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 (CeO) are incorporated into a two-dimensional Fe-N-C catalyst (FeNC-Ce-950) via a host-guest strategy. The Ce/Ce redox system creates a large number of oxygen vacancies for rapid O adsorption to accelerate the kinetics of oxygen reduction reaction (ORR). Consequently, the as-synthesized FeNC-Ce-950 catalyst exhibits a half-wave potential (E) of 0.921 V and negligible decay (<2 mV for ΔE) 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 and a specific capacity of 757 mAh g. This study also provides a reference for the exploration of Fe-N-C catalysts decorated with variable valence metal oxides.
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http://dx.doi.org/10.1016/j.jcis.2023.01.057 | DOI Listing |
Chem Sci
January 2025
Interdisciplinary Research Center for Sustainable Energy Science and Engineering (IRC4SE2), School of Chemical Engineering, Zhengzhou University Henan 450001 China
The exceptional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances of core-shell catalysts are well documented, yet their activity and durability origins have been interpreted only based on the static structures. Herein we employ a NiFe alloy coated with a nitrogen-doped graphene-based carbon shell (NiFe@NC) as a model system to elucidate the active structure and stability mechanism for the ORR and OER by combining constant potential computations, molecular dynamic simulations, and experiments. The results reveal that the synergistic effects between the alloy core and carbon shell facilitate the formation of Fe-N-C active sites and replenish metal sites when central metal atoms detach.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Aviation Oil and Material, Air Force Logistics Academy, 72 Xi Ge Road, Xuzhou, Jiangsu 221000, China.
Metal-air batteries desire highly active, durable, and low-cost oxygen reduction catalysts to replace expensive platinum (Pt). The Fe-N-C catalyst is recognized as the most promising candidate for Pt; however, its durability is hindered by carbon corrosion, while activity is restricted due to limited oxygen for the reaction. Herein, TiN is creatively designed to be hybridized with Fe-N-C (TiN/Fe-N-C) to relieve carbon corrosion and absorb more oxygen when catalyzing oxygen reduction.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Key Laboratory for Special Functional Aggregate Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China.
The adsorption of DNA probes onto nanomaterials represents a promising bioassay technique, generally employing fluorescence or catalytic activity to generate signals. A significant challenge is maintaining the catalytic activity of chromogenic catalysts during detection while enhancing accuracy by overcoming the limitations of single-signal transmission. This article presents an innovative multimodal analysis approach that synergistically combines the oxidase-like activity of Fe-N-C nanozyme (Fe-NC) with red fluorescent carbon quantum dots (R-CQDs), further advancing the dual-mode analysis method utilizing R-CQDs@Fe-NC.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Tianjin University, School of Materials science and engineering, School of Materials Science and Engineering, Tianjin University, 300072, Tianjin, CHINA.
Fe-N-C catalyst is the most promising alternative to platinum catalyst for proton-exchange membrane fuel cells (PEMFCs), however its high performance cannot be maintained for a long enough time in device. The construction of a new Fe coordination environment that is different from the square-planar Fe-N 4 configuration in Fe-N-C catalyst is expected to break current stability limits, which however remains unexplored. Here, we report the conversion of Fe-N-C to a new FeNxSey catalyst, where the Fe sites are three-dimensionally (3D) co-coordinated by N and Se atoms.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Xiamen University, College of Chemistry and Chemical Engineering, Siming streat, Xiamen, CHINA.
Learning from nature has garnered significant attention in the scientific community for its potential to inspire creative solutions in material or catalyst design. The study reports a biomimetic single selenium (Se) site-modified carbon (C) moiety that retains the unique reactivity of selenoenzyme with peroxides, aiming to selectively catalyze the oxygen reduction reaction (ORR). The as-designed Se-C demonstrates nearly 100% 4-electron selectivity, evidenced by 0.
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