Guilong Lu, Zewen Shen, Philipp Schwiderowski, Jannik Böttger, Tim Herrendorf, Wolfgang Kleist, Xiaoyu Li, Guixia Zhao, Baoxiang Peng, Xiubing Huang, Martin Muhler
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引用次数: 0
Abstract
Both direct pyrolysis and post-impregnation are employed for the synthesis of a 3D macroporous carbon-supported Fe/N−C catalyst in this study. By comparing the microstructure, physicochemical properties, and local electronic structure of the products obtained from both preparation methods, the underlying formation mechanisms of atomic Fe sites are proposed based on the degree of carbonization of carbon-based precursors. As embedded Fe ions significantly facilitate the carbonization of carbon-based precursors to form highly stable carbon supports with a certain degree of graphitization, Fe−Nx active sites are the predominant active sites in the catalysts prepared by the direct pyrolysis method, as expected. In contrast, the absence of metal salts in the precursor results in an inadequate carbonization process, leading to pyrolyzed products with limited resistance to concentrated NaOH. This deficiency accounts for the presence of a significant number of oxygen defects in the bare carbon supports. Since metal impregnation and subsequent reduction treatment possess a limited capacity to recover these O-defects, the catalysts obtained via the post-impregnation method exhibit distinct Fe−OyNx configurations. The solvent-free oxidative coupling of benzylamine was used as a probe reaction to evaluate the catalytic activity of these atomic Fe sites. The catalytic results demonstrate the superior catalytic activity and recyclability of Fe−Nx active sites compared with Fe−OyNx moieties, thereby confirming the superiority of the direct pyrolysis approach over the post-impregnation method.
期刊介绍:
The Journal of Materials Chemistry A, B & C covers a wide range of high-quality studies in the field of materials chemistry, with each section focusing on specific applications of the materials studied. Journal of Materials Chemistry A emphasizes applications in energy and sustainability, including topics such as artificial photosynthesis, batteries, and fuel cells. Journal of Materials Chemistry B focuses on applications in biology and medicine, while Journal of Materials Chemistry C covers applications in optical, magnetic, and electronic devices. Example topic areas within the scope of Journal of Materials Chemistry A include catalysis, green/sustainable materials, sensors, and water treatment, among others.