直接甲酸燃料电池碳化钨载钯阳极催化剂的研究

发布时间：2018-04-06 20:31

本文选题：直接甲酸燃料电池　切入点：甲酸电氧化反应　出处：《大连理工大学》2015年硕士论文

【摘要】：直接甲酸燃料电池(Direct formic acid fuel cell, DFAFC)具有甲酸渗透率低、无毒、不易燃、运输和存储方便等优点,适用于微型电源、便携式电源等领域,近年来受到广泛关注。然而阳极甲酸电氧化反应(Formic acid electrooxidation reaction, FAOR)催化剂的活性与稳定性差阻碍了DFAFC商业化的进程。碳化钨(WC)具有独特的类Pt特性,酸性介质中稳定性良好,高比表面积、高稳定性WC将有可能利于提升催化剂活性和稳定性。针对高温碳化法制备WC易团聚、比表面积低的问题,本论文设计制备了两类高比表面积WC基载钯催化剂,通过现代谱学显微技术表征了催化剂物性,借助电化学方法评价了其对FAOR的催化活性和稳定性,主要结论如下：(1)采用模板-热解法制备了高分散Pd/WCx-T (x是指不同粒径的Si02微球模板)系列电催化剂。将不同粒径的Si02微球模板与碳源、钨源直接混合,通过高温热解制得高比表面积WCX-T,其中WCso-900比表面积404.37m2g1,高于商业化Vulcan XC-72 (250 m2 g-1);采用浸渍还原法制得Pd/WCx-T系列催化剂,20% Pd/WCio-900催化剂Pd纳米粒子均匀分布于WC10-900表面；其催化FAOR的活性大小为847.25 mA mg-1,是20% Pd/C (113.72 mA mg-1)的7.45倍；(2)以高比表面积、高导电性的石墨烯为基底,利用高温热解-模板法在其表面担载WC制备了石墨烯-碳化钨(GW)复合载体,通过浸渍还原法合成了Pd/GWy (y是指GW复合载体中WC质量分数)系列催化剂。Pd/GW20催化剂Pd纳米粒子粒径为5-9nm,均匀分散于GW复合载体表面Pd/GW2o催化剂催化FAOR的活性大小为811.5 mA mg-1,高于Pd/G (703.5 mA mg1);电位在0.1 V(vs. Ag/AgCl)下进行1800sI-t测试,Pd/GW20催化剂电流密度衰减53.4%,小于Pd/G(衰减67%); Pd/GW20催化剂电化学活性面积(ECSA)减小10%左右,小于Pd/G(减小20%-300%),表明Pd/GW20催化剂具有良好稳定性。
[Abstract]:Direct formic acid fuel cells (DFAFCs) have many advantages, such as low formic acid permeability, non-toxic, non-flammable, convenient transportation and storage.However, the poor activity and stability of Formic acid electrooxidation reaction (Faor) catalysts for anodic formic acid electrooxidation have hindered the commercialization of DFAFC.Tungsten Carbide (WCC) has unique Pt-like properties, and its stability in acid medium is good, with high specific surface area and high stability WC, which may be beneficial to enhance the activity and stability of the catalyst.Aiming at the problem of easy agglomeration and low specific surface area of WC prepared by high-temperature carbonization method, two kinds of WC supported palladium catalysts with high specific surface area were designed and prepared in this paper. The physical properties of the catalysts were characterized by modern spectroscopic microscopy.The catalytic activity and stability of FAOR were evaluated by electrochemical method. The main conclusions are as follows: (1) A series of electrocatalysts were prepared by template-pyrolysis method, which refers to the template of Si02 microspheres with different particle sizes.The template of Si02 microspheres with different diameters was mixed directly with carbon source and tungsten source.The high specific surface area of WCX-T was obtained by pyrolysis at high temperature, in which the specific surface area of WCso-900 was 404.37 m2g1, which was higher than that of commercial Vulcan XC-72 (250m2 g -1), and PD nanoparticles of 20% Pd/WCio-900 catalyst of Pd/WCx-T series were obtained by impregnation reduction method.The catalytic activity of FAOR was 847.25 Ma mg-1, 7.45 times of 20% Pd/C 113.72 mg-1). Graphene with high specific surface area and high conductivity was used as the substrate to prepare graphene and tungsten carbide GW composite carrier on its surface by high temperature pyrolysis-template method.A series of catalysts, PD / GW20, were synthesized by impregnation reduction method. The particle size of PD nanoparticles was 5-9 nm, and the activity of Pd/GW2o catalyst dispersed on the GW composite surface was 811.5.Smaller than PD / G indicates that the Pd/GW20 catalyst has good stability.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM911.4

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