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Boosting the Oxygen Reduction Performance of fe-n-c catalyst Using Zeolite as an Oxygen Reservoir

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Transactions of Tianjin University 2024年第5期30卷 428-435页

作者： Weihao Liu Qingtao Liu Xin Wan Jianglan Shui School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Space and Environment Beihang UniversityBeijing 102206China Tianmushan Laboratory Hangzhou 311115China

non-precious metal electrocatalysts(such as fe-n-c materials) for the oxygen(O_(2)) reduction reaction demand a high catalyst loading in fuel cell devices to achieve workable performance. However, the extremely low solubility of O_(2) in water creates severe mass transport resistance in the thick catalyst layer of fe-n-c catalysts. Here, we introduce silicalite-1 nanocrystals with hydrophobic cavities as sustainable O_(2) reservoirs to overcome the mass transport issue of fe-n-c catalysts. The extra O_(2) supply to the adjacent catalysts significantly alleviated the negative effects of the severe mass transport resistance. The hybrid catalyst(fe-n-c@silicalite-1) achieved a higher limiting current density than fe-n-c in the half-cell test. In the H_(2)-O_(2) and H_2-air proton exchange membrane fuel cells, fe-n-c@silicalite-1 exhibited a 16.3% and 20.2% increase in peak power density compared with fe-n-c, respectively. The O_(2)-concentrating additive provides an effective approach for improving the mass transport imposed by the low solubility of O_(2) in water.

关键词： Oxygen reduction reaction Fuel cell fe-n-c catalyst Oxygen reservoir Mass transport

fe-n-c catalysts for oxygen electroreduction under external magnetic fields:Reduction of magnetic O_(2) to nonmagnetic H_(2)O

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Journal of Energy chemistry 2022年第1期31卷 296-308,I0008页

作者： Wojciech Kicinski Jakub P.Sek Agata Kowalczyk Sylwia Turczyniak-Surdacka Anna M.nowicka Slawomir Dyjak Boguslaw Budner Mikolaj Donten Institute of chemistry Military University of Technology2 Kaliskiego Str.PL 00-908 WarsawPoland Faculty of chemistry University of WarsawPasteura 1 StrPL 02-093 WarsawPoland Faculty of chemistry Biological and Chemical Research CentreUniversity of WarsawZwirki i Wigury 101 StrPL 02-089 WarsawPoland Institute of Optoelectronics Military University of Technology.2 Kaliskiego StrPL 00-908 WarsawPoland

An extensive analysis of iron-nitrogen-carbon(fe-n-c)electrocatalysts synthesis and activity is presented concerning synthesis conditions such as initial fe content,pyrolysis temperature and atmosphere(inert n_(2),reducing nH_(3),oxidizing cl_(2) and their sequential combinations)and the influence of an external magnetic field on their performance in oxygen reduction reaction(ORR).Thermosetting porous polymers doped with fecl_(3) were utilized as the fe-n-c catalysts *** pyrolysis temperature was varied within a 700-900℃*** temperature and atmosphere of pyrolysis strongly affect the porosity and compositi on of the resultant fe-n-c catalysts,while the in itial amount of fe precursor shows much weaker *** under nH_(3) yields materials similar to those pyrolyzed under an inert atmosphere(n_(2)).In contrast,pyrolysis under cl_(2) yields carbon of peculiar character with highly disordered structure and extensive *** application of a static external magnetic field strongly enhances the ORR process(herein studied in an alkaline environment)and the enhancement correlates with the fe content in the fe-n-c *** fe-n-c materials containing ferromagnetic iron phase embedded in n-doped microporous carbon constitute attractive catalysts for magnetic field-aided anion exchange membrane fuel cell technology.

关键词： Oxygen reduction reaction fe-n-c catalyst PGM-free catalyst Magnetic field chronoamperometry Anion exchange membrane fuel cell (AEMFc)

The effect of temperature on ionic liquid modified fe-n-c catalysts for alkaline oxygen reduction reaction

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Journal of Energy chemistry 2022年第5期31卷 324-329页

作者： Thomas Wolker Kai Brunnengräber Ioanna Martinaiou nick Lorenz Gui-Rong Zhang Ulrike I.Kramm Bastian J.M.Etzold Department of chemistry Ernst-Berl-Institut für Technische und Makromolekulare ChemieTechnical University of Darmstadt64287 DarmstadtGermany Department of chemistry Catalysts and Electrocatalysts GroupTechnical University of Darmstadt64287 DarmstadtGermany Graduate School of Excellence Energy Science and Engineering Technical University of Darmstadt64287 DarmstadtGermany Department of Materials and Earth Sciences Technical University of Darmstadt64287 DarmstadtGermany School of chemical Engineering and Technology Tiangong UniversityTianjin 300387China

Modifying solid catalysts with an ionic liquid layer is an effective approach for boosting the performance of both Pt-based and non-precious metal catalysts toward the oxygen reduction reaction. While most studies operated at room temperature it remains unclear whether the IL-associated boosting effect can be maintained at elevated temperature, which is of high relevance for practical applications in low temperature fuel cells. Herein, fe-n-c catalysts were modified by introducing small amounts of hydrophobic ionic liquid, resulting in boosted electrocatalytic activity towards the alkaline oxygen reduction reaction at room temperature. It is demonstrated that the boosting effect can be maintained and even strengthened when increasing the electrolyte temperature up to 70℃. These findings show for the first time that the incorporation of ionic liquid is a suited method to obtain advanced noble metal-free electrocatalysts that can be applied at operating temperature condition.

关键词： Oxygen reduction reaction non-precious metal catalyst Ionic liquid fe-n-c catalyst Temperature effect

High-performance fe-n-c electrocatalysts with a "chain mail" protective shield

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nano Materials Science 2021年第4期3卷 420-428页

作者： Zixun Yu chang Liu Junsheng chen Ziwen Yuan Yuan chen Li Wei School of chemical and Biomolecular Engineering The University of SydneyDarlingtonNSW2006Australia

nitrogen-coordinated iron atoms on carbon supports(fe-n-c)are among the most promising noble-metal-free electrocatalysts for oxygen reduction reaction(ORR).However,their unsatisfactory stability limits their prac-tical ***,we demonstrate a dual-shell fe-n-c electrocatalyst with excellent catalytic activity and long-term *** and dopamine are sequentially polymerized on a fumed silica nanoparticle *** precursor(fecl_(3))and pore formation agent(Zncl_(2))were loaded on the inner polypyrrole *** carbonization,the Zn evaporation creates abundant mesopores in the polydopamine-derived outer carbon shell,forming a "chain mail"like outer shell that protects fe-n-c active sites loaded on the inner carbon shell and enables efficient mass *** tuning of the shield thickness and porosity affords the optimal electrocatalyst with a large surface area of 934 m^(2)g^(-1) and a high fe loading of 2.04 wt%.This electrocatalyst delivers excellent ORR activity and superior stability in both acidic and alkaline *** Zn-air batteries fabricated from this electrocatalyst delivers a high-power density of 257 mW cm^(-2) and impressive durability of continuous discharging over 250 *** a graphitic and porous carbon protective shell can be further extended to other electrocatalysts to enable their practical applications in energy conversion and storage.

关键词： fe-n-c catalyst Oxygen reduction reaction Stability Zinc-air battery

Size-dependent activity of fe-n-doped mesoporous carbon nanoparticles towards oxygen reduction reaction

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Green carbon 2024年第2期2卷 221-230页

作者： Yilun Zhao Zhengbin Tian Wenquan Wang Xiaohui Deng Jo-chi Tseng Guanghui Wang Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of SciencesQingdao 266101China Shandong Energy Institute Qingdao 266101China Qingdao new Energy Shandong Laboratory Qingdao 266101China University of chinese Academy of Sciences Beijing 100049China Japan Synchrotron Radiation Research Institute Hyogo 679-5198Japan

The rational design of fe–n–c catalysts that possess easily accessible active sites and favorable mass transfer,which are usually determined by the structure of catalyst supports,is crucial for the oxygen reduction reaction(ORR).In this study,an oleic acid-assisted soft-templating approach is developed to synthesize size-controlled nitrogen-doped carbon nanoparticles(ranging from 130 nm to 60 nm and 35 nm,respectively)that feature spiral mesopores on their surface(SMcs).next,atomically dispersed fe–nx sites are fabricated on the size-tunable SMcs(fe1/SMc-x,where x represents the SMc size)and the size-dependent activity toward ORR is *** is found that the catalytic performance of fe1/SMcs is significantly influenced by the size of SMcs,where the fe1/SMc-60 catalyst shows the highest ORR activity with a half-wave potential of 0.90 V *** in KOH electrolyte,indicating that the gas-liquid-solid three-phase interface on the fe1/SMc-60 enhances the accessibility of fe–nx *** addition,when using fe1/SMc-60 as the cathode catalyst in aqueous zinc-air batteries(ZABs),it delivers a higher open-circuit voltage(1.514 V),a greater power density(223 mW cm^(−2)),and a larger specific capacity/energy than Pt/c-based *** results further highlight the potential of fe1/SMc60 for practical energy devices associated with ORR and the importance of size-controlled synthesis of SMcs.

关键词： Soft-templating approach Size-dependent activity fe-n-c catalyst Oxygen reduction reaction Zinc-air battery