Nitrogen and atomic Fe dual-doped porous carbon nanocubes as superior electrocatalysts for acidic H2-O2 PEMFC and alkaline Zn-air battery

Air cathodes with high electrocatalytic activity are vital for developing H-2/O-2 proton exchange membrane fuel cells (PEMFC) and Zn-air batteries. However, the state-of-the-art air cathodes suffer from either limited catalytic activity or high cost, which thus hinder their applications. Herein, we designed ZIF-8 derived nitrogen and atomic iron dual-doped porous carbon nanocubes as high-quality catalysts for ORR, through a novel gas-doping approach. The porous carbon nanocubic architecture and abundant Fe-Nx active species endow ZIF-8 derived single atomic iron catalyst (PCN-A@Fe SA) with superior catalytic activity, and surpass Pt/C and a majority of the reported catalysts. Both XAS and DFT calculations suggest that Fe2+N4 moieties are the main active centers that are favorable for oxygen affinity and OH* intermediate desorption, which can result in promising catalytic performance. Most importantly, PCN-A@Fe SA can achieve power density of 514 mW cm(-2) as cathodic catalyst in a PEMFC and discharge peak power density of 185 mW cm(-2) in an alkaline Zn-air battery. The outstanding performance is derived from both the high specific surface area and high-density of iron single atom in nitrogen doped nanocubic carbon matrix. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

By utilizing a novel gas-doping approach, nitrogen and atomic iron dual-doped porous carbon nanocubes derived from ZIF-8 were designed as high-quality catalysts for ORR.