化学
催化作用
质子交换膜燃料电池
硫黄
极性效应
阴极
吸附
组合化学
氧还原反应
纳米技术
电化学
化学工程
碳纤维
物理化学
有机化学
电极
材料科学
工程类
复合材料
复合数
作者
Yeongdong Mun,Seong Gyu Lee,Kyeounghak Kim,Seongbeen Kim,Seung–Hyun Lee,Jeong Woo Han,Jin Woo Lee
摘要
Replacement of Pt-based oxygen reduction reaction (ORR) catalysts with non-precious metal catalysts (NPMCs) such as Fe/N/C is one of the most important issues in the commercialization of proton exchange membrane fuel cells (PEMFCs). Despite numerous studies on Fe/N/C catalysts, a fundamental study on the development of a versatile strategy is still required for tuning the kinetic activity of a single Fe-N4 site. Herein, we report a new and intuitive design strategy for tuning and enhancing the kinetic activity of a single Fe-N4 site by controlling electron-withdrawing/donating properties of a carbon plane with the incorporation of sulfur functionalities. The effect of electron-withdrawing/donating functionalities was elucidated by experimentation and theoretical calculations. Finally, the introduction of an oxidized sulfur functionality decreases the d-band center of iron by withdrawing electrons, thereby facilitating ORR at the Fe-N4 site by lowering the intermediate adsorption energy. Furthermore, this strategy can enhance ORR activity without a decrease in the stability of the catalyst. This simple and straightforward approach can be a cornerstone to develop optimum NPMCs for application in the cathodes of PEMFCs.
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