Highly active sites of low spin FeⅡN4 species: The identification and the ORR performance
single sites of FeN4, oxygen reduction reaction, structure-performance correlation, electrocatalysis
Over recent years, catalytic materials of Fe-N-C species have been recognized being active for oxygen reduction reaction (ORR). However, the identification of active site remains challenging as it generally involves a pyrolysis process and mixed components being obtained. Herein Fe3C/C and Fe2N/C samples were synthesized by temperature programmed reduction of Fe precursors in 15% CH4/H2 and pure NH3, respectively. By acid leaching of Fe2N/C sample, only single sites of FeN4 species were presented, providing an ideal model for identification of catalytic functions of the single sites of FeN4 in ORR. A correlation was conducted between the concentration of FeⅡN4 in low spin state by Mössbauer spectra and the kinetic current density at 0.8 V in alkaline media, and such a structure-performance correlation assures the catalytic roles of low spin FeⅡN4 species as highly active sites for the ORR.
Tsinghua University Press
Huizhu Cai, Bingbing Chen, Xiao Zhang, Yuchen Deng, Dequan Xiao, Ding Ma, Chuan Shi. Highly active sites of low spin FeⅡN4 species: The identification and the ORR performance. Nano Research 2021, 14(1): 122-130.