1成果简介
　　要延长质子交换膜燃料电池的使用寿命，就必须开发高度耐用的铂基阴极催化剂。虽然已经确定了阴极催化剂的两种降解途径--碳腐蚀和电催化剂（铂纳米颗粒）粗化，但目前提高其耐用性的方法仅限于解决个别降解途径。本文，中国科学技术大学童磊（特任副研究员）、梁海伟 教授、江西师范大学Hai-Wei Liang等研究人员在“Core/Shell-Structured Carbon Support Boosting Fuel Cell Durability”的论文，研究开发了一种核/壳结构碳载体，旨在提供能够同时抑制碳腐蚀和电催化剂粗化的阴极催化剂。
　　这种核/壳结构具有双功能特性：核由高度石墨化的碳制成，旨在构建坚固的碳骨架；壳由掺杂杂原子的无定形碳组成，旨在通过化学/物理锚定铂纳米粒子来防止电催化剂粗化。得益于这一精心设计，该催化剂超越了美国能源部为碳支撑和电催化剂设定的耐用性目标，方波/三角波加速应力测试后达到的耐用性指标也证明了这一点：电化学表面积损失为 13%/3%，质量活性损失为 27%/17%，电压损失为29mV（0.8 A cm-2）/4 mV（1.5A cm-2）。
　　2图文导读 

　　图1、Schematic illustration of the deactivation mechanism for the a) Pt/GC, b) Pt/PC, and c) Pt/cs-C catalysts upon the electrocatalyst or carbon support durability tests.

　　图2、Characterizations of the catalysts. a–c) TEM images of Pt/PC (a), Pt/GC (b), and Pt/cs-C (c). The insets represent the particle size distribution histograms. d) High-resolution STEM images of Pt/cs-C. e) EDS mapping images of Pt/cs-C.

　　图3、TW AST. a–c) H2-air polarization curves of Pt/PC (a), Pt/GC (b), and Pt/cs-C (c), at BOL and TW-EOL. d–f) Histograms of voltage loss at 1.5 A cm−2 (d), ECSA loss (e), and MA loss (f) of Pt/PC, Pt/GC, and Pt/cs-C after TW AST.

　　图4、SW AST. a–c) H2-air polarization curves of Pt/PC (a), Pt/GC (b), and Pt/cs-C (c), at BOL and SW-EOL. d–f) Histograms of voltage loss at 0.8 A cm−2 (d), ECSA loss (e), and MA loss (f) of Pt/PC, Pt/GC, and Pt/cs-C after SW AST.

　　图5、Combined SW+TW AST and TW+SW AST. a,b) Protocols of the continuous “SW+TW AST” (a) and “TW+SW AST” (b). c,d) H2-air polarization curves of Pt/cs-C before and after “SW+TW AST” (c) and “TW+SW AST” (d). e,f) Histograms of voltage loss (e) and ECSA loss (f) after the two continuous AST protocols.

　　图6、Electrochemical diagnostics and structural characterizations after the durability tests. a) CCL thickness of Pt/PC, Pt/GC, and Pt/cs-C at BOL, TW-EOL, and SW-EOL. b,c) Contrast-rendered cross-sectional SEM images of Pt/PC CCL at BOL (b) and TW-EOL (c), wherein the red and gray-marked regions represent pore and carbon support, respectively. d) Average particle sizes of Pt/PC, Pt/GC, and Pt/cs-C at BOL, TW-EOL, and SW-EOL. e,f) Proton resistivity (e) and total O2 transportation resistance (f) of Pt/PC, Pt/GC, and Pt/cs-C at BOL, TW-EOL, and SW-EOL.
　　3小结
　　总之，我们通过设计以石墨化碳芯和掺杂杂原子的无定形碳壳为特征的碳载体，开发出了既能抗碳腐蚀又能抗电催化剂粗化的燃料电池阴极催化剂。基于全面的表征和MEA诊断，我们证实石墨化碳核为催化剂提供了一个坚固的框架，能够最大限度地减少碳腐蚀造成的损害，而掺杂杂原子的无定形碳壳在抑制电催化剂粗化方面的关键作用来自于其通过物理限制/化学结合锚定铂纳米粒子的能力。考虑到实际应用中对功率密度的要求，以及本研究中强调的GC框架在提高耐久性方面的关键作用，我们认为开发具有高比表面积的石墨碳载体是实现高性能和高耐久性的可行途径之一。
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