Nanocomposites Fe/Activated Carbon/PVA for Microwave Absorber: Synthesis and Characterization

Abstract

Nanocomposites, activated carbon/polyvinyl alcohol (AC/PVA) filled with Fe to form Fe/AC/PVA, were characterized by using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and vector network analyzer (VNA). The crystal orientations from Fe are (104), (110), and (200) and the bonding formations of AC are O-H, C-H, and C=C show existence in nanocomposites, which may be due to the Fe that has been filled the pore of AC via a chemical bond. 20% AC (3 mm in thickness) in nanocomposites shows higher performance absorption for C-band (4.65 GHz) with maximum reflection loss of −32.5 dB.

Structural properties and bonding characteristics of honeycomb structure of composite ZnMnO2 and activated carbon

“…It is indicated that the thickness increases the reflection loss and the level of absorption of electromagnetic waves. Dai et al 23 and Abdullah et al 24 reported that reflection loss (R) values less than −10 dB can be designed to attenuate electromagnetic waves. In this study composite honeycomb structure based on ZnMnO 2 derived from the waste of the conventional battery and AC for the thickness 6 mm shows the best performance of absorption of electromagnetic waves for frequency 4–5 GHz and shows promise as a new type of electromagnetic wave absorber material.…”

Decreasing charge recombination by magnetic trap of iron‐carbon (Fe‐AC) composite for enhanced photocatalytic performance

“…The interband transition state in low loss region indicated surface state and the bandgap that are the most important parameter for photocatalytic application can be determined by using reflection electron energy loss (REELS) spectroscopy and the chemical state can be obtained from the core level of Fe 2p, O 1s, and C 1s by using X‐ray photoelectron spectroscopy (XPS). The validity of REELS and XPS spectrum in determining the bandgap and chemical state 24–30 has been reported in various kind of materials including transparent oxide films and composites, 16–18,23 metals and their alloys, 28,29 dielectrics materials, 24,27 and semiconductors 25,26 …”

“…For photo‐catalytic application, the radiation is used as a source in increasing catalytic activity, some of the oxygen atom at the surface of carbon atom having an energy for breaking the bond. The oxygen loss from the carbon is used for bonding with Fe atoms to form Fe–O 16–19 . Activated carbon (AC) is also having high porous structure due to the high surface area with excellent adsorption capacity.…”

“…For photocatalytic applications, the charge inside the pore by the oxidation or by the redox reaction will produce radical atoms to be easily sitting in the site of the pollutant molecule and breaking another bond from the inside of the pollutant molecule to accelerate the degradation efficiency 13,14 . In our previous study, we have used the pore of AC for electromagnetic wave absorber applications in combination with ionic state Fe 3+ in the form of composite Fe 3 O 4 ‐AC 23 and Fe‐AC 17 . For the present study, we use composite Fe‐AC 17 as a magnetic trap of the charge particle for enhanced photocatalytic performance of organic dye.…”

“…It is fortunate that the iron oxide bandgap adjusted by modifying the electronic, structural, magnetic, and absorption properties through the doping or co‐polymerization 23 . In our previous study for electromagnetic wave absorber applications, we determine the crystallite size only by Scherer method, analysis of bonding vibration from FTIR spectra, and microwave absorber properties 17 . In this study, we continue for characterization of the chemical state, electronic properties (including band gap), structural properties, magnetic properties, absorption, and photocatalytic performance of composite Fe‐AC.…”