活化和氮掺杂炭层包覆碳纳米管载铂催化剂电催化性能研究

摘要

Electrocatalysts of pristine carbon nanotubes (CNTs),activated CNTs from the mixed acid oxidation and nitrogen-doped carbon layer coated CNTs (NCNTs)from modification of polyaniline (PANI),loading with platinum,were prepared by using chemical reduction of immersion.The electrocatalytical performance of these platinum loaded CNTs as the catalysts of proton exchange membrane fuel cell (PEMFC)was studied.The TEM observation showed that the morphology and distribution of platinum particles onto the CNTs could be im-proved by using the activated CNTs as supports of catalyst.Particle size of platinum distributed on the activated CNTs was about 4-8 nm,but the obvious agglomeration could be observed.For the NCNTs from the modifica-tion of PANI,platinum particles with size of 2-4 nm were uniformly distributed on the NCNTs surface owing to the uniform nitrogen doped layer coated on the CNTs.Electrochemical analyses showed that both the activation and nitrogen doping on the CNTs could improve the activity of catalysts supported on CNTs,especially that platinum loaded NCNTs not only possess the best activity of oxygen reduction but also exhibited a good cycling stability.%利用化学浸渍还原法,以原始和混酸活化碳纳米管及聚苯胺改性制备的氮掺杂炭层包覆碳纳米管为载体,制备上述碳纳米管负载铂催化剂,研究比较它们作为质子交换膜燃料电池催化剂的电催化性能.透射电镜观察表明,以混酸活化碳纳米管为载体一定程度改善了铂粒子在碳管上的沉积形态和分散性,沉积的铂粒子大小约5~8 nm,但铂粒子仍存在较明显的团聚现象；而因聚苯胺改性碳纳米管外层为均匀氮掺杂炭层,铂粒子能均匀分散沉积于氮掺杂层表面,其平均粒径约为2~4 nm.电化学分析表明,混酸活化和氮掺杂炭层包覆碳纳米管都能够改善负载催化剂的电催化活性,尤其氮掺杂炭层包覆碳纳米管负载铂催化剂不仅具有最高氧还原活性,其负载催化剂同时展现了良好的循环稳定性.