posted on 2021-05-10, 15:38authored bySyed Shoaib
Ahmad Shah, Tayyaba Najam, Muhammad Sufyan Javed, Mohammed M. Rahman, Panagiotis Tsiakaras
Fe–N–C-based
electrocatalysts have been developed
as an encouraging substitute compared to their expensive Pt-containing
equivalents for the oxygen reduction reaction (ORR). However, they
still face major durability challenges from the in- situ production
of Fenton radicals. Therefore, the synthesis of Fe-free ORR catalysts
is among the emerging concerns. Herein, we have precisely applied
a multistep heating strategy to produce mesoporous N-doped carbon
nanostructures with Mn-/Co-Nx dual moieties
from mixed-metal zeolitic imidazolate frameworks (ZIFs). It is found
that their unique structure, with dual-metallic active sites, not
only offers a high electrochemical performance for the ORR (E1/2 = 0.83 V vs reversible
hydrogen electrode (RHE) in acid media), but also enhances the operational
durability of the catalyst after 20 000 cycles with 97% of
retention and very low H2O2 production (<5%)
in 0.1 M HClO4. In addition, the catalyst performs well
toward the ORR also in alkaline solution (exhibiting E1/2 = 0.90 V and 30 000 cyclic stability).