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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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The Impact of Incorporating Reduced Graphene Oxide Quantum Dots into KOH Electrolyte on the Electrochemical Performance of Supercapacitors Using Sugarcane Bagasse Active Electrodes
(2025-09-30)
Panturotai, Kuwalai
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Sriwong, Chaval
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Ruttanapun, Chesta
This study used reduced graphene oxide quantum dots (rGO-QDs) to enhance the ionic conduction and specific capacitance of the sugarcane bagasse carbon active electrode in a supercapacitor. The rGO-QDs solution was mixed with the KOH electrolyte at 0.5, 1.0, 3.0, and 5.0% by weight (rGO-QDs-X%/6M-KOH). The sugarcane bagasse-activated carbon (SAC) was prepared from sugarcane bagasse (SB) waste through activation by annealing in an argon atmosphere and ground in a high-speed three-dimensional (3-D) ball mill (AC3D-SAC). The rGO-QDs were synthesized and verified by high-resolution transmission electron microscopy (HRTEM), which showed that the size of the rGO-QDs was less than 10 nm. Raman spectroscopy displayed peaks of the D-band and G-band. The rGO-QDs-3%/6M-KOH electrolyte exhibited the highest ionic conductivity, 26 mS/cm. The AC3D-SAC active carbon had a specific surface area of 915.57 m2/g. The active electrodes made with AC3D-SAC and rGO-QDs-3%/6M-KOH for the half-cell electrode showed the highest specific capacitance of 176.83 F/g at 0.5 A/g. The working electrode symmetric supercapacitor coin cell device, using the rGO-QDs-3%/6M-KOH electrolyte, achieved a maximum specific capacitance of 54.53 F/g at 0.5 A/g. These results were twice as high as those with the KOH electrolyte alone. The efficiency retention of the coin cell dropped to 90% after 5000 cycles. The supercapacitor demonstrated impressive electrochemical performance with high ionic conduction and capacitance, thanks to the rGO-QDs/6M-KOH electrolyte and the large surface area of the AC3D-SAC active carbon. The findings confirmed that adding rGO-QDs to the KOH electrolyte improved the electrochemical performance of the symmetric supercapacitor device.
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A flow-circulation system incorporating a PVP-BiOBr@rGO assembly for simultaneous degradation and detection of oxytetracycline in fish farm wastewater
(2025-05-27)
Teerasong, Saowapak
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Suknakhin, Nichakarn
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Sonsaket, Thanamat
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Teerasong, Wanatchaporn
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Ruttanapun, Chesta
This work focuses on developing a new flow-circulation system for simultaneous detection and degradation of oxytetracycline (OTC) in fish farm wastewater to address a need for antibiotic abatement in wastewater treatment. Polyvinyl pyrrolidone capped bismuth oxybromide assembled with a reduced graphene oxide (PVP-BiOBr@rGO) photocatalyst was solvothermally synthesized and characterized. The prepared photocatalyst exhibited a morphological flower-like structure with a high surface area, 47.59 m2 g−1. Its band gap energy was 2.93 eV. A ternary PVP-BiOBr@rGO composite showed lower charge recombination than its pure form. PVP-BiOBr@rGO was filled inside a catalyst column of a flow system, with a spectrophotometer at the column end. Wastewater was continuously transported through the column and OTC spectrophotometrically examined during its degradation. The wastewater was recirculated until the OTC concentration was minimized. This system achieved 90.3% degradation of OTC within 180 min. The catalyst column could be regenerated for 2 cycles. The proposed flow system offers the advantages of ease of use, inline operation, and real-time sensing. This highlights a potential for real-world sustainable wastewater treatment 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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Fabrication, optical and ion conduction properties of reduced graphene oxide quantum dots and application in electrolyte supercapacitor devices
(2025-05-01)
Seesan, Tanatchaya
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Sriwong, Chaval
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Ruttanapun, Chesta
Reduced graphene oxide quantum dots (rGO-QDs) were synthesized via the hydrothermal method and characterized for their structural, optical, and ion conduction properties. Raman spectroscopy confirmed a low defect density (I<inf>D</inf>/I<inf>G</inf> ratio: 0.91), while X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed reduced interlayer spacing and particle sizes (∼4.14 nm), indicative of quantum confinement effects. Optical analysis demonstrated tunable photoluminescence and strong absorption, confirming their quantum dot nature. Electrochemical impedance spectroscopy (EIS) highlighted enhanced ionic conductivity and reduced internal resistance in supercapacitor devices utilizing KOH/rGO-QDs electrolytes, improving specific capacitance and ion transport. These results establish rGO-QDs as promising materials for optoelectronics and energy storage applications, particularly in high-performance supercapacitors.
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Enhancing electrochemical properties of an activated bamboo carbon-based supercapacitor with reduced graphene oxide nanocomposites through pulverizing and mixing in a 3-D high-speed ball mill
(2025-04-01)
Srichaiprapha, Kitima
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Ruttanapun, Chesta
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Sriwong, Chaval
Bamboo-activated carbon (AC-BBC) achieved improved electrochemical properties by compositing it with reduced graphene oxide (rGO) at 1, 3, 5, and 7% weight (wt%). The AC-BBC samples were prepared by annealing bamboo carbon (BBC) powder and a KOH mixture through flowing argon at 900 °C. It was pulverized and mixed using high-speed three-dimensional (3-D) ball milling. rGOx%/3D-AC-BBC (x = 1, 3, 5, and 7 wt%) samples, which are referred to as AC-BBC composites with x% rGO ground by 3-D ball milling, were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy techniques. Analysis using scanning electron microscopy (SEM) and specific surface area (SSA) revealed that the rGO5%/3D-AC-BBC sample exhibited the highest specific surface area (SSA), 2239.80 m²/g, with an average pore size of 2.22 nm. Half-cell electrodes had the greatest specific capacities, 301.80 F/g at 0.5 A/g. The symmetric supercapacitor coil cell device showed a capacitance of 85.93 F/g, an energy density of 11.93 Wh/kg, and a power density of 49.56 W/kg. The efficiency retention was reduced to 96.76% after 10,000 cycles. This manuscript presents a high-performance rGO5%/3D-AC-BBC material that can be used for active electrodes to enhance electrochemical properties, making them suitable for electric double-layer capacitor (EDLC) applications.
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Development of functional construction materials from cement–reduced graphene oxide composite capable of generating electricity with improved mechanical strength
(2024-09-01)
Sintusiri, Jirapan
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Hongsrichan, Pemika
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Boonsri, Phanupong
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Tongjune, Phitthayathon
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Sriwong, Chaval
In this work, we have developed a functional construction material from a cement material that can scavenge mechanical energy from surrounding environment into electricity. An energy harvesting device called “a triboelectric nanogenerator (TENG)” is fabricated from the cement–reduced graphene oxide (rGO) composite to convert mechanical energy into electrical power. The incorporation of rGO in cement is found to enhance the electrical output of the TENG through space charge polarization, resulting in the increase in triboelectric charge density. The maximum power density achieved from the cement–rGO composite TENG is 1.72 W/m2, which is six times greater than that of the unmodified cement TENG. Additionally, rGO improves the compressive strength of the cement composite by up to 50%. This enhancement is attributed to the large specific surface area of rGO, which creates nucleation sites, resulting in increased crystallization of cement hydration products. The findings of this work highlight the promising prospects for the development of functional construction material for smart energy building with improved mechanical strength. Graphical abstract: (Figure presented.)
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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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Effecting on electrical performance of Methylammonium Lead Chloride Iodide perovskite films composited by reduced graphene oxide for controlling double Schottky barrier
(2024-06-01)
Butsriruk, Kwanruthai
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Sriwong, Chaval
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Ruttanapan, Chesta
Semiconducting perovskite thin films are cheap to fabricate and can be coated on fluorine-doped tin oxide (FTO) substrates by using simple techniques such as the solution deposition method. In this work, we show that the improved electrical performance of perovskite film produces that of single crystals in an ambient atmosphere. Herein, Methylammonium Lead Chloride Iodide (MAIPbCl<inf>2</inf>) is played as perovskite films, which were composited with different weight percent (wt%) of rGO from 7 to 10. All samples in this work were presented with physicochemical, electrical, and optical properties. However, the challenge of this work is the electron scattering at the grain boundaries as a result of the double schottky barrier. The best decreasing the double schottky barrier yielded a maximum conductivity of 68.72 ± 0.95 S/cm, a low sheet resistance of 5.47 ± 1.64 Ω, a decrease in the lowest oxygen vacancy, and an increase in the grain size from 27.89 nm (of MAIPbCl<inf>2</inf>) to 34.96 nm at room temperature for the MAPbCl<inf>3</inf>-8 wt% rGO composite, which also revealed that this strategy significantly helped to improve the performance of the film. Furthermore, temperature dependence for MAIPbCl<inf>2</inf>-rGO composites demonstrates this high electrical conductivity from room temperature to 323 K, with highest electrical conductivities of 78.68 ± 0.01 S/cm and the activation energy of 0.18 eV at 313 K for 8 wt% rGO. Therefore, MAIPbCl<inf>2</inf>-rGO composite films demonstrated the enhancement of performance of MAIPbCl<inf>2</inf> films; this is next promising for perovskite films in the future.
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Grain boundary, electrical transport and thermoelectric properties of the ultra-high rGO amount of C12A7-rGO composites
(2024-04-30)
Maneesai, Keerati
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Thongkam, Montree
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Sriwong, Chaval
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Ruttanapun, Chesta
The Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> ceramic (C12A7) and reduced graphene oxide (rGO) composite which an ultra-high amount (i.e., 40, 50, 60, and 70 wt%) of rGO (ultra-high amount C12A7/rGO composite) were synthesized by a solid-state reaction process. After the hydraulic press, the heat treatment in the temperature range of 773 K under the argon environment had been performed with the composite pellets for 30 min. XRD results of the C12A7 and all the ultra-high amount C12A7/rGO composites indicated a pure phase of C12A7 ceramic. Raman spectra confirmed the existence of rGO content in all the ultra-high amount C12A7/rGO composites. Raman peaks also suggested reduction of the free O<inf>2</inf>2− and O<inf>2</inf>− ions from the framework of the ultra-high amount C12A7/rGO composites. SEM image presented the homogeneous grain boundary interface after the heat treatment at 773 K of the C12A7 wrapped by the rGO sheet, the agglomerated rGO sheet, and the rough interface stack of rGO sheets. UV-VIS spectroscopy presented the absorption behavior, direct energy gap, and indirect energy gap modifications of the ultra-high amount C12A7/rGO composites. Electrical conductivity of the ultra-high amount C12A7/rGO composites illustrated larger than 108 times improvement with temperature independence. Range of −5 to −17 μV/K, temperature dependence, and increased with rGO content increasing Seebeck coefficient were reported. Thermal conductivity of the ultra-high amount C12A7/rGO composites was increased with the rGO content increasing. Both the Power factor (PF) and the figure of merit (ZT) of the ultra-high amount C12A7/rGO composites were temperature dependent and were increased with the rGO content increasing, within the range of 0.4 μW/m.K2 of PF and the range of 3x10−4 of ZT, respectively. These experimental results verified grain boundary, modified energy band, electrical transport properties and thermoelectric properties of C12A7/rGO composites loading with ultra-high content rGO

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