Scalable fabrication and active site identification of MOF shell-derived nitrogen-doped carbon hollow frameworks for oxygen reduction  

作　　者：Jiashen Meng Ziang Liu Xiong Liu Wei Yang Lianzhou Wang Yan Li Yuan-Cheng Cao Xingcai Zhang Liqiang Mai 

机构地区：[1]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan,430070,China [2]Nanomaterials Centre,School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology,The University of Queensland,St Lucia,QLD,4072,Australia [3]Shenzhen Power Supply Col.Ltd.,Shenzhen City,China [4]State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan,430074,China [5]John A.Paulson School of Engineering and Applied Sciences,Harvard University,Cambridge,MA,02138,United States

出　　处：《Journal of Materials Science & Technology》2021年第7期186-192,共7页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China (51832004 and 51521001);the National Key Research and Development Program of China (2016YFA0202603);the Natural Science Foundation of Hubei Province (2019CFA001);the Programme of Introducing Talents of Discipline to Universities (B17034);the Yellow Crane Talent (Science & Technology) Program of Wuhan City。

摘　　要：Nitrogen-doped carbon materials as promising oxygen reduction reaction(ORR) electrocatalysts attract great interest in fuel cells and metal-air batteries because of their relatively high activity, high surface area, high conductivity and low cost. To maximize their catalytic efficiency, rational design of efficient electrocatalysts with rich exposed active sites is highly desired. Besides, due to the complexity of nitrogen species, the identification of active nitrogen sites for ORR remains challenging. Herein, we develop a facile and scalable template method to construct high-concentration nitrogen-doped carbon hollow frameworks(NC), and reveal the effect of different nitrogen species on theirORRactivity on basis of experimental analysis and theoretical calculations. The formation mechanism is clearly revealed, including low-pressure vapor superassembly of thin zeolitic imidazolate framework(ZIF-8) shell on ZnO templates,in situ carbonization and template removal. The obtained NC-800 displays better ORR activity compared with other NC-700 and NC-900 samples. Our results indicate that the superior ORR activity of NC-800 is mainly attributed to its content balance of three nitrogen species. The graphitic N and pyrrolic N sites are responsible for lowering the working function, while the pyridinic N and pyrrolic N sites as possible active sites are beneficial for increasing the density of states.

关 键 词：MOF shell Nitrogen-doped carbon Hollow framework Oxygen reduction Active nitrogen sites 

分 类 号：TM911.4[电气工程—电力电子与电力传动] O643.36[理学—物理化学]