Title: Revealing the Optimal Configuration for Synergy Effect of Metal Nanoparticles and MN4 Sites for Oxygen Reduction Reaction

Authors: Xiaoyang Cheng, Yanrong Li, Jinhong Zheng, Shuhu Yin, Chongtai Wang, Ximing Qu, Jian Yang,Yanxia Jiang*, Shigang Sun*

Abstract: Metal-nanoparticles (M-NPs) can adjust the electronic structure of the singly atomic MN₄ to promote ORR reactivity effectively. However, the synergy effect of M-NPs and MN₄ is influenced in a multifactorial way, and is difficult to investigate their separate effects on promoting ORR. Herein, we establish a new strategy to synthesize catalysts containing highly active MN₄ and M-NPs composite site and study their separate effects on ORR specifically. The MN₄ can be controlled in high-density, and meanwhile the M-NPs can be regulated precisely at very fine nanoscale. Our studies reveal that the MN₄ density shall be high enough so that the ORR reactivity can depend on the M-NPs size. The catalyst with clusters, i.e. H-(M_Cs-(FeCo)N₄), can show the optimal ORR activity (j_m@0.85 V) ~1.5 times as high as commercial Pt/C. This work not only develop a high-performance ORR catalyst, but also propose a reliable strategy for the MN₄/M-NPs composite site catalyst synthesis.

Full-Link: https://www.sciencedirect.com/science/article/pii/S2211285522005183