Facial Synthesized Co-doped SnO2@Multi-Walled Carbon Nanotubes as an Efficient Microwave Absorber in High Frequency Range

Abstract

Co-doped SnO2@multi-walled carbon nanotubes (MWCNTs) were fabricated by a one-pot hydrothermal process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution electron microscopy, and X-ray photoelectron spectroscopy (XPS) were employed to characterize the morphology and structure of the composites. XRD, FT-IR, and XPS analyses demonstrated that Co was doped into SnO2 lattice, no other impure phases were detected. Co-doped SnO2, with a uniform size of 4–6[Formula: see text]nm, is coated on MWCNTs but separated from the nanotubes with some aggregation. The microwave absorption properties of Co-doped SnO2@MWCNTs were investigated at room temperature within 2–18[Formula: see text]GHz. Results indicated that Co-doping concentration plays an important role in the microwave absorption capability of Co-doped SnO2@MWCNTs. The maximum reflection loss (RL) is [Formula: see text]22.8[Formula: see text]dB at 14.1[Formula: see text]GHz. The absorption bandwidth with RL less than [Formula: see text]10[Formula: see text]dB is 4.2[Formula: see text]GHz (12.2–16.4) with coating thickness of only 1.5[Formula: see text]mm; hence, Co-doping can enhance the microwave absorption performance of SnO2@MWCNTs. The excellent microwave absorption performance may be attributed to interfacial polarization, conductivity loss, and changes in electromagnetic parameters and lattice constant caused by Co-doping. Consequently, Co-doped SnO2@MWCNTs can be considered as efficient microwave absorbers in high-frequency range.