Defect-Free Encapsulation of Fe0 in 2D Fused Organic Networks as a Durable Oxygen Reduction Electrocatalyst
Defect-Free Encapsulation of Fe0 in 2D Fused Organic Networks as a Durable Oxygen Reduction Electrocatalyst
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DOI：
10.1021/jacs.7b10663
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发表时间：
2018-02-07
影响因子：
15
通讯作者：
Baek, Jong-Beom
中科院分区：
文献类型：
--
作者：
Kim, Seok-Jin;Mahmood, Javeed;Baek, Jong-Beom
由于它们成本较低，但活性与贵金属铂 (Pt) 基催化剂相当，非贵金属铁 (Fe) 基材料，如 Fe/Fe3C 和 Fe-N-C，作为氧还原反应 (ORR) 的电催化剂而受到广泛关注。然而，它们的实际应用因其稳定性差而受到阻碍，这归因于极不稳定的铁纳米粒子的保护缺陷。在这里，我们介绍了一种稳定的铁基电催化剂的合成策略，该策略是通过使用二维（2D）吩嗪基稠合芳香族多孔有机网络（Aza-PON）对铁纳米颗粒进行无缺陷封装来实现的。所得的 Fe@Aza-PON 催化剂表现出电催化活性（半波电位，0.839 V；塔菲尔斜率，60 mV decade(-1)），与商业活性炭上的 Pt（Pt/C，0.826 V 和 90 mV decade-1）相当。更重要的是，Fe@Aza-PON 显示出出色的稳定性（即使在 100 000 次循环后也为零电流损耗）和对污染（甲醇和 CO 中毒）的耐受性。在混合锂空气电池测试中，Fe@Aza-PON 表现出优于 Pt/C 的性能。
Because they provide lower cost but comparable activity to precious platinum (Pt)-based catalysts, nonprecious iron (Fe)-based materials, such as Fe/Fe3C and Fe-N-C, have gained considerable attention as electrocatalysts for the oxygen reduction reaction (ORR). However, their practical application is hindered by their poor stability, which is attributed to the defective protection of extremely unstable Fe nanoparticles. Here, we introduce a synthesis strategy for a stable Fe-based electrocatalyst, which was realized by defect-free encapsulation of Fe nanoparticles using a two-dimensional (2D) phenazine-based fused aromatic porous organic network (Aza-PON). The resulting Fe@Aza-PON catalyst showed electrocatalytic activity (half-wave potential, 0.839 V; Tafel slope, 60 mV decade(-1)) comparable to commercial Pt on activated carbon (Pt/C, 0.826 V and 90 mV decade-1). More importantly, the Fe@Aza-PON displayed outstanding stability (zero current loss even after 100 000 cycles) and tolerance against contamination (methanol and CO poisoning). In a hybrid Li-air battery test, the Fe@Aza-PON demonstrated performance superior to Pt/C.