Cerium oxide immobilized reduced graphene oxide hybrids with excellent microwave absorbing performance

Abstract

Microwave absorbing materials with high absorption over a broad bandwidth when they have a small thickness are strongly desired due to their widespread applications. Herein, cerium oxide immobilized reduced graphene oxide (CeO2-rGO) hybrids with excellent microwave absorbing performance have been fabricated by a versatile one-step hydrothermal approach. Modern measurement techniques, including X-ray diffraction, Raman spectroscopy, electronic microscopy, X-ray photoelectron spectroscopy and vector network analysis, have been conducted to characterize the chemical composition, microstructure and electromagnetic performance of the as-obtained hybrids. Morphological analysis reveals that the CeO2 nanocrystals are homogeneously immobilized onto the rGO surface without any significant agglomeration. Interestingly, significant enhancement in the microwave absorbing performance has been observed for all the CeO2-rGO hybrids. For example, a CeO2-rGO hybrid with a 10 : 1 mass ratio of CeO2 to GO exhibits a minimum reflection loss (RL) of -45.94 dB, which is 73.35 times and 6.14 times that of the lone CeO2 and rGO, respectively. Moreover, the CeO2-rGO hybrid shows a broadband absorption feature with an effective absorption bandwidth (RL < -10 dB) of 4.5 GHz, and can be exploited for practical application in a frequency range of 3.68-18.00 GHz via tuning of the thickness. Investigation of the structure-property correlation indicates that such enhancements are attributed to conductive loss, polarization loss and multiple reflections which are mainly derived from the unique CeO2-rGO based architecture. In addition, the higher oxygen vacancy concentration of CeO2 in hybrids can promote electron transfer between CeO2 and rGO, leading to microwave attenuation enhancement. It is expected that these CeO2-rGO hybrids can be used as new microwave absorbers.

Evaluation of the Cytotoxicity and Oxidative Stress Response of CeO2-RGO Nanocomposites in Human Lung Epithelial A549 Cells

“…The average crystallite sizes of CeO 2 NPs and CeO 2 -RGO nanocomposites were estimated by Scherrer's formula, using the prominent peak (111), and it was found to be around 18 and 16 nm for CeO 2 NPs and CeO 2 -RGO nanocomposites, respectively. Our XRD data on RGO, CeO 2 NPs, and CeO 2 -RGO nanocomposites were according to earlier reports [36,37]. estimated by Ellman's procedure, using 5,5-dithio-bis-nitrobenzoic acid (DTNB) [33].…”

“…The XPS spectra of C1s given in Figure 2B contain a non-oxygenated aromatic sp 2 bonded carbon ring (C-C) at 286.5 eV [39]. Figure 2C represents the O1s spectra of CeO2, with two intense peaks at 530.9 and 536.8 eV, linked with anionic oxygen in CeO2 and the presence of the residual oxygen functional group in the RGO sheets, respectively [37]. The morphologies of the CeO2 NPs, RGO, and CeO2-RGO nanocomposites were further characterized by SEM and TEM ( Figure 3A-F).…”

MOF Induces 2D GO to Assemble into 3D Accordion‐Like Composites for Tunable and Optimized Microwave Absorption Performance

“…The D band and the G band located at 1334.1 and 1588.9 cm −1 for RGO, 1337. 5 [38] The integrated area ratio (I D /I G ) of these two peaks varied from 1.53 to 1.77 ( Figure 4b), which may be attributed to more numerous defects created during the combination of CeO 2−x and RGO. [39][40][41] Importantly, these defective sites which would induce charge polarization relaxation were deeply related to the MA performance.…”

“…[30] Wang et al fabricated RGO/CeO 2 composites which showed enhanced MA performance. [31] Gao et al synthesized a series of 2D carbonbased nanocomposites with the loading of cerium oxide and other types of rare earth oxides with tunable and ultra-efficient MA properties. [32] These studies guide us to tune the correlative electromagnetic properties of composite by simply regulating one of the two components.…”

Performance enhanced electromagnetic wave absorber from controllable modification of natural plant fiber

“…6,7 For years, researchers have been focusing on developing light weight and effective absorber with strong reection loss and broad absorbing bandwidth. 8,9 In the last few years, various carbonaceous materials have always been ideal candidates for EMW absorbing materials due to their controllable structure and properties. Particularly, graphene oxide (GO), carbon nanotubes (CNT), as well as their derivatives, have made great progress as precursors of EMW absorbing materials.…”