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Nanoarchitectonics of carbon-based electrodes via activated carbon/carbon composite xerogels by CO2
(2025-09-01)
Sirichan, Kasawan
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Kraiwattanawong, Kriangsak
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Bumroongsakulsawat, Palang
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Assabumrungrat, Suttichai
Carbon/carbon (C/C) composites, characterized by trimodal porous structures and highly tunable surfaces, offer promising prospects for electrochemical applications within the framework of nanoarchitectonics. However, recent research lacks systematic investigations into property-controlled performance. This study explores the effects of functional groups, surface area, and pore architecture in CO<inf>2</inf>-activated C/C composite xerogels synthesized from resorcinol-formaldehyde (RF) sol and cotton fibers (CFs). Increased activation time and CF content enhanced porosity, functional group density (O[sbnd]H and C[dbnd]O), and structural disorder. The macropores introduced by CFs facilitated deeper CO<inf>2</inf> penetration, thereby increasing meso‑ and microporosity, surface area, and specific capacitance. Electrochemical performance measured through cyclic voltammetry and charge/discharge analysis revealed that capacitance was governed primarily by surface area rather than pore geometry. Specific capacitance and surface area increased from 144 to 344 F g⁻¹ and from 575 to 1471 m² g⁻¹, respectively, under 0.5 A g⁻¹ discharge.
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Porosity development of templated porous carbons dried by vacuum as carbon electrodes for electric double-layer capacitors
(2023-03-15)
Kraiwattanawong, Kriangsak
Resorcinol and formaldehyde (RF) resin serves as the carbon precursor for porous carbons and carbon/carbon composites possessing a high specific surface area (SSA). This work presents the porosity improvement by the elimination of cotton fibers (CF) from CF/RF composite hydrogels subsequently exchanged by tertiary butyl alcohol (TBA), dried by vacuum, and carbonized. This route contributes the templated porous carbons (TPC) with an asymmetric structure comprising micropores, mesopores, and macropores. At 0.25 of the CF/RF weight ratio, TPC dried by vacuum apparatus has SSA of 2,102 m2 g−1, whereas TPC dried by evaporation only offers SSA of 663 m2 g−1. Using the vacuum acts as pseudo-freeze drying during TBA removal, forming sponge-like carbon and allowing ultra-high SSA. The electrochemical properties of vacuumed TPCs were analyzed, showing that TPC at 0.25 of the CF/RF weight ratio possessed 626 F g−1 more than TPC at 0.00 of the CF/RF weight ratio which had 392 F g−1 at 200 mA g−1.
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Effect of cotton fiber addition and carbonization temperature to the structural-and-surface-property change of C/C composite xerogels as electrodes for electric double layer capacitors
(2022-11-01)
Sirichan, Kasawan
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Kraiwattanawong, Kriangsak
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Bumroongsakulsawat, Palang
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Assabumrungrat, Suttichai
Carbon/carbon (C/C) composites containing micropores, mesopores and macropores as trimodal structure are a class of promising electrode materials for electric double layer capacitors. The existence of cotton fibers can change pore structure, electrical resistance and surface properties of C/C composites by the increase of carbonization temperature. In this work, C/C composite xerogel electrodes possessing trimodal structure were prepared from resorcinol, formaldehyde, and cotton fibers. Sufficiently high carbonization temperatures had to be reached to obtain electrodes possessing high electrical double layer capacitance. The addition of cotton fibers lowered effective carbonization temperatures and created macropores, which facilitated transport of carbonization gases and heat transfer in pores located deep in the samples. Cotton fibers also prevented collapse of mesopores during vacuum drying. Samples with cotton fibers added had 27–40% more mesopore volume. The highest specific capacitance obtained was 175 F g−1 during discharge at 0.5 A g−1.
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Effects of Nanocrystal Cellulose from Bamboo on the Flexural Strength of Acrylic Resin: In Vitro
(2022-07-01)
Aupaphong, Visakha
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Kraiwattanawong, Kriangsak
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Thanathornwong, Bhornsawan
The purpose of this study is to evaluate the effects of nanocrystal cellulose (NCC) from bamboo on the flexural strength of heat-cured acrylic resin. A total of 35 specimens (3.3 mm × 10 mm × 64 mm) were prepared and the specimens were divided into five groups of seven specimens each. Group 1 used conventional acrylic resin that was prepared based on the instructions of the manufacturer (0%). The filled NCC from bamboo fiber in four concentrations (0.25, 0.5, 1, and 2% w/w) was used in the four-reinforcing resin workpiece groups. The specimens were loaded until failure occurred on a three-point bending test machine. One-way analysis of variance and Dunnett’s multiple comparison test at a 95% confidence level were used to determine the statistical differences in the flexural strength among the five groups. The results found that the average flexural strength of five specimen groups (0, 0.25, 0.5, 1, and 2% w/w) were 60.11 ± 2.4, 60.75 ± 2.18, 66.50 ± 5.08, 56.04 ± 0.31, and 48.05 ± 2.61 MPa, respectively. The flexural strength of 0.5 mg% w/w NCC-reinforced acrylic resin was significantly higher than the control group (p < 0.01). The reinforced NCC from bamboo fiber to acrylic resin improved the flexural strength properties.
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A review on the development of a porous carbon-based as modeling materials for electric double layer capacitors
(2022-02-01)
Kraiwattanawong, Kriangsak
Carbon electrodes are a key factor for electric double layer capacitors (EDLCs). Carbon gels have high porosity with a controllable pore structure by changing synthesis conditions and modifying preparation processing to improve the electrochemical performance of EDLCs. This review summarizes the preparation of carbon gels and their derivatives, the criteria to synthesize high surface area in each process, the development by some carbon forms, and EDLC applications. Porous carbons are also prepared as model materials by concentrating on how pore structure increases electrochemical capacitance, such as electronic and ion resistance, the tortuosity of pore channel, suitable micropore and mesopore sizes, and mesopore size distribution. This review emphasizes the significance of pore structures as the key factor to allow for the design of suitable pore structures that are suitable as the carbon electrode for EDLCs.
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Influence of evaporation drying on the porous properties of carbon/carbon composite xerogels
(2021-08-02)
Kraiwattanawong, Kriangsak
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Sano, Noriaki
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Tamon, Hajime
Carbon/carbon (C/C) composite xerogels dried by evaporation were prepared in this study to observe the change of their porous properties and their morphology by nitrogen sorption apparatus and a scanning electron microscope. Resorcinol and formaldehyde (RF) sols as a matrix phase and cotton fibers (CF) as a dispersed phase were mixed and gelated to be CF/RF composite hydrogels. The composite hydrogels were exchanged by t-butanol (TBA), dried by evaporation at 50◦C, and carbonized at 1000◦C to become the C/C composite xerogels. The results show that the CF addition does not decrease the mesoporous properties of the C/C composite xerogels. Moreover, the CF addition can alleviate the pore shrinkage, and it can maintain the mesopore structure. The mesopore size and the micropore size of C/C composites are insignificantly changed because the CF addition and the solvent exchange using TBA may suppress the pore shrinkage despite the gas-liquid interface existing during the evaporation drying.
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Corrigendum to “Macropore-assisted electrolyte transfer inside binder-free templated carbon xerogels as carbon electrode for electric double layer capacitors” [Eur. Polym. J. 130 (2020) 109678] (European Polymer Journal (2020) 130, (S0014305720303153), (10.1016/j.eurpolymj.2020.109678))
(2020-08-05)
Kraiwattanawong, Kriangsak
I am very sorry because I had checked my article and its SI document again. I found a mistake about the y-axis in Fig. 10(b) and Fig. S4–S6. The correct y-axis is “Voltage (V)”, but I made the mistake in the article “Capacitance (F/g)”. The author would like to apologise for any inconvenience caused.
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Macropore-assisted electrolyte transfer inside binder-free templated carbon xerogels as carbon electrode for electric double layer capacitors
(2020-05-05)
Kraiwattanawong, Kriangsak
Capacitive performance of electric double layer capacitors is influenced by specific surface area, while pore structure also promotes electrolyte transfer inside a carbon electrode. Organic electrolytes require macropores, whereas aqueous electrolytes operate best using mesopores for electrolyte transfer. Templated carbon xerogels (TCXs) were prepared from resorcinol and formaldehyde with cotton fibers as a hard template containing macropores, mesopores and micropores as the carbon electrode. Results suggested that macropores (>50 nm) were contiguously created and connected with mesopore diameters (2–50 nm), leading to convenient ion transport inside the TCXs. Vacuum drying formed sponge-like carbon xerogels that permitted electrolyte transfer. Despite the insignificant change of porous properties, TCXs possessing sponge-like carbon xerogels showed increased capacitance values from 137 F/g to 317 F/g at 200 mA/g in a three-electrode system as a result of macropore-assisted electrolyte transfer in aqueous electrolytes.
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Improvement of the textural properties of templated carbon xerogels using cotton fibres as a hard template dehydrated by sulphuric acid
(2019-02-01)
Kraiwattanawong, Kriangsak
Carbon xerogels have generally low textural properties compared with carbon aerogels and carbon cryogels since the gas-liquid interface produces a capillary force in small pores. In this work, the templated carbon xerogels (TCXs), using resorcinol-formaldehyde (RF) and cotton fibres (CFs) as a hard template, were synthesized by CF removal from CF/RF composite hydrogels by sulphuric acid treatment. The TCX precursors were exchanged by t-butanol, dried by evaporation drying, and carbonized at high temperature. Scanning electron microscope images and Hg intrusion data confirm that TCXs possess macropores whose walls are the carbon xerogel scaffold. Their nitrogen adsorption and desorption isotherms also support that TCXs have micropores and mesopores. The quantities of micropores, mesopores and macropores are improved with the increase of CF utilization. X-ray diffraction allows us to know that TCXs have a graphitic structure. The intensity of D to G from the Raman spectra is also investigated.
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Removal of heavy polynuclear aromatics by activated carbons
(2018-01-01)
Pilawan, Wijai
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Sirikarn, Wisanu
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Kraiwattanawong, Kriangsak
Heavy polynuclear aromatics (HPNA) is a complex molecules generated during hydrocracking process in waxy oil. HPNA is eliminated by a commercial activated carbon in the absorber to prevent the fouling in the pipelines and the decrease of product yield. In this work, the commercial activated carbons containing the different micropores and the different mesopores were selected to investigate the influence of pore structure on the HPNA removal. Here, the surface area of commercial activated carbons were quite equivalent. The results show that the activated carbon possessing the high mesopores can adsorb HPNA better than the activated carbon having the high micropores in spite of the summation of a micropore volume and a mesopore volume are quite equal. Therefore, the mesopore structure is a major role in the HPNA removal.

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