Fe2N nanoparticles boosting FeNx moieties for highly efficient oxygen reduction reaction in Fe-N-C porous catalyst
Fe2N nanoparticles boosting FeNx moieties for highly efficient oxygen reduction reaction in Fe-N-C porous catalyst
复制标题
Fe_2N 纳米颗粒促进 FeN_x 部分在 Fe-N-C 多孔催化剂中实现高效氧还原反应
DOI：
10.1007/s12274-019-2415-7
复制
发表时间：
2019-07-01
期刊：
影响因子：
9.9
通讯作者：
Yang, Hui
中科院分区：
文献类型：
--
作者：
Liu, Xiao;Liu, Hong;Yang, Hui
用高性能和低成本的非贵金属催化剂取代用于氧还原反应（ORR）的Pt基电催化剂对于燃料电池的商业化至关重要。本文中，我们提出了一种高效的Fe-N-C多孔ORR电催化剂，其具有由Fe掺杂的沸石咪唑酯骨架衍生的Fe 2N纳米颗粒促进的FeN（x）部分。性能最好的Fe-N-C/HPC-NH（3）催化剂表现出上级ORR活性，起始（E-0）和半波（E-1/2）电位分别为0.945和0.803 V（RHE），这与商业Pt/C在酸性介质中的那些相当。探针实验和酸浸实验证明，FeNx基团在催化剂的氧化还原反应中起着重要作用，Fe 2N的引入可以进一步提高催化剂的氧化还原反应活性。密度泛函理论计算表明，Fe 2N的存在削弱了ORR中间体在活性位上的吸附，降低了电位限制步骤的反应自由能，从而促进了ORR的发生。Fe-N-C催化剂中Fe 2N修饰提高ORR活性的实验证据和理论分析为合理设计高性能非贵金属催化剂提供了新的思路。
Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells. Herein, we present a highly efficient Fe-N-C porous ORR electrocatalyst with FeN(x)moieties promoted by Fe2N nanoparticles derived from Fe-doped zeolitic imidazolate framework. The best-performing Fe-N-C/HPC-NH(3)catalyst exhibits a superior ORR activity with an onset (E-0) and half-wave (E-1/2) potential of 0.945 and 0.803 V (RHE), respectively, which is comparable to those of the commercial Pt/C in acidic media. Probing and acid-leaching experiments prove that FeNx moieties play an important role in the ORR and the Fe2N can further improve the ORR activity. Density functional theory calculation reveals a synergistic effect that the existence of Fe2N weakens the adsorption of ORR intermediates on active sites and lowers the reaction free energy of the potential limiting step, thus facilitating the ORR. Both experimental evidence and theoretical analysis for the enhancement of ORR activity by Fe2N decoration in Fe-N-C catalyst might inspire a new strategy for rational design of high performance non-precious metal catalysts.