Iron oxide-based catalyst of (Fe1-xMgx)O·Fe2O3 with well-dispersed active sites favoring carbon nanotubes growth for high-performance microwave absorption

• Published in: Journal of alloys and compounds Vol. 990; p. 174286
• Main Authors: Sun, Jianning, Sun, Qihui, Wang, Junwei, Jian, Xian, Guo, Xingmin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.06.2024
• Subjects: Chemical vapor deposition; Iron-based oxides; Microwave absorption; Three-dimensional network carbon nanotube; Iron-based oxides; Microwave absorption; Three-dimensional network carbon nanotube; Chemical vapor deposition
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2024.174286

Traditional catalysts for carbon nanotubes growth require specific substrates to prevent catalyst aggregation, then designing environmentally friendly and efficient catalysts remains enormous challenges. Herein, we developed an iron oxide-based catalyst of (Fe1-xMgx)O·Fe2O3 with catalytic active sites for the low-cost growing of carbon nanotubes (CNT) in chemical vapor deposition (CVD) system. This (Fe1-xMgx)O·Fe2O3 was prepared by solid-phase sintering of iron oxide and magnesium oxide uniformly mixed in mass ratio of 3%∼20 wt% MgO at 1400 °C. The introduction of magnesium oxide possesses some advantages of reducing the decomposition temperature of iron oxide and hindering the aggregation of as-formed Fe catalyst during CVD process. Furthermore, the in-situ growing CNT wrapped up the magnetic (Fe1-xMgx)O·Fe2O3 catalyst to form the 3D CNT/(Fe1-xMgx)O·Fe2O3 with the high-performance of microwave absorption. The maximum absorption of the three-dimensional carbon nanocomposites at 11.8 GHz with a thickness of 2.0 mm is −37.3 dB. The coupling of dielectric loss of CNTs and magnetic loss of (Fe1-xMgx)O·Fe2O3 results in the enhancement of microwave absorption. Therefore, this study provides a low-cost and green route to design the efficient catalyst for carbon nanotubes as well as high-performance absorbing materials. •MgO reduces the decomposition temperature of Fe2O3 and hindering the aggregation of catalyst formed during the CVD process.•The iron-based oxide can catalyze the growth of rich three-dimensional CNTs in situ at a low cost in the CVD method.•In-situ synthesis of high-efficiency microwave absorption 3D CNT/(Fe1-xMgx)O•Fe2O3 material with magnetic catalyst.