Key Takeaways & Executive Findings
- •• FeOx-N/C catalyst, derived from Ketjenblack carbon, PIL, and Fe(NO3)3, exhibits high ORR activity in both alkaline and acidic media. • The PIL [Hvim]NO3 ensures uniform dispersion of Fe3+ and generates porosity via NO3− decomposition, enhancing catalytic performance. • Zinc-air battery assembled with FeOx-N/C achieves a peak power density of 185 mW·cm−2, demonstrating practical applicability. • The catalyst's wide pH range, high activity, and simple preparation make it a promising non-precious metal alternative to Pt-based catalysts.
Abstract
To replace precious metal oxygen reduction reaction (ORR) electrocatalysts, many transition metals and N-doped carbon composites have been proposed in the last decade resulting in their rapid development as promising non-precious metal catalysts. We used Ketjenblack carbon as the precursor and mixed it with a polymeric ionic liquid (PIL) of [Hvim]NO3 and Fe(NO3)3, which was thermally calcined at 900 °C to produce a porous FeOx, N co-doped carbon material denoted FeOx-N/C. Because the PIL of [Hvim]NO3 strongly combines with and disperses Fe3+ ions, and NO3− is thermally pyrolyzed to form the porous structure, the FeOx-N/C catalyst has a high electrocatalytic activity for the ORR in both 0.1 mol L−1 KOH and 0.5 mol L−1 H2SO4 electrolytes. It was used as the catalyst to assemble a zinc-air battery, which had a peak power density of 185 mW·cm−2. Its superior electrocatalytic activity, wide pH range, and easy preparation make FeOx-N/C a promising electrocatalyst for fuel cells and metal-air batteries.
1. Introduction
Because of the high theoretical energy density, the fuel cell and metal-air battery (MAB) are considered as promising new power sources to cope with the global energy crisis[1]. In the fuel cell and MAB, the oxygen reduction reaction (ORR) is a crucial electrochemical reaction. However, the ORR is sluggish in kinetics and needs electrocatalysts[2]. Despite the high catalytic efficiency, Pt-based catalysts have largely prohibited the large-scale applications due to their high price and poor durability[3]. Therefore, a lot of work has been conducted to develop the non-precious metal catalysts (NPMCs) to replace the existing Pt-based catalysts.
Among alternative NPMCs, the transition metal loaded on nitrogen-doped carbon (TM-N/C) materials attract intensive interest and hold the great promise to work in the place of the Pt-based electrocatalysts[4–6]. As an ideal carbon precursor, Ketjenblack carbon (KB) features good electronic conductivities, large specific surface area, and good commercial availability, which is widely investigated as the ORR catalyst by modifying with metal and/or heteroatoms[4,7]. For instance, urea was used as N source to prepare the N-doped KB, which was further used to fabricate a Fe, Ag-N-KB electrocatalyst for ORR[8]. The Cu-N-KB[9] and the Fe(or Co)-N-KB[10] were separately obtained by introducing N, N-dimethylformamide and ethylene diamine tetraacetic acid into the structure of KB, both of which were determined to efficiently catalyze the ORR.
In recent years, polymeric ionic liquids (PILs) are rapidly developed as good precursors for NPMCs[11,12]. On the one hand, heteroatoms in PILs can spontaneously serve as the heteroatom resources. On the other hand, the negligible volatility enables the high doping efficiency. Therefore, various PILs are widely investigated to synthesize the heteroatom-doped carbon materials with high ORR activity[13–15]. These unique properties inspire us to utilize the PIL to modify KB to prepare the TM-N/C catalyst for ORR.
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GAO Jian, WANG Xin-yao, MENG Ling-xin, YIN Zhen, MA Na, TAN Xiao-yao, ZHANG Peng (2025). A carbon material doped with both porous FeOx and N as an efficient catalyst for oxygen reduction reactions. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2024-39-06-11)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
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Frequently Asked Questions
What is the FeOx-N/C catalyst?
FeOx-N/C is a porous carbon material co-doped with iron oxide (FeOx) and nitrogen, synthesized by thermal calcination of Ketjenblack carbon with a polymeric ionic liquid [Hvim]NO3 and Fe(NO3)3 at 900°C. It serves as an efficient non-precious metal electrocatalyst for the oxygen reduction reaction (ORR).
How does the FeOx-N/C catalyst perform in different electrolytes?
The FeOx-N/C catalyst exhibits high electrocatalytic activity for the ORR in both alkaline (0.1 mol L−1 KOH) and acidic (0.5 mol L−1 H2SO4) electrolytes, demonstrating a wide pH range applicability.
What is the peak power density of the zinc-air battery using FeOx-N/C?
The zinc-air battery assembled with FeOx-N/C as the catalyst achieves a peak power density of 185 mW·cm−2, indicating its practical potential in metal-air batteries.
Why is the polymeric ionic liquid [Hvim]NO3 important in the synthesis?
The PIL [Hvim]NO3 strongly combines with and disperses Fe3+ ions, ensuring uniform distribution of iron species. Additionally, the NO3− anions decompose at high temperature, generating abundant pores in the carbon structure, which enhances the catalytic performance.
What are the advantages of FeOx-N/C over Pt-based catalysts?
FeOx-N/C offers a lower cost, easier preparation, and comparable electrocatalytic activity for ORR, along with good durability and wide pH range, making it a promising alternative to expensive Pt-based catalysts.
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