Electrochemistry Laboratory, Paul Scherrer Institut, 5232, Villigen, Switzerland.
Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4 Takeda, Kofu, 400-8511, Japan.
Angew Chem Int Ed Engl. 2017 Aug 28;56(36):10707-10710. doi: 10.1002/anie.201704253. Epub 2017 Jul 18.
Highly active and durable oxygen reduction catalysts are needed to reduce the costs and enhance the service life of polymer electrolyte fuel cells (PEFCs). This can be accomplished by alloying Pt with a transition metal (for example Ni) and by eliminating the corrodible, carbon-based catalyst support. However, materials combining both approaches have seldom been implemented in PEFC cathodes. In this work, an unsupported Pt-Ni alloy nanochain ensemble (aerogel) demonstrates high current PEFC performance commensurate with that of a carbon-supported benchmark (Pt/C) following optimization of the aerogel's catalyst layer (CL) structure. The latter is accomplished using a soluble filler to shift the CL's pore size distribution towards larger pores which improves reactant and product transport. Chiefly, the optimized PEFC aerogel cathodes display a circa 2.5-fold larger surface-specific ORR activity than Pt/C and maintain 90 % of the initial activity after an accelerated stress test (vs. 40 % for Pt/C).
需要高效且耐用的氧还原催化剂来降低聚合物电解质燃料电池 (PEFC) 的成本并延长其使用寿命。通过将铂与过渡金属（例如镍）合金化并消除易腐蚀的基于碳的催化剂载体，可以实现这一目标。然而，将这两种方法结合起来的材料很少应用于 PEFC 阴极中。在这项工作中，一种无载体的 Pt-Ni 合金纳米链集合体（气凝胶）展示了与碳载基准（Pt/C）相当的高电流 PEFC 性能，这是通过优化气凝胶的催化剂层 (CL) 结构实现的。后者是通过使用可溶性填充剂将 CL 的孔径分布移向更大的孔来实现的，从而改善了反应物和产物的传输。主要的是，优化后的 PEFC 气凝胶阴极的比表面积 ORR 活性比 Pt/C 大约 2.5 倍，并且在加速应力测试后保持初始活性的 90%（而 Pt/C 为 40%）。
