High Durability of Fe-N-C Single-Atom Catalysts with Carbon Vacancies toward the Oxygen Reduction Reaction in Alkaline Media.
basic_science · Level V
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- Record sourced from PubMed, PMID 36630970.
- Also identified by DOI 10.1002/adma.202210714.
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Abstract
Single-atom catalysts (SACs) have attracted extensive interest to catalyze the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. However, the development of SACs with high selectivity and long-term stability is a great challenge. In this work, carbon vacancy modified Fe-N-C SACs (Fe<sub>H</sub> -N-C) are practically designed and synthesized through microenvironment modulation, achieving high-efficient utilization of active sites and optimization of electronic structures. The Fe<sub>H</sub> -N-C catalyst exhibits a half-wave potential (E<sub>1/2</sub> ) of 0.91 V and sufficient durability of 100 000 voltage cycles with 29 mV E<sub>1/2</sub> loss. Density functional theory (DFT) calculations confirm that the vacancies around metal-N<sub>4</sub> sites can reduce the adsorption free energy of OH*, and hinder the dissolution of metal center, significantly enhancing the ORR kinetics and stability. Accordingly, Fe<sub>H</sub> -N-C SACs presented a high-power density and long-term stability over 1200 h in rechargeable zinc-air batteries (ZABs). This work will not only guide for developing highly active and stable SACs through rational modulation of metal-N<sub>4</sub> sites, but also provide an insight into the optimization of the electronic structure to boost electrocatalytical performances.