研究。指出H2 SSOFC在工业化过程中所面临和必须解决的关键技术问题是 :电解质薄膜材料的研制及其制备 ,尤其是薄膜化的制备技术 ;电极材料的开发及制备 ,特别是阳极催化材料的选择与制备技术 ;膜 -电极三合一制备技术。并对H2 SSOFC的开发及工业应用前景作了展望     

Highly effective anode structure in a direct formic acid fuel cell

We report the mass transport characteristics of formic acid and performance enhancement in a direct formic acid fuel cell in terms of the property of anode components. The effect of hydrophobicity of anode diffusion media as well as catalyst layer was investigated applying different cell temperature and fuel concentration. The operation over 80 °C and concentrated formic acid is of great advantage to the enhancement of catalytic activity and better water management. On the other hand, the conductivity of formic acid decreases by means of the formation of more complex chains of formic acid and the fuel cell resistance increases by membrane dehydration effect due to the hygroscopic property of formic acid, resulting in overall decrease of cell performance and long-term stability. Optimizing operating conditions, the use of 60% PtRu/C with only 1 mg/cm² on plain carbon paper can be one of the good choice to achieve both sustainable power performance and higher utilization of anode catalysts keeping cell resistance.     

Formic acid oxidation by carbon-supported palladium catalysts in direct formic acid fuel cell

The oxidation of formic acid by the palladium catalysts supported on carbon with high surface area was investigated. Pd/C catalysts were prepared by using the impregnation method. 30 wt% and 50 wt% Pd/C catalysts had a high BET surface area of 123.7 m²/g and 89.9 m²/g, respectively. The fuel cell performance was investigated by changing various parameters such as anode catalyst types, oxidation gases and operating temperature. Pd/C anode catalysts had a significant effect on the direct formic acid fuel cell (DFAFC) performance. DFAFC with Pd/C anode catalyst showed high open circuit potential (OCP) of about 0.84 V and high power density at room temperature. The fuel cell with 50 wt% Pd/C anode catalyst using air as an oxidant showed the maximum power density of 99 mW/cm². On the other hand, a fuel cell with 50 wt% Pd/C anode catalyst using oxygen as an oxidant showed a maximum power density of 163 mW/cm² and the maximum current density of 590 mA/cm² at 60 °C.     

Poisoning and regeneration of Pd catalyst in direct formic acid fuel cell

Palladium catalyst poisoned in the anode of direct formic acid fuel cell (DFAFC) during constant current discharging can be fully regenerated by a non-electrochemical method, i.e. just switching pure water to DFAFC for 1 h. Electrochemical impedance spectrum of DFAFC during the discharging and regeneration were recorded and analyzed. No much difference could be found for the high-frequency resistance of DFAFC after discharging while the charge transfer resistance in the mediate-frequency region increased significantly. The voltage variation during the regeneration showed that one platform of 0.35 V was formed by the intermediate species of formic acid oxidation, which is proven to be critical for cell performance regeneration. The results indicated that the absorption of poisoning species on Pd was the main reason for the decaying of cell performance.     

Preparation of Pt-Pd catalysts for direct formic acid fuel cell and their characteristics

Pt-Pd catalysts were prepared by using the spontaneous deposition method and their characteristics were analyzed in a direct formic acid fuel cell (DFAFC). Effects of calcination temperature and atmosphere on the cell performance were investigated. The calcination temperatures were 300, 400 and 500 °C and the calcination atmospheres were air and nitrogen. The fuel cell with the catalyst calcined at 400 °C showed the best cell performance of 58.8 mW/cm². The effect of calcination atmosphere on the overall performance of fuel cell was negligible. The fuel cell with catalyst calcined at air atmosphere showed high open circuit potential (OCP) of 0.812 V. Also the effects of anode and cathode catalyst loadings on the DFAFC performance using Pt-Pd (1: 1) catalyst were investigated to optimize the catalyst loading. The catalyst loading had a significant effect on the fuel cell performance. Especially, the fuel cell with anode catalyst loading of 4 mg/cm² and cathode catalyst loading of 5 mg/cm² showed the best power density of 64.7 mW/cm² at current density of 200 mA/cm². This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

Screening of PdM and PtM catalysts in a multi-anode direct formic acid fuel cell

Direct formic acid fuel cells (DFAFC) currently employ either Pt-based or Pd-based anode catalysts for oxidation of formic acid. However, improvements are needed in either the activity of Pt-based catalysts or the stability of Pd-based catalysts. In this study, a number of carbon-supported Pt-based and Pd-based catalysts, were prepared by co-depositing PdM (M = Bi, Mo, or V) on Vulcan^® XC-72 carbon black, or depositing another metal (Pb or Sn) on a Pt/C catalyst. These catalysts were systematically evaluated and compared with commercial Pd/C, PtRu/C, and Pt/C catalysts in a multi-anode DFAFC. The PtPb/C and PtSn/C catalysts were found to show significantly higher activities than the commercial Pt/C catalyst, while the PdBi/C provided higher stability than the commercial Pd/C catalyst.     

Performance characterization of direct formic acid fuel cell using porous carbon-supported palladium anode catalysts

Palladium particles supported on porous carbon of 20 and 50 nm pore diameters were prepared and applied to the direct formic acid fuel cell (DFAFC). Four different anode catalysts with Pd loading of 30 and 50 wt% were synthesized by using impregnation method and the cell performance was investigated with changing experimental variables such as anode catalyst loading, formic acid concentration, operating temperature and oxidation gas. The BET surface areas of 20 nm, 30 wt% and 20 nm, 50 wt% Pd/porous carbon anode catalysts were 135 and 90 m²/g, respectively. The electro-oxidation of formic acid was examined in terms of cell power density. Based on the same amount of palladium loading with 1.2 or 2 mg/cm², the porous carbon-supported palladium catalysts showed higher cell performance than unsupported palladium catalysts. The 20 nm, 50 wt% Pd/porous carbon anode catalyst generated the highest maximum power density of 75.8 mW/cm² at 25 °C. Also, the Pd/porous carbon anode catalyst showed less deactivation at the high formic acid concentrations. When the formic acid concentration was increased from 3 to 9 M, the maximum power density was decreased from 75.8 to 40.7 mW/cm² at 25 °C. Due to the high activity of Pd/porous carbon catalyst, the cell operating temperature has less effect on DFAFC performance.     

Performance of the direct formic acid fuel cell with electrochemically modified palladium-antimony anode catalyst

Previous work has shown that palladium catalysts are quite active for formic acid electrooxidation, but the catalysts need to be periodically regenerated to remove a CO impurity from the surface. The objective of this paper is to determine whether antimony additions could suppress the CO formation under fuel cell conditions. We find that antimony doubles the rate of reaction in an electrochemical cell, but the increase is less in real fuel cell conditions. The current that is produced at 0.6 V is approximately 14% greater for the fuel cell containing antimony additions than the palladium anode catalyst. In a constant-current test, we find that the fuel cell assembled with palladium-antimony anode catalyst produces 18% more voltage than the palladium anode catalyst after 9 h of operation. These results show that the antimony additions that significantly improve oxidation in the electrochemical cell have a much lesser impact in the formic acid fuel cell - they do not suppress CO formation in the fuel cell as anticipated.     

Carbon supported PtBi catalysts for direct formic acid fuel cells

Carbon supported PtBi bimetallic catalysts (PtBi/C) prepared by depositing Bi on a commercial Pt/C catalyst and by codeposition of Pt and Bi have been compared for formic acid oxidation in a multi-anode direct formic acid fuel cell. Both types of catalyst gave much higher cell performances than the Pt/C, with only low amounts of Bi (Pt to Bi mole ratios of 11:1 and 14:1, respectively) required for optimum performance. The high Pt to Bi ratio for the best codeposited catalyst indicates that the Bi was concentrated at the surface, and this is consistent with X-ray diffraction and X-ray photoelectron spectroscopy results. However, cyclic voltammetry revealed a strong electronic effect that is inconsistent with surface decoration. The effects of the Bi have been attributed to selective blocking of sites at which CO is formed.     

Effect of temperature, oxidant and catalyst loading on the performance of direct formic acid fuel cell

We investigated the effect of temperature, oxidant and catalyst loading on the performance of direct formic acid fuel cell (DFAFC). When oxidant was changed from air to oxygen, the power density was increased to 17.3 mW/ cm² at 25 ‡C. The power density of DFAFC operated with oxygen showed a maximum value of 40.04 mW/cm² with the temperature rise from room temperature to 70 °C. The highest power density of DFAFC using air was observed for Pt-Ru black catalyst with loading of 8 mgPt/cm² at room temperature. At 70 ‡C; however, the performance of catalyst with the loading of 4 mgPt/cm² was higher than that of 8 mgPt/cm². The DFAFC, operated with oxygen and catalyst of 4 mgPt/cm² loading, showed the best performance at all temperature range. The enhancement of cell performance with an increase of catalyst loading is believed to come from an increase of catalyst active sites. However, operated at higher temperature or with oxygen, the cell with higher catalyst loading showed lower performance than expected. It is speculated that the thick catalyst layer inhibits the proton transport.