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Microwave-activated reduced graphene oxide composite with hydrothermally treated corn husk activated carbon as an active electrode for high electrochemical performance in symmetrical carbon-based supercapacitor devices
(2026-07-01)
Srakaew, Khattiya
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Ratchayotee, Pornthip
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Janorat, Phattharawadee
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Phrompet, Chaiwat
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Kitiwan, Mettaya
This work applies microwaves for synthesizing reduced graphene oxide (rGO) and waste material corn husk activated carbon composites as active electrode materials for symmetric supercapacitors. The rGO is activated by microwave treatment and corn husk carbon by KOH in processed hydrothermal activation, followed by compositing at various weight ratios. Among all compositions, rGO:H_Corn_C (90:10) is reported with the best properties, with a specific surface area of 314.2 m2/g and a high specific capacitance of 1152 F/g at 0.1 A/g. The optimized composite also delivered increasing energy and power densities of up to 160 Wh/kg and 9.68 × 102 W/kg, respectively, within a 1 V operating window. In an experiment by assembling a symmetric coil cell supercapacitor, the device showed a specific capacitance of 142.23 F/g at 0.1 A/g, cycling stability with 98.8% capacitance retention after 1000 cycles of charge-discharge, and peak energy and power densities of 40.68 Wh/kg and 5.74 × 102 W/kg. Overall, the composite material with a high content of rGO and corn husk-derived activated carbon prepared by the hydrothermal method exhibits high-performance for the material in supercapacitor applications.
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Effect of rGO nanosheet loading in SiO2/rGO hybrid nanocomposites for enhancing optoelectrical, physical, and electrochemical properties
(2025-05-01)
Khammahong, Sunisar
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Sriwong, Chaval
In this study, silicon dioxide nanoparticles (SiO<inf>2</inf>NPs) mixed with reduced graphene oxide nanosheets (rGONS) and hybrid nanocomposites (S/rGOHNCs) were synthesized to study the opto-electrical, physical and electrochemical properties. S/rGOx%HNCs samples with rGONS at various loadings (10, 30, 50, and 70 wt%) were prepared SiO<inf>2</inf>NPs and rGONS suspensions in ultrasonication process by conventional heating. The SiO<inf>2</inf>NPs, rGONS and S/rGOx%HNCs were characterized and properties confirmed by XRD, Raman spectroscopy, FT-IR spectra, UV–Vis, SEM, EDX and TGA techniques. The electrical conductivity carrier concentration, energy gap, and dielectric constant increased with rGONS loading. The S/rGO30HNCs exhibited the highest thermal conductivity, 0.7 W/m·K, and Vickers microhardness, 41.0 HV. The value of electrochemical capacity of S/rGO70HNCs, 66.95 F/g, was due to the appropriate ratio of rGONS and SiO<inf>2</inf>NPs which significantly contributed to increasing redox reaction. The findings offered SiO<inf>2</inf>NPs mixed rGONS hybrid nanocomposites with enhanced optoelectrical (electrical, optical, dielectric), physical (mechanical, thermal) and electrochemical properties.
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Synthesis and electrochemical properties of activated lignite carbons-reduced graphene oxide nanocomposites symmetric supercapacitors
(2024-08-15)
Tuichai, Wattana
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Karaphun, Attaphol
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Phrompet, Chaiwat
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Chanlek, Narong
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Swatsitang, Ekaphan
Ultra-fast chargeable or rechargeable symmetric carbon-based supercapacitors (SCSs) with high capacity, inexpensive, and non-flammability have attracted much attention for electronics and energy storage devices. However, improving both high redox reaction and ion transport/diffusion processes by enhancing high energy storage performance and rapid ion/electron transport SCSs electrode materials remains challenging. Herein, we presented a successful preparation of activated lignite carbons-reduced graphene oxide (ALC-rGO) nanocomposite (NCp) with the ALC:rGO ratio of 80:20 wt% by a one-pot hydrothermal for high electrochemical performance. Importantly, the matrix of ALC-rGO NCp was primary amorphous carbon with hexagonal graphitic layers and pore structures of plentiful micropores and mesopores. Remarkably, the ALC-rGO NCp electrode exhibited a maximum specific capacitance (C<inf>sc</inf>) of 152.12 F/g at 0.5 A/g. Interestingly, the SCSs-ACL-rGO device could illustrate a good performance at a potential voltage of 1.8 V with C<inf>sc</inf> of 50.90 F/g at 1 A/g and capacity retention of 96.0 % at 5 A/g after 2,000 cycles GCD test.
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Fabrication and thermoelectric conversion of thermoelectric concrete brick with buried unileg N-type CaMnO3 thermoelectric module inside
(2023-12-01)
Maneesai, Keerati
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Khammahong, Sunisar
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Siripoom, Pongsakorn
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Phrompet, Chaiwat
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Sriwong, Chaval
To investigate the effect of heat loss reduction due to thermal insulator and thermal interface resistance due to multi-layer structure in order to improve the efficiency of a thermoelectric device, a thermoelectric concrete brick was fabricated using a unileg n-type CaMnO<inf>3</inf> thermoelectric module inside. CaMnO<inf>3</inf> thermoelectric materials were synthesized by starting materials CaCO<inf>3</inf> and MnO<inf>2</inf> to produce a unileg n-type CaMnO<inf>3</inf> module. Thermoelectric concrete brick consisted of two types: I-layer brick (one layer of concrete thermal insulator) and III-layer brick (three layers of different concrete insulators). The occurring temperature difference, electric current and voltage on the CaMnO<inf>3</inf> module and thermoelectric concrete brick were measured in closed and open circuits. The temperature difference, thermal distribution, and output voltage when applying constant temperatures of 100, 200 and 400 °C were measured. Computer simulations of the Finite Element Method (FEM) were performed to compare with the experimental results. The trends of the temperature difference and the output voltage from the experimental and computer simulations were in good agreement. The results of the temperature difference during the hotter side temperature of 200 °C exhibited the temperature difference along the vertical direction of the thermoelectric concrete bricks for both types of the III-layer brick of 172 °C and the I-layer brick of 132 °C are larger than that of the CaMnO<inf>3</inf> TEG module without using a thermal concrete insulator of 108 °C. The thermoelectric concrete bricks of the III-layer brick type of 27.70 mV displayed output voltage results being higher than those of the I-layer brick of 26.57 mV and the CaMnO<inf>3</inf> TEG module without using a thermal concrete insulator of 24.35 mV. Thermoelectric concrete brick of the III-layer brick type displayed higher electric generation power than the I-layer brick and the CaMnO<inf>3</inf> TEG module. Additionally, the results exhibited the capability of thermoelectric concrete brick in the III-layer brick model for electric generation power based on the temperature difference. The TEG concrete brick of I-layer concrete covering the series–parallel combination circuit of 120 modules of the unileg n-type CaMnO<inf>3</inf> was constructed and then embedded on the outer surface of the furnace. During the maximum hotter side temperature of 580 °C of the concrete brick, the temperature difference between the hotter side and the cooler side of the brick occurred at 365 °C and the maximum output voltage was obtained at 581.7 mV.
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Temperature-dependent electrical transport, Hall effect, and Seebeck properties of bulk chemically reduced graphene oxide with bipolar charge carrier materials
(2023-03-01)
Maneesai, Keerati
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Silakaew, Kanyapak
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Khammahong, Sunisar
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Phrompet, Chaiwat
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Sriwong, Chaval
The temperature-dependent electrical transport, Hall effect, and Seebeck properties of bulk-reduced graphene oxide (rGO) prepared by a chemical reduction process were investigated in a temperature range of 310-475 K. The bulk rGO contained bipolar charge carriers with p-type to n-type switching at a temperature of 420 K. The materials illustrated a p-type characteristic in the temperature range of 310-420 K and n-type characteristic in the temperature range of 420-475 K. The charge transport mechanism was that of the graphene-derived 2D material in the p-type regime and governed by polaronic charge carriers.
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Enhancing the hydrogen permeation of alumina composite porous membranes via graphene oxide addition
(2023-01-12)
Hankoy, Montree
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Kaewpengkrow, Prangtip Rittichote
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Vichaphund, Supawan
Graphene oxide (GO) membranes have attracted considerable interest for hydrogen (H<inf>2</inf>) purification applications. However, the addition of GO into matrix materials to enhance the efficiency of H<inf>2</inf> permeation remains a challenge. In this study, the fabrication of alumina/graphene oxide (AGO) composites containing varying contents of GO (0.5–3.0 wt.%) was investigated. The AGO composites were formed into pellets and sintered for 2 h at 1500 °C. Accordingly, the presence of GO in the membranes following sintering was confirmed by Raman spectroscopy. Additionally, the porosity of the AGO composites increased from 3.7% to 26.9% as the GO concentration increased from 0.5 wt.% to 3.0 wt.%. Furthermore, the average pore diameter of the AGO composites was in the range of 87–228 nm, and the pore size distribution was unimodal. The performance of the AGO membranes was investigated for the permeance of single gases H<inf>2</inf> and N<inf>2</inf> at 30–500 °C to evaluate their potential for H<inf>2</inf> separation applications. The AGO membranes with a GO addition of 2.5 and 3.0 wt.% exhibited a high hydrogen permeance of 232–410 × 10−6 mol m−2 s−1 Pa−1, which was approximately 10 times greater than that of pristine Al<inf>2</inf>O<inf>3</inf> membrane. Additionally, the ideal H<inf>2</inf>/N<inf>2</inf> selectivity values ranged from 4.02 to 4.20. Furthermore, gas permeation through the AGO membrane was observed to follow the Knudsen diffusion mechanism.
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The Mechanical and Thermal Properties of Cement CAST Mortar/Graphene Oxide Composites Materials
(2022-12-01)
Janjaroen, Thidatip
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Khammahong, Sunisar
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Tuichai, Wattana
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Karaphun, Attaphol
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Phrompet, Chaiwat
This paper presents the influence of the graphene oxide (GO) sheet contents at conditions of 0, 0.01, 0.03, 0.05, and 0.1 wt% on the mechanical and thermal properties of GO/CAST 11 LW mortar (GMT) composites for heat insulating brick. The GMT composites were prepared by a simple mixing method. The structure of GMT composites was investigated by X-ray diffraction (XRD) and Raman spectroscopy (Raman) techniques. The small grain sizes of GMT composites were confirmed by transmission electron microscopy (TEM). The mechanical properties of GMT composites are increased with increasing GO contents. A lot of functional groups in GO such as carboxylic acid reacted with a calcium silicate hydrate, CaH<inf>2</inf>O<inf>4</inf>Si (CSH), calcium hydroxide, Ca(OH)<inf>2</inf> (CH) and Ettringite, and Ca<inf>6</inf>[Al(OH)<inf>6</inf>]<inf>2</inf>(SO<inf>4</inf>)<inf>3</inf>·26H<inf>2</inf>O (CA) phases in the mortar, which can be considered good mechanical properties in the GMT composites. The heat insulation values of GMT composites were improved by the interaction with the CSH, CH, and CA phases in the cement mortar on the surface of GO. The highest compressive and tensile strengths and low heat transfer rate of about 0.465 W/min were observed at 0.05 of GO (GMT_0.05) composites in the curing age of 7 days. Thus, a new pathway of GMT composites can be prepared by a simple mixing method to significantly improve the mechanical and thermal properties of mortar GMT composites.
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Hydrogen Sulfide Adsorption on Alumina/Graphene Oxide Composites at Ambient Temperature
(2022-11-01)
Hankoy, Montree
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Kitiwan, Mettaya
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Kaewpengkrow, Prangtip Rittichote
Hydrogen sulfide (H<inf>2</inf>S) is one of the most common pollutants found in natural gas and industrial waste. Over the few decades, the removal of H<inf>2</inf>S has become a significant problem. In the field of a clean environment such as water purification and toxic gas removal, graphene oxide (GO) has been found to have advantages. In this study, the influence of GO on alumina (Al<inf>2</inf>O<inf>3</inf>) as an adsorbent of H<inf>2</inf>S was examined. A series of Al<inf>2</inf>O<inf>3</inf>/GO (AGO) composites with varying graphene oxide addition (0.5–3.0 wt%) were prepared using the high-temperature sintering method. The X-ray diffraction patterns indicate the primary phase of Al<inf>2</inf>O<inf>3</inf> with hexagonal crystal structure for all AGO composites. Raman spectrometry measurements confirmed that the GO particles were incorporated in AGO composites. The TEM image indicated that GO nanosheets were embedded between Al<inf>2</inf>O<inf>3</inf> grains. The efficiency of AGO adsorbent at ambient temperature was investigated and compared with the pristine Al<inf>2</inf>O<inf>3</inf> adsorbent. The AGO composites adsorbent demonstrated the H<inf>2</inf>S breakthrough capacity in the range of 0.07–0.43 mg/g, which is higher than that of pristine Al<inf>2</inf>O<inf>3</inf> (0.06 mg/g). Furthermore, the highest H<inf>2</inf>S breakthrough capacity of 0.43 mg/g was obtained from AGO containing 3.0 wt% GO. This investigation demonstrates that the AGO adsorbent fabricated using a simple method has the potential to be used for H<inf>2</inf>S removal at ambient temperature.
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Characterization and electrochemical properties of CuO–Cu2O@rGO nanocomposite synthesized by a seed-mediated growth process
(2022-04-01)
Wongjom, Poramed
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Tuichai, Wattana
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Karaphun, Attaphol
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Phrompet, Chaiwat
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Daengsakul, Sujittra
A CuO–Cu<inf>2</inf>O@rGO nanocomposite (CuO–Cu<inf>2</inf>O@rGO NCP) has been successfully prepared through a seed-mediated growth process. X-ray diffraction (XRD) analysis results indicated a monoclinic phase of CuO–Cu<inf>2</inf>O@rGO NCP with space group C2/c. Transmission electron microscopy (TEM) revealed agglomeration of the CuO and Cu<inf>2</inf>O nanoparticles in the rGO sheet matrix. The interaction of CuO–Cu<inf>2</inf>O@rGO NPC resulted from the aggregation and overlapping of CuO and Cu<inf>2</inf>O nanoparticles owing to the influence of a seed-mediated growth process. The electrochemical properties of the CuO–Cu<inf>2</inf>O@rGO NPC electrode indicate the storage of energy at the surface through a pseudo-capacitive mechanism. The specific capacitance at a current density of 0.5 A g−1 and the average percentage capacity retention after 1000 cycles of a CuO–Cu<inf>2</inf>O@rGO electrode at a current density of 10 A g−1 were evaluated as 125.54 F g−1 and 89.87 ± 3.30%, respectively. In the CuO–Cu<inf>2</inf>O@rGO electrode, the incorporated rGO affects the electrical conductivity and the synergistic interactions in charge–discharge processes. Interestingly, these results showed that the material was synthesized through a seed-mediated growth process and reveal the key factors that determine the combination and volume expansion of the reversible redox transition between Cu+ and Cu2+ during charge–discharge processes.
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Influence of free electron charge and free extra framework anions in calcium aluminate@ rGO (CA@ rGO) cement composites with enhanced dielectric and electrochemical properties
(2021-10-01)
Ruttanapun, Chesta
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Phrompet, Chaiwat
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Tuichai, Wattana
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Karaphun, Attaphol
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Daengsakul, Sujittra
Nowadays, the metal oxide-based composites loaded with reduced graphene oxide (rGO) nano sheets are believed to enhance both the electrochemical and dielectric properties. In this study, therefore, the effect of rGO loading contents on the calcium aluminate (CA), namely CA@ rGO, cement composites with high dielectric and electrochemical properties is presented. CA@ rGO composites were successfully synthesized via a simple direct mixing of CA cement with various contents of graphene oxide (GO) precursors followed by a conventional thermal reduction method. Based on XRD and Raman spectroscopy results, all prepared CA@ rGO composites clearly confirmed both the structure of the pristine CA cement as well as the complete conversion of GO precursors to rGO after thermal reduction, and the existence of rGO nano sheets on the surface of CA@ rGO composites. The impedance value results revealed that the enhancement of a high dielectric constant was achieved in the CA@ rGO composites due to both typical interface polarization and the micro-capacitor of CA cement and rGO nano sheets. Meanwhile, the prepared CA@ rGO-4 composite electrode exhibited the highest of electrochemical double-layer capacitive behavior with the specific capacitance (C<inf>sc</inf>) value of 79.33 F g−1 at 0.2 A g−1. The enhanced super-capacitive performance of CA@ rGO composite can be improved by the synergistic effect of free electron transfer and electron diffusion between the CA cement interface and rGO nano sheets.

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