聚丙烯腈
材料科学
氧化钴
钴
催化作用
氧化物
石墨
氧化石墨
化学工程
氧化铁
复合材料
冶金
化学
聚合物
有机化学
工程类
作者
Rushi U. Soni,Vaibhav A. Edlabadkar,Parwani M. Rewatkar,Abm Shaheen ud Doulah,Nicholas Leventis,Chariklia Sotiriou‐Leventis
出处
期刊:Carbon
[Elsevier]
日期:2022-06-01
卷期号:193: 107-127
被引量:7
标识
DOI:10.1016/j.carbon.2022.02.080
摘要
We demonstrate the Fe- or Co-catalyzed preparation of graphitic carbon aerogels that bypasses the typical use of supercritical fluid drying, and takes place at much lower temperatures (800–1500 °C) than conventional graphitization (2500–3300 °C). The process starts with preparation of polyacrylonitrile (PAN)-crosslinked iron and cobalt oxide xerogel powders via surface-initiated free-radical polymerization of acrylonitrile on the porous solid networks of sol-gel-derived particle suspensions of the oxides. The resulting wet-gel oxide/polymer composite powders were dried under vacuum at 50 °C to xerogel powders, which were compressed into desirable form factors, e.g., discs or cylinders. These compacts were then aromatized (300 °C, O2), and subsequently carbonized in the range of 800 °C to 1500 °C under Ar. In situ carbothermal reduction of the oxide networks by the newly produced carbon yielded catalytic-toward-graphitization Fe(0) or Co(0) nanoparticles embedded within the carbons. Post-pyrolysis, those metallic nanoparticles were removed with aqua regia leaving behind pure graphitic carbon aerogels. Chemical characterization of materials up to aromatization was carried out with solid-state 13C NMR; characterization of the terminal graphite aerogels was based on powder-XRD, Raman, TEM, SEM, XPS and N2-sorption. Porosities in the range of 63%–78% v/v were created during aromatization, and mainly during pyrolytic carbonization. The best quality graphite aerogels were obtained with iron at 1500 °C. These materials consisted of 99.8% w/w graphitic carbon, the crystallite domain size along the (002) plane reached 170 Å, and the crystallite width along the a-axis was 70 nm.
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