Atomically dispersed Fe-N-C decorated with Pt-alloy core-shell nanoparticles for improved activity and durability towards oxygen reduction
Atomically dispersed Fe-N-C decorated with Pt-alloy core-shell nanoparticles for improved activity and durability towards oxygen reduction
复制标题
原子分散Fe-N-C修饰的pt合金核壳纳米颗粒，提高氧还原活性和耐久性
DOI：
10.1039/d0ee00832j
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发表时间：
2020-09-01
影响因子：
32.5
通讯作者：
Liu, Meilin
中科院分区：
文献类型：
--
作者：
Ao, Xiang;Zhang, Wei;Liu, Meilin
阻碍质子交换膜燃料电池广泛商业化的关键挑战之一是氧还原反应(ORR)催化剂的高成本和性能不足。在这里，我们报道了一种由有序的金属间化合物铂合金纳米颗粒附着在具有原子分散的Fe-N-C位的N掺杂的碳衬底上的复合ORR催化剂，表现出显著增强的催化活性和耐久性，获得了0.923 V的半波电位(vs.RHE)，并且在5000次加速耐久性测试后活性损失可以忽略不计。该复合催化剂是通过在氮掺杂的碳衬底上沉积纳米铂颗粒和随后的热处理而制备的，其中铁氮碳原子分散在金属-有机骨架上。后者形成了以有序的金属间化合物Pt3M(M=Fe和Zn)为核心，在壳层表面有铂原子的核壳结构的铂合金纳米粒子，这有利于ORR的活性和稳定性。Fe在多孔Fe-N-C载体中的存在不仅为ORR提供了更多的活性中心，而且有效地提高了复合催化剂的耐久性。实验测量和计算分析证实，观察到的性能提高主要归因于复合催化剂的独特结构。此外，使用所开发的ORR催化剂构建的燃料电池的峰值功率密度为1.31W cm(-2)。本文提出的策略也适用于其他电催化反应的复合催化剂的开发。
One of the key challenges that hinders broad commercialization of proton exchange membrane fuel cells is the high cost and inadequate performance of the catalysts for the oxygen reduction reaction (ORR). Here we report a composite ORR catalyst consisting of ordered intermetallic Pt-alloy nanoparticles attached to an N-doped carbon substrate with atomically dispersed Fe-N-C sites, demonstrating substantially enhanced catalytic activity and durability, achieving a half-wave potential of 0.923 V (vs. RHE) and negligible activity loss after 5000 cycles of an accelerated durability test. The composite catalyst is prepared by deposition of Pt nanoparticles on an N-doped carbon substrate with atomically dispersed Fe-N-C sites derived from a metal-organic framework and subsequent thermal treatment. The latter results in the formation of core-shell structured Pt-alloy nanoparticles with ordered intermetallic Pt3M (M = Fe and Zn) as the core and Pt atoms on the shell surface, which is beneficial to both the ORR activity and stability. The presence of Fe in the porous Fe-N-C substrate not only provides more active sites for the ORR but also effectively enhances the durability of the composite catalyst. The observed enhancement in performance is attributed mainly to the unique structure of the composite catalyst, as confirmed by experimental measurements and computational analyses. Furthermore, a fuel cell constructed using the as-developed ORR catalyst demonstrates a peak power density of 1.31 W cm(-2). The strategy developed in this work is applicable to the development of composite catalysts for other electrocatalytic reactions.