Thongkam, Montree

Preferred name

Thongkam, Montree

Main Affiliation

School of Science

montree.th@kmitl.ac.th

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A double-shell capsule catalyst with core-shell-like structure for one-step exactly controlled synthesis of dimethyl ether from CO2 containing syngas
(2011-08-10)
Yang, Guohui
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Thongkam, Montree
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Vitidsant, Tharapong
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Yoneyama, Yoshiharu
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Tan, Yisheng
A zeolite capsule catalyst Cr/ZnO-S-Z was prepared successfully by a novel dual-layer method, in which one layer of neutral Silicalite-1 zeolite shell was first synthesized on the bimetallic Cr/ZnO core catalyst, acting as the intermediate layer for the following H-type H-ZSM-5 zeolite shell direct synthesis on its surface. By using this dual-layer method, it can be easily realized that the formation of H-ZSM-5 zeolite membrane on the millimeter-sized bimetallic substrates. Direct synthesis of dimethyl ether (DME) from syngas at higher reaction temperature was the application of this zeolite capsule catalyst to test its catalytic performance. In reaction, this zeolite capsule catalyst could realize the exactly controlled synthesis of DME, suppressing the formation of other alkane/alkene by-products simultaneously, demonstrating its exclusive ability for the selective synthesis of target product compared with the conventional hybrid catalyst. © 2011 Elsevier B.V. All rights reserved.
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Optical properties of Cu0.95Pt0.05Fe0.97Sn0.03O2 for p-type transparent conducting oxide materials
(2013-08-30)
Ruttanapun, Chesta
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Kahatta, Sagulthai
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Boonchom, Banjong
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Vittayakorn, Naratip
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Thongkam, Montree
The Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> sample has been synthesized by a solid-state reaction to investigate optical properties of materials of transparent conducting oxide. Crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature (300 to 860 K), while the XPS and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient reveals the samples displays the p-type conducting. The XPS spectra show the Sn2+ state stabling in this compound. The optical direct gap is 3.45 eV as a visible-transparent material. These results support that the Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> oxide compounds, of which the Cu1+ and Fe3+ sites are substituted by the Pt1+ and Sn2+ ions respectively, are p-type transparent conducting oxide materials. © (2013) Trans Tech Publications, Switzerland.
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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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Adsorption kinetic of direct dyes from aqueous solution on zeolite lta
(2021-01-01)
Thongkam, Montree
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Trisupakitti, Somsuk
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Palama, Thongsuk
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Senajuk, Watchara
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Nausri, Chompoo
The analysis of adsorption relies on the equilibrium state of the mass. It is the relationship between the concentration of the adsorbate in the liquid phase and the concentration of the adsorbate in the solid phase. The relationship is written as an isotherm of the adsorption graph. Zeolite LTA was used as adsorbent to remove dye from solution in a batch adsorption system. The adsorption isotherm showed that the Langmuir model was better than the Freundlich model. Adsorption of adsorbate consists of a diffusion process through the fluid layer around the adsorbent material and the diffusion in the cavity. This research found that a pseudo-second order model was a better fit to measured adsorption data.
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Electrical and optical properties of p-type CuFe1-xSn xO2 (x = 0.03, 0.05) delafossite-oxide
(2013-01-14)
Ruttanapun, Chesta
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Boonchom, Banjong
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Thongkam, Montree
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Kongtaweelert, Samart
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Thanachayanont, Chanchana
The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> (x = 0.03, 0.05) delafossite samples have been synthesized by a solid-state reaction to investigate electrical and optical properties of the transparent conducting oxide materials. Crystal structure was characterized by XRD. The electrical conductivity and Seebeck coefficient were measured in the high temperature range of 300 to 960 K, while the Hall coefficient, XPS, and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks of the samples indicate the delafossite structure phase, and the XPS spectra reveal the stable Sn 2+-doping state. The Seebeck and Hall coefficient display a positive sign indicating the p-type conducting oxide. The optical allowed direct gap is 3.45 eV as a visible-transparent material. The activation energies for polaron hopping between Sn2+ sites and Fe3+ sites of 36 and 32 meV are obtained from the samples having x = 0.03 and 0.05, respectively. The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> delafossite oxide compounds, of which the Fe3+ sites in the CuFeO<inf>2</inf> are substituted by the Sn2+ ions, are p-type transparent conducting oxide materials. The activation energy is found to decrease with an increased in Sn content. © 2013 American Institute of Physics.
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Effects of Zinc and Aluminum on the CuO Crystalline Size for Direct Dimethyl Ether Synthesis from Syngas
(2021-09-01)
Thongkam, Montree
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Piyabunditgul, Nanchapak
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Trisupakitti, Somsuk
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Rungrojchaipon, Pesak
The effects of zinc and aluminum on the CuO crystalline size for direct dimethyl ether (DME) synthesis from syngas were investigated. Metal oxide catalysts were synthesized with various molar ratios of CuO by the precipitation method, and by the co-precipitation method with CuO/ZnO (CZ), CuO/ZnO/Al<inf>2</inf>O<inf>3</inf> (CZA), and CZA at ratios of 1:1, 2:2:1, and 6:3:1, respectively. The acid catalysts (γ-Al<inf>2</inf>O<inf>3</inf>, HZSM-5) were added to the metal oxide catalysts by physical mixing. The catalysts were characterized morphologically and their acidities were determined. Loading of zinc and aluminum at different ratios showed that CZA (2:2:1) gave the smallest CuO crystalline size, appropriate for the methanol synthesis reaction. γ-Al<inf>2</inf>O<inf>3</inf> has a weak to moderate acidity range, suitable for DME synthesis. Moreover, the bifunctional catalyst, CZA (2:2:1)/γ-Al<inf>2</inf>O<inf>3</inf>, had the highest surface area as well as the highest %CO conversion and %DME selectivity.
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A simple route to synthesize ferromagnetic binary calcium iron pyrophosphate CaFeP2O2 using aqueous-acetone media
(2013-08-30)
Chaiyasith, Pachernchaipat
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Ruttanapun, Chesta
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Thongkam, Montree
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Kongteweelert, Samart
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Woramongkonchai, Somsak
A binary calcium iron pyrophosphate CaFeP<inf>2</inf>O<inf>7</inf> was synthesized by solid state route using the mixing of calcium carbonate, iron metal and phosphoric acid in aqueous-acetone media at 600°C. The XRD datum indicates the formation of CaFeP<inf>2</inf>O<inf>7</inf> phase without the presence of any phase impurities. FTIR result indicates the presence of the P<inf>2</inf>O<inf>7</inf> 4- anion in the structure. Sheet-like microparticle of CaFeP<inf>2</inf>O<inf>7</inf> was revealed by SEM. Room temperature magnetization result showed ferromagnetic behavior of the synthesized CaFeP<inf>2</inf>O<inf>7</inf>, with saturation-specific magnetization value of 11.067 emu g-1 at 10kOe. The magnetic feature of the synthesized CaFeP<inf>2</inf>O<inf>7</inf> in this work compared with M<inf>2</inf>P<inf>2</inf>O<inf>7</inf> (M = Ca and Fe), its isotypic (CaMP2O7 (M= Mn and Co) and CFeP<inf>2</inf>O<inf>7</inf> (C= Co and Cu) reported in our previous works is important properties for specific applications. © (2013) Trans Tech Publications, Switzerland.
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Facile, alternative synthesis of spherical-like ca(H2PO4)2•H2O nanoparticle by aqueous-methanol media
(2013-08-30)
Kongteweelert, Samart
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Ruttanapun, Chesta
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Thongkam, Montree
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Chaiyasith, Pachernchaipat
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Woramongkonchai, Somsak
Spherical-like calcium dihydrogenphosphate monohydrate (Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>•H<inf>2</inf>O) nanostructure was successfully prepared by the mixing of calcium carbonate and phosphoric in aqueous-methanol media at ambient temperature for 30 min. Three thermal decomposition step and higher stability at over 800°C of the prepared sample are different from the earlier works. Spherical-like Ca(H<inf>2</inf>PO<inf>4</inf>)<inf>2</inf>•H<inf>2</inf>O nanostructure with diameter < 100 nm confirmed by SEM may be important for potential applications. This method of synthesis by aqueous-methanol media is a fast and simple method and it is expected to be applicable for the synthesis of other nanocrystalline calcium phosphates. © (2013) Trans Tech Publications, Switzerland.
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A new synthesis of BaHPO4 precipitated by BaCO3-H4PO4-NaOH system at room temperature
(2013-08-30)
Boonchom, Banjong
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Ruttanapun, Chesta
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Thongkam, Montree
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Chaiyasith, Pachernchaipat
;
Woramongkonchai, Somsak
Barium hydrogenphosphate, BaHPO<inf>4</inf> was synthesized for the first time through simple and rapid method using BaCO<inf>3</inf>-H<inf>3</inf>PO<inf>4</inf>-NaOH, pH =9.0 at room temperature for 30 min. The studied BaHPO<inf>4</inf> decomposed in a single well-defined stage via deprotonated hydrogenphosphate reactions, revealed by TG/DTG and DSC techniques. The calculated wavenumbers based on DSC peak were comparable with FTIR results, which support the breaking bonds of P-OH (HPO<inf>4</inf>2-) in the deprotonated hydrogenphosphate reactions. The thermodynamic functions (ΔH*, ΔG*, and ΔS*) for the deprotonated hydrogenphosphate reactions calculated from DSC data indicate that the deprotonated HPO<inf>4</inf>2- reaction occur a lower-energy pathway and spontaneous process. The FTIR, XRD and SEM data of the studied BaHPO<inf>4</inf> and its decomposed product Ba<inf>4</inf>P<inf>2</inf>O<inf>7</inf> are also reported. © (2013) Trans Tech Publications, Switzerland.
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A Well-Defined Core–Shell-Structured Capsule Catalyst for Direct Conversion of CO2 into Liquefied Petroleum Gas
(2020-04-21)
Li, Hangjie
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Zhang, Peipei
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Guo, Lisheng
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He, Yingluo
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Zeng, Yan
A Pd/SiO<inf>2</inf>@S1@H-ZSM-5 capsule catalyst (Pd/SiO<inf>2</inf>–SZ) is fabricated through a dual-layer crystal growth method with an auxiliary hydrothermal reaction. The catalyst exhibits excellent selectivity to liquefied petroleum gas (LPG) in CO<inf>2</inf> hydrogenation reactions, which is attributed to the tandem reactions of methanol synthesis on the Pd/SiO<inf>2</inf> core catalyst and methanol dehydration to hydrocarbons on the H-ZSM-5 shell. The Pd/SiO<inf>2</inf>–SZ capsule catalyst has a similar mesoporous structure, narrow range of Pd particles size distribution, and consistent reduction characteristics to the Pd/SiO<inf>2</inf> core catalyst. It maintains the physical and chemical properties of the core catalyst throughout the H-ZSM-5 shell synthesis process. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy results reveal that the H-ZSM-5 zeolite shell completely encapsulates the Pd/SiO<inf>2</inf> core catalyst. Compared with the crushed capsule catalyst (Pd/SiO<inf>2</inf>–SZP), the well-defined-structured Pd/SiO<inf>2</inf>–SZ catalyst has a much higher LPG selectivity of 33.6 %, owing to the well-matched reactions at the Pd/SiO<inf>2</inf> core and H-ZSM-5 shell.

Thongkam, Montree

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