Wongwiriyapan, Winadda

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Alternative Name

Wongwiriyapan, W.

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Integrated Innovative Technology

winadda.wo@kmitl.ac.th

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Control of Manganese Oxide Hybrid Structure through Electrodeposition and SILAR Techniques for Supercapacitor Electrode Applications
(2023-08-01)
Klangvijit, Kanisorn
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Wongwiriyapan, Winadda
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Uwanno, Teerayut
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Obata, Michiko
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Fujishige, Masatsugu
Manganese oxide has been studied as a promising supercapacitor electrode due to its high theoretical capacitance, low cost, and environmental friendliness. Supercapacitor performance such as specific capacitance, resistance, and cycle life greatly depends on the morphology and crystal structure of manganese oxide. In this study, a Mn<inf>3</inf>O<inf>4</inf> hybrid structure was successfully synthesized using electrodeposition and successive ionic layer adsorption and reaction (SILAR) techniques which are simple, cost-effective, and low-temperature wet chemical processes. It was found that Mn<inf>3</inf>O<inf>4</inf> morphology is different depending on manganese precursors and synthesis techniques. Sea-grape-like and bird nest-like morphologies were obtained via the electrodeposition technique, while flower-like and nanoparticle morphologies were formed via the SILAR technique using manganese acetate and manganese sulfate as precursors, respectively. The hybrid structure of the nanoparticle-decorated bird nest-like heterostructure was prepared using manganese sulfate electrodeposition and subsequent SILAR deposition of manganese acetate. X-ray photoelectron spectroscopy confirmed the Mn<inf>3</inf>O<inf>4</inf> formation. Electrochemical properties of manganese oxide hybrid structure were systematically studied with cyclic voltammetry and galvanostatic charge–discharge, showing the highest areal capacitance of 390 mF cm−2 at 0.1 mA cm−2 with series and charge transfer resistances down to 4.55 and 4.91 Ω in 1 M sodium sulfate electrolyte.
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Graphene nanosheet-grafted double-walled carbon nanotube hybrid nanostructures by two-step chemical vapor deposition and their application for ethanol detection
(2019-12-01)
Muangrat, Worawut
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Wongwiriyapan, Winadda
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Morimoto, Shingo
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Hashimoto, Yoshio
Here, we present a facile technique for synthesis of graphene nanosheet (GNS)-grafted double-walled carbon nanotube (DWCNT) hybrid carbon nanostructures (here after referred to as G-DWCNTs) by directly growing GNSs along the sidewalls of DWCNTs using a two-step chemical vapor deposition (CVD). DWCNTs were synthesized by floating catalyst CVD at 1300 °C using ferrocene and thiophene dissolved in ethanol. Then, GNSs were grafted onto the synthesized DWCNT bundles by thermal CVD at 1300 °C using ethanol. The sharp-edged petal-like structure of GNSs were grown along the sidewalls of DWCNT bundles while maintaining the one-dimensional structure of DWCNT. Next, DWCNTs and G-DWCNTs were dispersed in ethanol, then deposited on the paper using vacuum filtration method and used for ethanol detection. G-DWCNTs sensor exhibited a 3-fold improvement in the response to ethanol vapor compared to the DWCNTs sensor. The sensing mechanism of DWCNTs and G-DWCNTs can be described in terms of charge transfer between the gas molecules and sensing material. These results demonstrate that the facile technique by two-step CVD method provides a promising approach for simple and low-cost technique to synthesize the hybrid nanostructure of GNSs and DWCNTs. The new hybrid carbon nanostructures are attractive for gas sensing application.
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Nondestructive Localization of Subvisual Defects in Laser-Induced Graphene via Machine-Learning-Assisted Electrical Resistance Tomography
(2026-06-16)
Minakawa, Keiya
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Takanashi, Kotaro
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Kimura, Yuki
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Klamchuen, Annop
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Wongwiriyapan, Winadda
Although conventional imaging techniques excel at capturing structural changes, they frequently overlook functional degradations that lack morphological signatures. Here, we demonstrate machine-learning-assisted electrical resistance tomography (ML-ERT) as a robust modality for the rapid, nondestructive localization of “subvisual” defects in porous laser-induced graphene (LIG). By employing masked O<inf>2</inf> plasma irradiation, we introduced localized defects that exhibit a dramatic resistance surge up to 4 orders of magnitude while remaining indistinguishable under visual and electron microscopy. Our ML-ERT framework, powered by a one-dimensional convolutional neural network inverse solver, successfully pinpointed these hidden failures once the resistance contrast reached a threshold of R/R<inf>0</inf> ≥ 6.71. Furthermore, 3D finite element analysis revealed that the tomographic contrast is driven by an effective conductive volume loss exceeding 30%, identifying the degradation of internal conductive pathways as the primary mechanism. These results establish ML-ERT as a high-sensitivity diagnostic tool capable of visualizing electrically critical but optically invisible failures, providing a definitive solution for the quality control of large-area carbon electronics.
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Hemp-Derived Hierarchical Porous Carbon with an Optimized Pore Structure by NaOH Activation for Supercapacitor Applications
(2025-11-11)
Bowornthommatadsana, Khemjiranee
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Klangvijit, Kanisorn
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Uwanno, Teerayut
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Phonyiem Reilly, Mayuree
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Yordsri, Visittapong
This study focuses on converting hemp hurd, a byproduct of hemp stalk processing, into high-performance activated carbon for supercapacitor applications. Hemp hurd was pyrolyzed and subsequently activated with NaOH at various ratios (biochar:NaOH = 1:1, 1:2, 1:3, 1:4). The Hurd-4 condition (1:4 ratio) yielded the highest specific surface area, 3033 m2/g. Our findings indicate that increasing the chemical activation ratio enhances the mesopore-to-micropore volume ratio (V<inf>meso</inf>/V<inf>micro</inf>) to 1.58 while maintaining a sufficient micropore volume for ion storage. This balanced pore structure effectively increased the specific capacitance, achieving a maximum of 725 F/g at a current density of 0.3 A/g in a 1 M H<inf>2</inf>SO<inf>4</inf>electrolyte. When assembled into a coin cell with an organic electrolyte, Hurd-4 exhibited a maximum specific capacitance of 39 F/g, a maximum energy density of 34 Wh/kg, and a power density of 395 W/kg, surpassing commercial activated carbon. Additionally, the device maintained 78% capacitance retention after 10,000 cycles at a current density of 0.5 A/g. The superior electrochemical properties are attributed to the largest specific surface area, highest pore volume, and optimal mesopore volume ratio. These results demonstrate the potential of hemp hurd as a highly efficient precursor for synthesizing activated carbon for high-performance supercapacitors.
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Preparation of activated carbon from bamboo-cellulose fiber and its use for EDLC electrode material
(2017-04-01)
Fujishige, Masatsugu
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Yoshida, Ichiro
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Toya, Yumiko
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Banba, Yasuo
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Oshida, Kyo ichi
Carbonization and post activation of bamboo-cellulose fiber was carried out. The carbonization was performed at 600°C, 800°C and 1000°C in argon atmosphere. Then, they were activated by heating solid mixture of carbonized bamboo and sodium hydroxide (NaOH) at 720°C in argon atmosphere. The largest specific surface area of the resulting activated carbon (carbonized at 600°C) was 2366m2/g with the micropore volume of 0.71cm3/g and mesopore volume of 0.06cm3/g. It was found that the carbonization temperature is very important to obtain nanoporous carbon with large specific surface area. The distributions of interlayer spacing were estimated from the power spectra of the TEM images of the carbonized samples. It showed the interlayer spacing of basic structural unit (BSU) decreased from 0.49nm (BC-0600) through 0.47nm (BC-0800) to 0.45nm (BC-1000). The activated carbon was used as the host material of the electrodes of coin type electric double-layer capacitor (EDLC) with organic electrolyte. The observed specific capacitance was 43F/g (23F/cm3) for the activated carbon (carbonized at 600°C), comparable to 44F/g (22F/cm3) of commercial activated carbon (MSP). The corresponding values for the activated carbons (carbonized at 800°C and 1000°C) were 40F/g (23F/cm3) and 17F/g (12F/cm3), respectively.
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Optimizing Electrochemical Performance: A Study of Aqueous Electrolytes with Hemp-Derived Activated Carbon for Supercapacitors
(2025-02-25)
Klangvijit, Kanisorn
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Bowornthommatadsana, Khemjiranee
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Phonyiem Reilly, Mayuree
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Uwanno, Teerayut
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Yordsri, Visittapong
This work investigates the synthesis and electrochemical performance of hemp-derived activated carbon (HAC) for supercapacitor electrode applications. HAC was prepared through NaOH chemical activation, and its electrochemical characteristics were evaluated using three different electrolytes: acidic (H<inf>2</inf>SO<inf>4</inf>), neutral (Na<inf>2</inf>SO<inf>4</inf>), and basic (KOH). The specific surface area of HAC was found to be exceptionally high, measuring 2612 m2/g, surpassing that of commercially available activated carbon (AC). Surface analysis revealed the presence of an oxygen functional group, which provided additional pseudocapacitive active sites. When 1 M H<inf>2</inf>SO<inf>4</inf> was employed as the electrolyte, HAC demonstrated a maximum specific capacitance of 594 F/g (302.4 F/cm3) at a current density of 0.3 A/g. Notably, the HAC electrode exhibited significantly higher energy density and power density, reaching values of 82 Wh/kg (135.7 mWh/cm3) and 188 W/kg (311 mW/cm3), respectively, when compared to commercial AC. These results highlight the potential of HAC as a cost-effective and high-performance electrode material, particularly when paired with H<inf>2</inf>SO<inf>4</inf> as the electrolyte due to their ideal micropore/mesopore ratio for H<inf>2</inf>SO<inf>4</inf> electrolyte access.
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Effect of Carbonization Temperature on Physical Properties and Specific Capacitance of Activated Carbon Derived from Banana Stem and Its Application as Supercapacitor Electrodes
(2023-01-01)
Dulyaseree, Paweena
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Sama, Hasanee
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Sada, Suraida
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Ukkakimapan, Pundita
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Yordsri, Visittapong
In this work, activated carbons (ACs) for electrodes supercapacitor applications were successfully synthesized from banana stem. Banana is one of the popular fruits that is easy to grow and most parts of the plant can be used. However, banana cultivation generates a lot of wastes, especially from the stem. Thus, using banana stem as raw material for ACs was investigated. The synthesis of AC consisted of 2 processes; carbonization and activation. The advantage of a two-step synthesis was the low weight loss of charcoal. Firstly, the carbonization process was conducted by varying the temperature between 300-600°C, and then inorganic elements were removed by treatment with 1 M sulfuric acid. After that, activation was conducted at 720°C under an argon atmosphere. The electrochemical properties of banana stem-derived ACs (BCH-ACs) were studied using sodium sulfate as an electrolyte. The BCH-ACs carbonized at 400°C showed the highest performance with a specific capacitance of 55.45 Fg-1, an energy density of 7.70 Whkg-1 and a power density of 133.94 Wkg-1. The highest specific capacitance of the BCH400-AC was likely due to the increase in the amount of oxygenated functional group, which facilitated the access of electrolyte ions into the electrode. These results suggest that banana stem can be used to synthesize ACs via carbonization at 400°C, and the ACs generated can be applied as electrode in supercapacitors.
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Comparison of acid exfoliators in carbon nanosheets synthesis from stinging nettle (Urtica dioica) for electrochemical applications
(2020-12-01)
Nuilek, Kanokon
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Wongwiriyapan, Winadda
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Sattayarut, Vichuda
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Simon, Andrea
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Koncz-Horváth, Daniel
Carbon nanosheets (CNs) were successfully synthesized from nettle stem (NS) which is an inexpensive material with a high carbon content that is abundantly available in nature. CNs were produced using chemical (potassium hydroxide activation and acid exfoliation) and thermal treatments. Sulfuric (H<inf>2</inf>SO<inf>4</inf>), phosphoric (H<inf>3</inf>PO<inf>4</inf>) and nitric (HNO<inf>3</inf>) acid solutions were used for exfoliation. CNs exfoliated by H<inf>3</inf>PO<inf>4</inf> have higher specific surface area (789 m2 g−1) compared to CNs exfoliated by H<inf>2</inf>SO<inf>4</inf> (705 m2 g−1) and HNO<inf>3</inf> (106 m2 g−1). In this work, NSCNs were found to be a potential candidate for electrode material in electrochemical capacitors. The maximum specific capacitance of the NSCNs exfoliated by H<inf>3</inf>PO<inf>4</inf> is found to be 27.3 F g−1 at a current density of 0.05 A g−1, while the specific capacitance of NSCNs exfoliated by H<inf>2</inf>SO<inf>4</inf> and HNO<inf>3</inf> is 9.34 F g−1 and 1.71 F g−1, respectively. Energy density (0.06–0.95 Wh kg−1) and power density (20.9–26.7 W kg−1) of NSCNs are confirmed to be supercapacitor materials and can be applied in energy storage devices.
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Band gap and photo charge carrier tailoring in zirconium doped carbon nitride using ZrCl4-DMF-melamine for photocatalytic degradation of rhodamine B
(2025-03-05)
Pinming, Chinathun
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Yang, Qingshan
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Kayunkid, Navaphun
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Yordsri, Visittapong
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Wongwiriyapan, Winadda
Improving the performance of carbon nitride (CN) photocatalysts in photocatalytic degradation applications involves optimizing their morphology, electronic properties, and optical characteristics. Zirconium-doped carbon nitride (Zr-doped CN) photocatalysts were synthesized using dimethylformamide (DMF) as a solvent to facilitate the formation of complex molecular structures for effective metal doping. By varying the concentration of the zirconium tetrachloride (ZrCl<inf>4</inf>) precursor between 1 and 3 mmol, we observed significant enhancements in photocatalytic activity. Notably, controlling the ZrCl<inf>4</inf> concentration below 3 mmol prevented the formation of zirconium oxide phases, which could otherwise negatively affect the photocatalytic performance. Zr incorporation led to the morphological transformation of CN from a bulk structure into a hierarchical porous structure, increasing the surface area to 135 m2 g−1. Additionally, Zr doping changed the band energy and electronic properties, creating an optimal energy level for generating oxygen radicals in the photocatalytic water-splitting processes. The photocatalytic degradation of rhodamine B showed that the Zr-doped CN photocatalysts achieved 4.5-fold better performance than undoped CN. Moreover, a small amount of ethylenediaminetetraacetic acid (EDTA) significantly enhanced the photocatalytic efficiency of Zr-doped CN compared to that of undoped CN. These results indicate that combining Zr-doped CN with other materials to create Z-scheme or S-scheme structures could further enhance its performance, thus emphasizing the potential of increasing photocatalytic efficiency by optimizing energy band structures and forming heterostructured photocatalysts.
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Poly(methyl methacrylate) and thiophene-coated single-walled carbon nanotubes for volatile organic compound discrimination
(2016-02-01)
Muangrat, Worawut
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Chodjarusawad, Thanawee
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Maolanon, Rungroj
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Pratontep, Sirapat
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Porntheeraphat, Supanit
Poly(methyl methacrylate) (PMMA) and thiophene-coated single-walled carbon nanotubes (SWNTs) were fabricated for use in volatile organic compound (VOC) detection. Pristine SWNTs were separately coated with PMMA (PMMA/SWNTs) and thiophene (thiophene/SWNTs) by spincoating. Pristine SWNTs showed the highest response to methanol, while PMMA/SWNTs enabled 5.4-fold improved dichloromethane detection and thiophene/SWNTs enabled 1.4-fold improved acetone detection compared with pristine SWNTs. The sensor response of PMMA/SWNTs to dichloromethane and that of thiophene/SWNTs to acetone can be attributed to the Hildebrand solubility parameter (HSP). The more similar the HSP, the higher the sensor response. The sensor response of pristine SWNTs to methanol is related to the diffusion coefficient and molecular size. The relationships between the vapor concentration and sensor response of PMMA/SWNTs to dichloromethane and thiophene/SWNTs to acetone are based on Henry's adsorption isotherm, while that of pristine SWNTs to methanol is based on the Henry-clustering model. Principal component analysis (PCA) results show that dichloromethane, acetone, and methanol were successfully discriminated.

Wongwiriyapan, Winadda

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