与甲醇燃料电池相比,直接乙醇燃料电池具有毒性低、理论能量密度高等优点,因此被广泛认为是更有前途的未来能源器件。但是,在较低的温度下乙醇燃料电池的氧化速度较慢,这直接制约了其发展。近年来研究表明利用铂钌以及铂锡合金可以提高电池的氧化速率,其催化产物分别是CO2和双碳化合物。由于催化机理不同,在不同的电压下两种催化剂各有其优点。
最近,我国研究人员通过将两种催化剂复合成双层膜证明复合后的催化剂兼具了两种催化剂的优点。研究者分别合成了单层铂锡合金、单层铂钌合金以及含有这两种合金而顺序不同双层催化剂。结果表明,在双层催化剂中,铂锡合金与扩散层接触的催化剂具有较高活性,这是因为铂锡合金为疏水多孔结构,有利于物质的扩散。同时,双层催化剂兼具两种催化剂的优点,得到的产物表明在不同电压下分别符合两种催化剂的催化机理。
双层催化剂为乙醇燃料电池的制备提供了新的思路,从而有望提高电池的催化效率。相关论文发表在2月份的爱思唯尔期刊《电源杂志》(Journal of Power Sources)上。(科学新闻杂志 张乐生/编译)
生物谷推荐原始出处:
(Journal of Power Sources),Volume 177, Issue 1, 15 February 2008, Pages 142-147,Q. Wang,G.Q. Sun
High performance direct ethanol fuel cell with double-layered anode catalyst layer
Q. Wanga, b, G.Q. Suna, L. Caoa, b, L.H. Jianga, G.X. Wanga, S.L. Wanga, S.H. Yanga and Q. Xina
aDalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
bGraduate School of the Chinese Academy of Sciences, Beijing, 100039, China
Received 20 September 2007; revised 2 November 2007; accepted 5 November 2007. Available online 19 November 2007.
Abstract
Double-layered anode catalyst layers with two reverse configurations, which consist of 45 wt.% Pt3Sn/C and PtRu black catalyst layers, were fabricated to improve the performance of a direct ethanol fuel cell (DEFC). The in-house 45 wt.% Pt3Sn/C catalyst was characterized by XRD and TEM. The cross-sectional double-layered anode catalyst layer was observed by SEM. In DEFC performance test and anode linear sweep voltammetry measurement, the anode with double-layered catalyst layer exhibited better catalytic activity for ethanol electro-oxidation than those with single-layered 45 wt.% Pt3Sn/C and PtRu black catalyst layers. In terms of anode product distribution, the DEFC with double-layered anode catalyst layer showed a higher yield of acetic acid than that with single-layered PtRu black catalyst layer and a higher yield of CO2 than that with single-layered 45 wt.% Pt3Sn/C catalyst layer, respectively. These results suggest that the double-layered anode catalyst layer possessed the advantages of both Pt3Sn/C and PtRu black catalysts for ethanol electro-oxidation, and thus showed a higher ethanol electro-oxidation efficiency and DEFC performance in the practical polarization potential region.