Fe-N-C catalysts decorated with oxygen vacancies-rich CeOx to increase oxygen reduction performance for Zn-air batteries

Platinum group metal (PGM)-free catalysts represented by nitrogen and iron co-doped carbon (Fe-N-C) catalysts are desirable and critical for metal-air batteries, but challenges still exist in performance and stability. Here, cerium oxides (CeOx) are incorporated into a two-dimensional Fe-N-C catalyst (FeNC-Ce-950) via a host-guest strategy. The Ce4+/Ce3+ redox system creates a large number of oxygen vacancies for rapid O2 adsorption to accelerate the kinetics of oxygen reduction reaction (ORR). Consequently, the assynthesized FeNC-Ce-950 catalyst exhibits a half-wave potential (E1/2) of 0.921 V and negligible decay (<2 mV for DE1/2) after 5,000 accelerated durability cycles, significantly outperforming most of ORR catalysts reported in recent years and precious metal counterparts. When applied in a zinc-air battery, it demonstrates a peak power density of 175 mW cm(-2) and a specific capacity of 757 mAh gZn(-1). This study also provides a reference for the exploration of Fe-N-C catalysts decorated with variable valence metal oxides. (c) 2023 Elsevier Inc. All rights reserved.

Automated summary

A two-dimensional Fe-N-C catalyst decorated with cerium oxides (CeOx) is developed by a host-guest strategy, which provides a large number of oxygen vacancies for accelerated oxygen reduction kinetics. The synthesized catalyst shows superior performance and stability, outperforming most reported ORR catalysts and precious metals. It demonstrates high peak power density and specific capacity in a zinc-air battery.