聚苯胺掺杂对燃料电池阳极催化剂载体性能的促进作用

发布时间：2018-08-22 17:53

【摘要】：近年来,导电高分子材料由于具有共轭的电子结构,良好的导电性和稳定性,已经越来越多地在电催化剂载体方面广泛应用。其中,聚苯胺的主链上含有交替的氮原子和苯环,具有优良的环境稳定性和导电性。聚苯胺修饰活性碳制备出的聚苯胺碳复合载体,可以较大幅度的提高载体的导电性和稳定性。本文利用化学氧化聚合法制备了聚苯胺碳复合载体(PAnC);选用十二烷基磺酸钠(SDS)和十二烷基苯磺酸钠(SDBS)掺杂剂对复合载体PAnC进行掺杂,并研究了掺杂剂的用量对聚苯胺碳载体性能的影响;以掺杂的聚苯胺碳复合载体分别制备聚苯胺碳载钯、钯金催化剂。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线衍射(XRD)、比表面积(BET)和电化学表面积(ESA)对载体和催化剂进行了物理表征;采用循环伏安法(CV)、计时电流法(CA)和交流阻抗法(EIS)等测试技术对所制备的催化剂进行电化学性能研究。此外,还研究了不同方法制备的聚苯胺碳载铂催化剂对甲醇、乙醇电催化氧化性能的影响。对单一的活性碳载体和掺杂后的聚苯胺碳复合载体分别进行物理表征的结果发现,PAnC粒子呈圆球形,颗粒大小均匀,粒径大小均在30 nm左右。掺杂后的PAnC载体具有更低的电荷传递电阻,提高了载体的导电性;10?25 nm的介孔数量明显增加,有效比表面积明显增大。透射电镜结果表明,与聚苯胺碳载钯催化剂相比,聚苯胺碳载钯金催化剂中颗粒粒径更小,金属颗粒在载体表面分散得更加均匀。电化学研究结果表明,分别用掺杂0.2 g十二烷基磺酸钠和0.05 g十二烷基苯磺酸钠的聚苯胺载体制备的钯或钯金催化剂对甲酸具有最高的活性和稳定性,从而确定了最佳掺杂量。相同条件下,聚苯胺碳载钯金催化剂对甲酸的电催化氧化性能比聚苯胺碳载钯催化剂好。用不同方法制备的铂催化剂对甲醇和乙醇的电催化氧化性能研究结果表明,与热还原法相比,用微波法制备的聚苯胺碳载铂催化剂对甲醇、乙醇的电催化氧化性能更好。
[Abstract]:In recent years, conductive polymer materials with conjugated electronic structure, good conductivity and stability have been widely used in electrocatalyst support. Among them, the main chain of Polyaniline contains alternating nitrogen atom and benzene ring, which has excellent environmental stability and electrical conductivity. Polyaniline carbon composite carrier modified with Polyaniline can improve the conductivity and stability of the support. In this paper, Polyaniline carbon composite carrier (PAnC); was prepared by chemical oxidation polymerization. The dopant of sodium dodecyl sulfonate (SDS) and sodium dodecylbenzene sulfonate (SDBS) was used to doping the composite carrier PAnC. The influence of the amount of dopant on the performance of Polyaniline carbon support was studied, and the carbon supported palladium and palladium gold catalysts were prepared by doping Polyaniline carbon composite support. The support and catalyst were physically characterized by scanning electron microscope (SEM), (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD),) specific surface area (BET) and electrochemical surface area (ESA). The electrochemical properties of the catalysts were studied by cyclic voltammetry (CV),) chronoamperometric method (CA) and AC impedance method (EIS). In addition, the effect of Polyaniline carbon supported platinum catalysts prepared by different methods on the electrocatalytic oxidation of methanol and ethanol was studied. The results of physical characterization of the single active carbon support and the doped Polyaniline carbon composite support show that the PAnC particles are spherical, the particle size is uniform, and the particle size is about 30 nm. The doped PAnC carrier has lower charge transfer resistance, which improves the conductivity of the carrier and increases the number of mesoporous cells at 1025 nm and the effective specific surface area. The results of transmission electron microscope showed that the particle size of the catalyst was smaller and the metal particles dispersed more evenly on the surface of the support than that of the pani carbon-supported palladium catalyst. The electrochemical results showed that the palladium or palladium gold catalyst prepared by the support of Polyaniline doped with 0.2 g sodium dodecyl sulfonate and 0.05 g sodium dodecyl benzene sulfonate had the highest activity and stability to formic acid, and the optimum doping amount was determined. Under the same conditions, the electrocatalytic oxidation performance of Polyaniline carbon supported palladium gold catalyst for formic acid is better than that of Polyaniline carbon supported palladium catalyst. The electrocatalytic oxidation of methanol and ethanol over platinum catalysts prepared by different methods was studied. The results showed that compared with the thermal reduction method, the electrocatalytic oxidation of methanol and ethanol was better than that of the carbon supported platinum catalyst prepared by microwave method.
【学位授予单位】：哈尔滨师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TM911.4

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