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燃料电池具有高效、低排放等优势,非常有希望作为未来电动汽车的能源转化装置.目前,燃料电池的商业化受制于昂贵的铂基催化剂,特别是动力学迟缓的阴极氧还原反应(ORR)铂催化剂.Fe/N/C被认为是最有潜力的ORR非贵金属催化剂,但其活性仍远低于Pt催化剂,必须依靠增加载量来弥补其与Pt催化剂的活性差距.然而,较厚的催化层(~100μm)会降低阴极传质速率.因此,改善Fe/N/C阴极的传质是提高电池性能的重要途径.本文选择高N含量的2-氨基苯并咪唑(ABI)为氮源,通过水热聚合包覆在碳黑表面,然后掺入FeCl_3,经高温热解/酸洗制备了Fe/N/C-ABI催化剂,并与基于间苯二胺的微孔型Fe/N/C催化剂(Fe/N/C-Pm PDA)进行比较.Ar等温吸附-脱附结果表明,Fe/N/C-ABI催化剂具有较高的比表面积(662 m2/g)和丰富的双级孔结构(微孔和介孔);透射电镜表征显示Fe/N/C-ABI催化剂具有中空结构,介孔孔径大约为10–25 nm.而Fe/N/C-Pm PDA催化剂具有相当的比表面积(656 m2/g),但以微孔为主,基本不含介孔.旋转环圆盘电极(RRDE)测试表明,在0.1 mol/L H2SO4溶液中,Fe/N/C-ABI催化剂的起始还原电位为0.92 V,在0.8 V电位下质量电流密度可达9.21 A/g;而Fe/N/C-Pm PDA催化剂具有相近的起始电位,但具有更高的催化活性,质量电流密度为13.4 A/g.氢氧燃料电池(PEMFC)系统测试结果表明,Fe/N/C-ABI催化剂在1个背压和80 oC测试条件下的最大功率密度达710 m W/cm2,高于Fe/N/C-Pm PDA催化剂(616 m W/cm2).燃料电池与RRDE测试活性顺序的差异归结于Fe/N/C-ABI的中空球状结构.PEMFC工作时阴极会产生大量的水,很容易堵塞氧气传输通道.Fe/N/C-ABI的介孔结构可以作为水的产生和排除的缓存空间,也有利于提高O_2传质,从而提高燃料电池性能.本文为具有高传质速率的Fe/N/C催化剂研制提供了一种新思路.
Fuel cells have the advantages of high efficiency and low emission and are very promising as energy conversion devices for electric vehicles in the future.Currently, the commercialization of fuel cells is subject to expensive platinum-based catalysts, especially the slow kinetic cathodic oxygen reduction (ORR) Platinum catalyst Fe / N / C is considered as the most potential ORR non-precious metal catalyst, but its activity is still far lower than that of Pt catalyst, and it has to rely on increasing the loading to make up for the difference of its activity with Pt catalyst. The catalytic layer (~ 100μm) will decrease the mass transfer rate of the cathode, therefore improving the mass transfer of the Fe / N / C cathode is an important way to improve the performance of the battery.In this paper, 2-aminobenzimidazole (ABI) Source, Fe / N / C-ABI catalyst was prepared by hydrothermal polymerization on the surface of carbon black, then FeCl 3 was doped by high temperature pyrolysis / pickling, and was mixed with the microporous Fe / N / C catalyst (Fe / N / C-Pm PDA) .Ar isothermal adsorption-desorption results show that the Fe / N / C-ABI catalyst has a high surface area (662 m2 / g) Pore structure (micropore and mesopore); TEM characterization showed that the Fe / N / C-ABI catalyst has a hollow structure with a mesopore diameter of about 10 -25 nm, while the Fe / N / C-Pm PDA catalyst has a considerable specific surface area (656 m2 / g) but mainly micropores, with almost no mesopores. The RRDE test showed that, The initial reduction potential of Fe / N / C-ABI catalyst was 0.92 V in 0.1 mol / L H2SO4 solution, and the mass current density was 9.21 A / g at 0.8 V potential. The Fe / N / C-Pm PDA The catalyst has a similar initial potential but a higher catalytic activity with a mass current density of 13.4 A / g.PEMFC system test results show that the Fe / N / C-ABI catalyst has a higher back pressure And a maximum power density of 710 mW / cm2 over the Fe / N / C-Pm PDA catalyst (616 mW / cm2) at 80 oC. The difference in order of activity between the fuel cell and the RRDE was due to Fe / N / C-ABI hollow spherical structure .PEMFC work will produce a lot of cathode water, it is easy to plug the oxygen transmission channel .Fe / N / C-ABI mesoporous structure can be used as a buffer for the production and removal of water, there are Which will help improve the mass transfer of O2 and improve the performance of fuel cell.In this paper, a new idea for the development of Fe / N / C catalyst with high mass transfer rate is provided.