Xing Li,Lei Xing,Chunyu Zhang,Shudan He,Fanghua Liu,Zhen Chen,Huazhen Chang,Junhua Li
Catalytic solvent regeneration is widely considered a promising solution for addressing the intensive heat duty of amine-based carbon dioxide (CO 2 ) capture. This highly challenging application has motivated researchers to develop excellent catalysts with high activity and durability. In this study, we engineered active and durable Fe − N − C catalyst coated with high-graphitization carbon layers (labeled Phen − Fe − N − C) through a secondary thermal pyrolysis treatment. The multiple graphite layers and atomic metal sties were verified by experimental characterization and coordination structure analysis. The improved graphite layers further enhanced the activity of Fe − N − C sites, providing more acid sites for proton-electron transfer and C − N breaking during solvent regeneration (or CO 2 desorption). Thus, the maximal CO 2 desorption rate increased by 50 % when Fe − N − C was used compared with that of the blank case, and the rate further increased by 27 % when Phen − Fe − N − C was used. After 15 days of hydrothermal testing, the single Fe atom over the spent catalysts presented no significant aggregation or dissolution in the solvent, validating the durability of Phen − Fe − N − C. This work demonstrates a feasible and novel strategy to improve M − N − C materials for efficient and robust CO 2 desorption from amine solvents toward energy-saving CO 2 capture.
Refreshing the record of the electrocatalytic activity for bifunctional oxygen electrocatalysis is the first priority of developing next-generation rechargeable zinc-air batteries. A Δ E indicator to evaluate the bifunctional electrocatalytic activity has stagnated with a record of Δ E > 0.60 V for decades. Herein, a bifunctional oxygen electrocatalyst is developed to afford an ultrahigh bifunctional electrocatalytic activity of Δ E = 0.57 V and realize high-performance rechargeable zinc-air batteries. Specifically, atomically dispersed Fe-N-C sites and NiFeCe layered double hydroxides are integrated to afford a composite FeNC@LDH electrocatalyst, following the guidance of the data-driven analysis. The FeNC@LDH electrocatalyst demonstrates a record-breaking electrocatalytic activity of Δ E = 0.57 V, far exceeding the state-of-the-art level by ca. 60 mV. Practical ampere-hour-scale zinc-air batteries are constructed with a capacity of 6.4 Ah and cycle under 1.0 A and 1.0 Ah conditions. This work affords a record-breaking bifunctional electrocatalyst for ampere-hour-scale zinc-air batteries in future application scenarios.
Yifan Zhang,Sylvestre Ndayiragije,Ming Chen,Xiaobo Wang,Lihua Zhu,Nan Wang
Fe- and nitrogen-doped carbonaceous (Fe-N-C) sites supported on MnO 2 (Fe-N-C@MnO 2 ) were prepared by a solvent-free mechanochemical method for peroxymonosulfate (PMS) activation to degrade norfloxacin (NFX). After a 50-min ball milling of iron(II) phthalocyanine (Fe( II )Pc) and MnO 2 at a weight ratio of 7.5 %, the obtained Fe-N-C@MnO 2 exhibited exceptional activity in PMS activation, achieving nearly complete degradation of NFX in 5 min with a rate constant of 0.62 min −1 . This rate constant was 11.5 and 28.2 times higher than that for milled MnO 2 (bm-MnO 2 ) and the mixture of Fe( II )Pc and MnO 2 , respectively. Alternative iron sources (FeSO 4 , FeCl 2 , Fe(III)-EDTA) and phthalocyanine showed no enhancement. Characterization revealed Fe-N-C@MnO 2 possessed abundant Mn 3+ , oxygen vacancies and Fe-N-C sites. Combined experimental and computational studies demonstrated Fe-N-C@MnO 2 simultaneously enhanced the 1 O 2 generation and facilitated the formation of SO 4 •− , •OH and O 2 •− , with contributions to NFX degradation following: 1 O 2 > •OH ≈ O 2 •− > SO 4 •− . This work establishes mechanochemical coordination engineering as a facile strategy for constructing high-performance metal-N-C hybrid catalysts.
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