华侨大学杨晓冬--中文主页-- Modeling Fe/N/C catalysts in monolayer graphene

Modeling Fe/N/C catalysts in monolayer graphene: 点击次数：; 发表刊物：ACS Catalysis; 关键字：oxygen reduction reaction iron-based catalysts monolayer graphene model catalysts active site; 摘要：Pyrolyzed Fe/N/C is one of the most promising non-precious-metal catalysts for the oxygen reduction reaction (ORR), which is supposed to boost the commercialization of proton exchange membrane fuel cells (PEMFC). However, the nature of the active sites of Fe/N/C is not clear and has long been debated. The challenges mainly come from highly heterogeneous structures formed during the pyrolysis process as well as no suitable surface probes. To elucidate the active sites, the most effective approach is building well-defined model catalysts as single-crystal planes in surface sciences. Herein, we designed a single-atomic-layer Fe/N/C model catalyst based on monolayer graphene (FeN-MLG) to explore the active sites. The model catalyst was prepared by 950 °C heat treatment of graphene with controlled defects under an FeCl3(g)/NH3 atmosphere. The as-prepared model catalyst exhibits ORR activity and SCN– suppressive effect comparable to those of normal nanoparticle-like Fe/N/C catalysts, indicating that active sites are successfully created in the model catalyst. The effect of defect density, the layer number of graphene, and nitrogen species on the ORR activity has been investigated. The main content of nitrogen species on FeN-MLG is Nx-Fe, and quantitative correlation between Nx-Fe and ORR activity demonstrates that Nx-Fe species are the active site of Fe/N/C catalysts. The proposed model catalyst serves to simplify the catalyst structures and to simulate the topmost atomic layer of normal Fe/N/C, where ORR is catalyzed. This model system opens an opportunity to further understand the highly heterogeneous Fe/N/C catalysts.; 论文类型：期刊论文; 学科门类：工学; 文献类型：J; 期号：7; 页面范围：139-145; 是否译文：否; 发表时间：2017-07-01; DOI码：10.1021/acscatal.6b02702; 第一作者：Yan-Ping Zheng,Xiao-Dong Yang; 合写作者：Xin-Xing Peng,Yu-Hao Hong,Xue Zhang,Can-Kun Zhang,Jin-Hui Zhong,Wei Shi,Jing Yang; 通讯作者：Shi-Gang Sun,Zhi-You Zhou; 发布期刊链接：https://pubs.acs.org/doi/10.1021/acscatal.6b02702

上一条： Rational Design and Synthesis of Low‑Temperature Fuel Cell Electrocatalysts

下一条： A mesoporous Fe/N/C ORR catalyst for polymer electrolyte membrane fuel cells