Pérez-Rodríguez S, Torres D, Izquierdo MT, Zitolo A, Bibent N, Sougrati M, Jaouen F, Celzard A, Fierro V. Hierarchical Porous Fe
3C@Fe-N-C Catalysts from Tannin-Fe(III) Complexes for Efficient Oxygen Reduction.
SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2025;
21:e2406887. [PMID:
39711268 DOI:
10.1002/smll.202406887]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 12/12/2024] [Indexed: 12/24/2024]
Abstract
The rational design of metal-nitrogen-doped carbons (M-N-C) from available and cost-effective sources featuring high electrocatalytic performance and stability is attractive for the development of viable low-temperature fuel cells. Herein, mimosa tannin, an abundant polyphenol easily extracted from the Mimosa plant, is used as a natural carbon source to produce a tannin-Fe(III) coordination complex. This process is assisted by Pluronic F127, which acts as both a surfactant and a promoter of Fe-Nx active sites. After carbonization in the presence of urea as a nitrogen precursor, this organic tannin-Fe(III) framework produces Fe3C nanoparticles encapsulated on a Fe-N-C single-atom catalyst with hierarchical porosity. The optimal catalyst, with a Pluronic F127/mimosa tannin mass ratio of 0.5, exhibits high ORR performance in both alkaline and acidic electrolytes, with half-wave potentials of 0.87 and 0.74 V versus RHE, respectively. In addition, good performance is achieved in practical hydrogen polymer-electrolyte membrane fuel cells using OH-- or H+-conducting membranes with peak power densities of 242 and 200 mW cm-2 at cell voltages of 0.43 and 0.3 V, respectively. The synthetic approach can be explored to design new renewable M-N-C electrodes for electrochemical energy conversion or storage devices due to tannin's exceptional ability to coordinate metals.
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