Establishing structure/property relationships in atomically dispersed Co-Fe dual site M-Nx catalysts on microporous carbon for the oxygen reduction reaction

作者：Wang, Kai; Liu, Jiapeng; Tang, Zhenghua^*; Li, Ligui; Wang, Zheng; Zubair, Muhammad; Ciucci, Francesco^*; Thomsen, Lars; Wright, Joshua; Bedford, Nicholas M.^*

来源：Journal of Materials Chemistry A, 2021, 9(22): 13044-13055.

DOI：10.1039/d1ta02925h

• SINGLE-ATOM CATALYSTS
• CATHODE CATALYSTS
• ACTIVE-SITES
• FUEL-CELLS
• METAL-FREE
• IRON
• ELECTROCATALYSTS
• IDENTIFICATION
• NANOSPHERES
• COMPLEXES

Coupled metal-nitrogen-carbon (M-N-x-C) materials show great promise as platinum-group-metal (PGM) free catalysts for the oxygen reduction reaction (ORR). Herein, we report a facile strategy to construct atomically dispersed Co-Fe dual sites enriched on the surface of nitrogen doped microporous carbon (NC) as an efficient electrocatalyst for ORR. Synchrotron X-ray techniques indicate that the Co and Fe atoms are strongly correlated while further revealing that the longer-range lattice structure of NC is highly tunable. Density functional theory calculations reveal that the Co-Fe dimers are incorporated in the slightly disordered NC substrate, providing a lower adsorption free energy for O-2. The as-prepared CoFe-NC catalyst exhibited excellent ORR activities, while a CoFe-NC based zinc-air battery exhibited a power density of 115 mW cm(-2) and a specific capacity of 791 mA h g(-1). This work showcases a straightforward methodology for creating atomically dispersed catalysts and illustrates the importance of understanding how dual metal sites impact electrocatalytic activity.