Sriwong, Chaval

Preferred name

Sriwong, Chaval

Main Affiliation

School of Science

chaval.sr@kmitl.ac.th

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Synthesis of reduced graphene oxide quantum dots from graphene oxide via hydrothermal process and theirs structural, luminescence and magnetic properties
(2023-01-01)
Buatong, Nattha
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Ruttanapun, Chesta
;
Sriwong, Chaval
Background: Reduced graphene oxide quantum dots (rGO-QDs) have attracted much interest because of its exceptional chemical and physical properties and novel applications in a new technology and devices such as, energy storage, electrochemical, photocatalysis, sensing, drug delivery, bioimaging and anticancer therapy. Methods: In this work, we reported a correlation study of the structural, morphological, luminescence and magnetic behavior of rGO-QDs as a function of hydrothermal reduction temperatures (such as 90 °C, 120 °C, 150 °C and 180 °C) of GO sheets precursor via hydrothermal process. GO precursor and the obtained rGO-QDs samples were confirmed and analyzed by several techniques such as, XRD, Raman, XPS, TEM, PL, UV–Visible, Fluorescence and EPR. Significant findings: Influence of hydrothermal cutting process with different temperatures (90 °C, 120 °C, 150 °C and 180 °C) on the evolution of structural, morphologies, luminescence and magnetic behavior for the changes of large GO sheets into ultra-small rGO-QDs is presented. XRD result confirmed the effect of increasing temperature on the hydrothermal cutting process which led to a decrease in D-spacing values of rGO-QDs products. While Raman results indicates the trend of I<inf>D</inf>/I<inf>G</inf> ratio decreases along with increasing hydrothermal reduction temperatures. XRS analysis revealed that the percentage of carbon content of GO precursor (∼64%) was shifted value to ∼83% for obtained rGO-QDs sample prepared at 180 °C. TEM images shown that a very thin plate-like shape with ultrasmall average diameter of rGO-QDs samples in rage of 22±2 nm to 8 ± 2 nm. The optical and PL results well-confirmed the characteristic quantum size effect of all rGO-QDs samples. Finally, the EPR signals indicate the crossover between paramagnetic and diamagnetic are depended on the reduction temperature. The rGO-QDs prepared at 180 °C do not give any EPR signal, signify the nonmagnetic nature. This indicate that the basal plane of rGO-QDs at 180 °C has nearly perfect sp2 network of graphene.
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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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Removal of methylene blue dye using metal-free g-C3N4 photocatalyst over natural sunlight irradiation
(2020-01-01)
Sriwong, Chaval
;
Choojun, Kittisak
This work presented the high activity of metal-free g-C<inf>3</inf>N<inf>4</inf> photocatalyst for methylene blue (MB) removing over natural sunlight irradiation. These g-C<inf>3</inf>N<inf>4</inf> photocatalysts materials were synthesized by a conventional thermal condensation method using melamine as a precursor under treated at the various annealing temperatures (450 °C, 500 °C, 550 °C, 600 °C and 650 °C). All assynthesized samples were characterized and confirmed by a several techniques, such as, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectrometer (DRS), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) specific surface area. XRD and FTIR results confirmed that the as-synthesized g-C<inf>3</inf>N<inf>4</inf> samples were completely synthesized at annealing temperature of 500 °C. SEM images showed the morphologies of the g-C<inf>3</inf>N<inf>4</inf> samples had more flake-like structures upon the increasing of annealing temperatures. WhileDRS results indicated that the absorption edges of as-synthesized g-C<inf>3</inf>N<inf>4</inf> samples were shifted to visible-light region, except the sample as-synthesized at 650 °C (g-C<inf>3</inf>N<inf>4</inf>-650 °C). Moreover, the photocatalytic properties of metalfree g-C<inf>3</inf>N<inf>4</inf> photocatalyst materials were evaluated by degrading of MB dye solution under natural sunlight irradiation for 100 min. The results revealed that the highest photocatalytic activity was exhibited by the sample synthesized at 600 °C, which the apparent rate constant (kapp.) was 0.0291min-1. The orders of activities as:g-C<inf>3</inf>N<inf>4</inf>-600°C > g-C<inf>3</inf>N<inf>4</inf>-650 °C > g-C<inf>3</inf>N<inf>4</inf>-550 °C > g-C<inf>3</inf>N<inf>4</inf>-500°C > g-C<inf>3</inf>N<inf>4</inf>-450°C. Hence, the metal-free g-C<inf>3</inf>N<inf>4</inf> photocatalyst appears to be an attractivematerial for water or wastewater purification applications over activated by sunlight irradiation.
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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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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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Immobilization of Silver Doped Titanium Dioxide onto Stainless Steel Wire Mesh for Photocatalytic Degradation of Gaseous Formaldehyde under Visible Light Irradiation
(2022-03-01)
Sriwong, Chaval
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Klypoo, Akekarat
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Khingram, Aiyakub
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Natluecha, Ratima
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Junyapoon, Suwannee
Titanium dioxide (TiO<inf>2</inf>) photocatalysis can degrade air pollutants into nontoxic substances but it can only be excited by UV light. To eliminate this limitation, silver (Ag) and/or graphene oxide (GO) doped TiO<inf>2</inf> are applied to enhance visible light photocatalytic activity. In this study, Ag-TiO<inf>2</inf> (0. 5%, 1%, 2% w/w), GO/TiO<inf>2</inf> and GO/Ag-TiO<inf>2</inf> were synthesized and then coated on stainless steel mesh. Crystalline and molecule structures, chemical compositions and optical properties of the prepared photocatalyst samples were characterized with X-ray diffraction spectroscopy, X-ray fluorescence spectroscopy, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, and Scanning electron microscopy equipped with Energy dispersive X-ray spectroscopy techniques. The photocatalytic performances of the various doped catalysts were evaluated according to their abilities to degrade gaseous formaldehyde (HCHO) under visible light. The effect of operational parameters on the photocatalytic degradation of HCHO including layer numbers of photocatalyst, powers of fluorescent lamp and flow rates of HCHO were observed. The results indicated that the presence of Ti, O and Ag elements in Ag-TiO<inf>2</inf> and Ti, O, Ag and C elements in GO/Ag-TiO<inf>2</inf> was confirmed. Proper dispersion of the photocatalyst on the wire mesh was exhibited. Under visible light, the incorporation of Ag and GO in TiO<inf>2</inf> photocatalysts produced higher degradation rates of HCHO than pure TiO<inf>2</inf>. The optimum operating conditions of HCHO degradation at initial concentration of 108.7±1.15 ppm over visible light irradiation for 30 min were 5 layers of 0.5% Ag-TiO<inf>2</inf>, 72 W fluorescent light and 300 ml/ min of HCHO flow rate. Under these conditions, the removal efficiency of gaseous HCHO was 76.70±0.73%.
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Two Steps for Improving Reduced Graphene Oxide/Activated Durian Shell Carbon Composite by Hydrothermal and 3-D Ball Milling Process for Symmetry Supercapacitor Device
(2023-10-01)
Ngamjumrus, Nantikron
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Silakaew, Kanyapak
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Thompho, Somphob
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Sriwong, Chaval
;
Ruttanapun, Chesta
Durian shell waste was used to fabricate activated carbon (AC) using a hydrothermal process and three-dimensional (3-D) ball milling. Reduced graphene oxide (rGO) was composited with activated durian shell carbon (DC) to enhance the electrochemical properties for fabricating a supercapacitor (SC) device. Scanning electron microscopic (SEM) examination of the AC from hydrothermally processed durian shell carbon (AC–HDC) and AC–HDC that was 3D ball milled for 15 min (rGO/AC–HDC–3D15M) showed compacted and uniformly distributed particles with good porosity. The rGO/AC–HDC–3D15M sample exhibited high specific surface area (SSA) using the Brunauer–Emmett–Teller (BET) methodology, 2311 m2/g, and an average pore size of 1.88 nm. Electrochemical results showed that the rGO/AC–HDC–3D15M sample had the highest specific capacitance (Cs) of 545.78 F/g, power density (Pd) of 260.834 W/kg and energy density (Ed) of 60.834 Wh/kg. A coin cell SC device using an rGO/AC–HDC3D15M electrode with a 3M KOH electrolyte exhibited a high Cs of 65.585 F/g with a high energy density of 5.123 W h/kg and power density of 47.286 W/kg. Thus, the novelty of this manuscript is that (1) the structure of the rGO/AC–HDC–3D15M composite could promote fast ionic and electronic migration during charging and discharging and (2) a rGO/AC–HDC–3D15M composite, which showed electric double-layer capacitor (EDLC) could produce a positive synergistic effect for efficient electrochemical reactions. Moreover, the high surface area of the rGO/AC–HDC–3D15M composite may mitigate the volume expansion of electrodes during cycling. Thus, this work shows that an rGO/AC–HDC–3D15M composite prepared using a hydrothermal process with 3-D ball milling can show enhanced electrochemical performance for the fabrication of an EDLC supercapacitor device.
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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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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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Dielectric and electrochemical properties of hybrid Pt nanoparticles deposited on reduced graphene oxide nanoparticles /poly (vinylidene fluoride) nanocomposites
(2021-06-01)
Karaphun, Attaphol
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Tuichai, Wattana
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Chanlek, Narong
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Sriwong, Chaval
;
Ruttanapun, Chesta
Nano-sized platinum (Pt) materials deposited on reduced Graphene Oxide (rGO) nanosheets (hybrid Pt-rGO nanoparticle) were prepared by the seed-mediated growing process using 20 wt% of Pt nanomaterials in rGO suspension. Dielectric properties of hybrid Pt-rGO nanoparticles/poly (vinylidene fluoride) nanocomposites (Pt-rGO/PVDF nanocomposites) were synthesized by a liquid–phase assisted dispersion and hot–pressing methods with different volume fractions (f) of hybrid Pt-rGO nanoparticle loading PVDF nanocomposites. The observed particle size of Pt nanomaterials deposits on rGO nanosheets was 5 nm. The dielectric constant (ε′) of Pt-rGO/PVDF nanocomposites was increased with increasing hybrid Pt-rGO nanoparticle. The volume fraction f<inf>Pt-rGO</inf> ≈0.0786 exhibited excellent ε′ ≈ 86 with very low loss tangent (tanδ) ≈ 0.021 at 1 kHz. High dielectric properties of Pt-rGO/PVDF composite should be ascribed to combination of the micro-capacitor and Maxwell–Wagner–Sillars (MWS) effects. Electrochemical properties of speciﬁc capacitances (C<inf>sc</inf>) and capacity retention of hybrid Pt-rGO nanoparticle electrode were investigated by the cyclic voltammetry and the galvanostatic charge-discharge. Interestingly, the hybrid Pt-rGO nanoparticle electrode displayed maximum C<inf>sc</inf> value of 169.8 F g−1 at the current densities of 0.25 A g−1. This was due to the occurrence of various oxygen functional groups in the rGO- and Pt+ ions as contributing to form of pseudo-capacitance in hybrid Pt-rGO nanoparticle.

Sriwong, Chaval

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