Oxygen reduction reaction activity and long-term stability of platinum nanoparticles supported on titania and titania-carbon nanotube composites
Oxygen reduction reaction activity and long-term stability of platinum nanoparticles supported on titania and titania-carbon nanotube composites
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DOI：
10.1016/j.jpowsour.2018.08.036
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发表时间：
2018-10-01
影响因子：
9.2
通讯作者：
Behm, R. J.
中科院分区：
文献类型：
--
作者：
Eckardt, M.;Gebauer, C.;Behm, R. J.
针对用于聚合物电解质膜燃料电池（PEMFC）阴极的Pt纳米颗粒催化剂，在实际移动应用中比普通Pt/C催化剂具有高活性和更耐腐蚀性，我们制备并研究了负载在含有碳纳米管（CNT）和二氧化钛的高度稳定的纳米结构复合材料上的Pt催化剂。 TiO2@CNT 复合材料通过溶胶凝胶处理和随后的 Pt 沉积合成。通过透射电子显微镜 (TEM)、X 射线光电子能谱 (XPS)、旋转环盘电极 (RRDE) 测量和加速降解测试 (ADT) 测定这些催化剂的物理和电化学性质以及稳定性，并与商业 Pt/C、Pt/TiO2 和 Pt/CNT 进行比较。测量结果表明，复合催化剂具有与 Pt/C 催化剂相当的高活性，但在模拟启停行为的 ADT 过程中 ORR 活性几乎完全丧失。与碳负载催化剂相比，碳负载催化剂的降解主要与高电势下的腐蚀有关，我们发现二氧化钛负载催化剂主要遭受 ADT 中的还原处理。讨论了在燃料电池应用中使用负载在可还原氧化物（例如 TiO2）上的 Pt 催化剂作为阴极催化剂的后果。
Aiming at Pt nanoparticle catalysts for application in polymer electrolyte membrane fuel cell (PEMFC) cathodes, which are highly active and more corrosion resistant under realistic mobile applications than common Pt/C catalysts, we have prepared and investigated Pt catalysts supported on highly stable, nanostructured composite materials containing carbon nanotubes (CNTs) and titania. TiO2@CNT composite materials are synthesized via sol-gel processing and subsequent Pt deposition. The physical and electrochemical properties as well as the stability of these catalysts, as determined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), rotating ring disk electrode (RRDE) measurements and accelerated degradation tests (ADTs), were compared with those of commercial Pt/C, Pt/TiO2 and Pt/CNT. The measurements reveal a high activity of the composite catalyst, comparable to that of the Pt/C catalyst, but an almost complete loss of ORR activity upon an ADT procedure simulating start-stop behavior. In contrast to carbon supported catalysts, where degradation is mainly associated with corrosion at high potentials, we find the titania supported catalysts to mainly suffer from the reductive treatment in the ADTs. Consequences for the use of Pt catalysts supported on reducible oxides such as TiO2 as cathode catalysts in fuel cell applications are discussed.