Sooknoi, Tawan

Preferred name

Sooknoi, Tawan

Alternative Name

Sooknoi, T.

Main Affiliation

School of Science

tawan.so@kmitl.ac.th

Now showing 1 - 10 of 25

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Highly Dispersed WOx/SiO2Catalysts Derived from W-TRIS Complex for Efficient Biobutadiene Production from Acetylene-Ethylene Cross-Metathesis
(2025-01-01)
Promchana, Pratya
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Choojun, Kittisak
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Wengwirat, Kanokwan
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Limphirat, Wanwisa
;
Sooknoi, Tawan
Renewable 1,3-butadiene was selectively produced via acetylene-ethylene cross-metathesis over highly dispersed WO<inf>x</inf>/SiO<inf>2</inf>catalysts prepared by a simple impregnation method using the molecular precursor (NH<inf>4</inf>)<inf>2</inf>[W<inf>2</inf>O<inf>6</inf>(TRIS)<inf>2</inf>] (W-TRIS). Compared to catalysts derived from ammonium metatungstate (AMT), the TRIS-derived catalysts exhibited superior WO<inf>x</inf>dispersion and catalytic activity, attributed to stronger W–O–Si interactions as evidenced by XRD, DRUV–vis, Raman spectroscopy, and W L<inf>3</inf>-edge XANES/EXAFS. Systematic variation of WO<inf>3</inf>loading revealed that 5 wt % WO<inf>x</inf>/SiO<inf>2</inf>-TRIS offered the optimal balance of activity and selectivity, achieving 60% acetylene conversion, ∼74% selectivity to 1,3-butadiene, and a turnover frequency (TOF) of 23 h–1. Contact time analysis confirmed that 1,3-butadiene was the primary product, while minor byproducts such as cyclohexene and benzene originated from Diels–Alder cycloaddition followed by dehydrogenation. Reaction temperature screening identified 450 °C as the optimal operating condition; higher temperatures led to increased side reactions. Importantly, long-term testing over 100 h under continuous-flow conditions demonstrated high stability with sustained selectivity and negligible coke formation. These findings underscore the practical advantages of the W-TRIS molecular precursor strategy in designing durable WO<inf>x</inf>/SiO<inf>2</inf>catalysts for efficient and sustainable C<inf>4</inf>chemical production from bioethylene.
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Facile synthesis of the atomically dispersed hydrotalcite oxide supported copper catalysts for the selective hydrogenation of 5–hydroxymethylfurfural into 2,5-bis(hydroxymethyl)furan
(2023-07-15)
Kumar, Raju
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Lee, Hsin Hui
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Chen, En
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Du, Yuan Peng
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Lin, Chan Yi
The selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) using the atomically dispersed supported copper catalyst is investigated. The hydrotalcite oxide supported copper materials (Cu<inf>(x)</inf>HTO) are facilely prepared by coprecipitating metal precursors in a methanolic solution under a tuned pH. The surface characterization involving PXRD, TEM, H<inf>2</inf>/N<inf>2</inf>O-TPR, and XAS reveals unequivocal evidence for the presence of the atomically dispersed copper on HTO surface. XAS specifically indicates the formation of mononuclear copper species, and H<inf>2</inf>/N<inf>2</inf>O-TPR strongly supports the copper atoms of Cu<inf>(5)</inf>HTO are evenly distributed in 99% dispersion. Moreover, the reduced Cu<inf>(5)</inf>HTO (r-Cu<inf>(5)</inf>HTO) enables to completely hydrogenate HMF to BHMF under mild conditions, in comparison to the poor reactivity catalyzed by the hydrotalcite oxide supported copper nanoparticles (r-Cu<inf>(4)</inf>@HTO). The dramatic enhancement of HMF hydrogenation catalyzed by r-Cu<inf>(5)</inf>HTO can be attributed to the fine distribution of copper atoms which are situated homogeneously over HTO surface as well as chemically reactive for the carbonyl group.
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Tailoring the First Coordination Shell of Isolated Ti(IV) Active Sites in Zeolite Frameworks Boosting Catalytic Activity in Epoxidation
(2025-05-08)
Klinyod, Sorasak
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Yomthong, Krissanapat
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Suttipat, Duangkamon
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Pornsetmetakul, Peerapol
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Kidkhunthod, Pinit
We present a strategy to precisely tune the local structure of the tetrahedrally coordinated titanium (Ti) sites incorporated in the zeolite framework via a one-pot hydrothermal synthesis with the aid of NH<inf>4</inf>F without any further postmodification step. This approach effectively prevents typical issues observed in postsynthetic methods, such as Ti leaching and zeolite framework degradation. By optimizing the NH<inf>4</inf>F concentration in the synthesis precursor, the formation of open Ti(OSi)<inf>3</inf>OH and Ti(OSi)<inf>3</inf>F active species can be precisely controlled. To elucidate the relationship between various Ti active species, including closed Ti(OSi)<inf>4</inf>, open Ti(OSi)<inf>3</inf>OH, and open Ti(OSi)<inf>3</inf>F sites and their catalytic performances in methyl oleate (MO) epoxidation, we employed ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), fluorine X-ray absorption near edge structure spectroscopy (F-XANES), and density functional theory (DFT) calculations. Our findings reveal that increased positive charges on Ti active centers, in the order of closed Ti(OSi)<inf>4</inf> < open Ti(OSi)<inf>3</inf>OH < open Ti(OSi)<inf>3</inf>F, correlate with enhanced catalytic performance in MO epoxidation. However, an excessive proportion of Ti(OSi)<inf>3</inf>F species in the framework can diminish catalytic performance by promoting undesired side reactions. Therefore, we propose an optimized balance between open Ti(OSi)<inf>3</inf>OH and open Ti(OSi)<inf>3</inf>F species in the zeolite structure to maximize the catalytic activity of epoxidation.
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Bio-derived butadiene from cross-metathesis over silanol rich WO3 catalysts obtained from copper phyllosilicate
(2025-03-20)
Wengwirat, Kanokwan
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Choojun, Kittisak
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Promchana, Pratya
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Limphirat, Wanwisa
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Sooknoi, Tawan
Bio-butadiene can be produced from cross-metathesis of bioethanol-derived acetylene/ethylene over supported WO<inf>3</inf> on silanol-rich silica prepared with Cu-leached copper phyllosilicate (CuPS). 20CuPS and 30CuPS were preliminarily reduced before Cu-leaching under an acidic solution (1 M HCl). Compared with fumed SiO<inf>2</inf>29Si CPMAS NMR spectroscopy showed an increase in surface silanols, particularly the isolated silanols (Q<inf>3</inf>), from removing Cu2+ octahedral sites (Cu2+(OSi)<inf>6</inf>) encapsulated within tetrahedral silica layers of CuPS. The surface silanols in fumed SiO<inf>2</inf>, 20CuPS-Le, and 30CuPS-Le adequately accommodate single-site and polymeric WO<inf>3</inf> species, leading to a similar 1,3-butadiene production rate (∼4.7 mmol h−1 g<inf>cat</inf>) at 5 wt% loading. Only 30CuPS-Le sufficiently provides the exposed silanols to disperse 8 wt% WO<inf>3</inf> loading without bulk WO<inf>3</inf> formation. The cross-metathesis activity depends on the relative amounts of exposed silanols. Accordingly, the steady 1,3-butadiene production was obtained in the order of 8WO<inf>3</inf>/30CuPS-Le (6.3 mmol h−1 g<inf>cat</inf>) > 8WO<inf>3</inf>/20CuPS-Le (5.1 mmol h−1 g<inf>cat</inf>) > 8WO<inf>3</inf>/SiO<inf>2</inf> (2.5 mmol h−1 g<inf>cat</inf>).
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Tuning Cu+ species/Brønsted acids of copper phyllosilicate by K+ doping for selective hydrogenation of methyl palmitate to hexadecanol
(2023-12-01)
Prasanseang, Warot
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Choojun, Kittisak
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Poo-arporn, Yingyot
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Huang, Ai Lin
;
Lin, Yu Chuan
Selective hydrogenation of methyl palmitate to hexadecanol can be manipulated by tuning Cu+ species and Brønsted acid sites (BAS) of copper phyllosilicate (CuPS) catalysts with K+ doping. The catalysts were prepared by impregnating K+ onto reduced and non-reduced CuPS. The reactions were carried out in a fixed-bed flow reactor at 250 °C under atmospheric H<inf>2</inf>. In situ TR-XANES and Py-IR suggest that the presence of K+ could stabilize Cu+ species and neutralize BAS. As compared to the non-reduced sample, K+ loading (0.01–0.10 wt%) on the reduced CuPS provide higher Cu+ fraction (10–16%), lower BAS (0.82 to 0.16μ mol/g) and lower Cu dispersion (75 to 52%). A balance between Cu0 active surface and Cu+ content provides an optimum hydrogenation activity (up to 80 %). The increased Cu+ species, together with the decreased BAS, does not only enhance the catalyst stability, but also hexadecanol selectivity (from 35 to 60%, at ∼50% conversion).
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Reversible Hydrogenation-Dehydrogenation of Acetylpyridine-Pd-MIL-101(Cr) for Chemical Hydrogen Storage
(2020-10-07)
Makmeesub, Nuttapong
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Ritvirulh, Chonlada
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Choojun, Kittisak
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Chen, Teng Hao
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Poo-Arporn, Yingyot
3-Acetylpyridine (AcP), as an organic hydrogen carrier, and Pd nanoparticles, as a catalyst, were incorporated into MIL-101(Cr) for chemical hydrogen storage. AcP was first grafted into MIL-101(Cr), and then Pd (0.5-4.0 wt %) was encapsulated by a double-solvent adsorption process. Thermogravimetric analysis, inductively coupled plasma-optical emission spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, in situ X-ray adsorption near-edge structure analysis, 1H nuclear magnetic resonance (NMR), and elemental analysis suggested the existence of AcP and Pd nanoparticles (NPs) inside the MIL-101(Cr) cages. The chemical hydrogen storage of samples was evaluated by H2 temperature-programmed reaction. In situ Fourier transform infrared and 1H NMR techniques verified the hydrogenated and dehydrogenated forms of AcP upon hydrogen uptake. Reversible hydrogenation/dehydrogenation can be readily regulated by H2 partial pressure and temperature. The chemical hydrogen storage could be accomplished only when AcP and Pd NPs were adjacently present. The chemical hydrogen storage was enhanced with an increased Pd loading up to 0.33 mmol H2·g-1 per cycle. With the manipulation of hydrogenation and dehydrogenation temperatures at 150 °C, the chemical hydrogen storage can be maintained for up to 10 cycles. The material reported herein is one of the noncryogenic chemical hydrogen storages that can be operated at constant temperature and atmospheric pressure.
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Direct conversion of glycerol to n-propanol over a tandem catalytic dehydration-hydrogenation system
(2022-06-30)
Solos, Thanasak
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Methiritthikul, Napanot
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Homla-Or, Chanakran
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Duangchan, Preedawan
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Choojun, Kittisak
The direct dehydration-hydrogenation of glycerol to n-propanol over a tandem catalytic system containing HZSM-5 (Si/Al ∼13) and supported Ni catalysts was studied under atmospheric H<inf>2</inf>. Complete glycerol conversion to acrolein and propionaldehyde (>82% selectivity) was optimized for dehydration in the first bed (HZSM-5) at 300 °C. Ni/MgO, Ni/SiO<inf>2</inf>, Ni/Mg-Al-LDH, Ni/TiO<inf>2</inf>, and Ni/Al<inf>2</inf>O<inf>3</inf> (20 wt% Ni loading) were used as hydrogenation catalysts in the second bed at 175 °C. Without the interference of glycerol from the first bed, the acrolein and propionaldehyde produced were hydrogenated to n-propanol (∼90% selectivity). Nevertheless, propanoic acid was observed as a minor product from water reduction by propionaldehyde. The cause of deactivation was investigated for the second beds (Ni/SiO<inf>2</inf>), where the formation of high MW products was evidenced. While the catalysts can be simply regenerated by calcining in air at 450 °C, HZSM-5¦20Ni/Al<inf>2</inf>O<inf>3</inf> with high Ni dispersion provides a higher stability and n-propanol yield (>73%) compared to other tandem catalysts.
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Highly active and stable Ni–W/SiO2 catalyst derived from W incorporated on Ni phyllosilicate for deoxygenation of triglycerides into green biofuel range hydrocarbons
(2025-10-01)
Praikaew, Wanichaya
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Prameswari, Jedy
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Ratchahat, Sakhon
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Chaiwat, Weerawut
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Sakdaronnarong, Chularat
Highly active and stable Ni–W/SiO<inf>2</inf> catalyst derived from W incorporated into Ni phyllosilicate (Ni-PS) was prepared by the ammonia evaporation (AE) method, and benchmarked with the catalyst prepared by the impregnation method (IM). Their catalytic activities were evaluated for deoxygenation of triglycerides into green biofuel-range hydrocarbons. The Ni-PS structure demonstrated a large surface area with strong interaction between Ni2+ and SiO<inf>2</inf>, resulting from the incorporation of Ni2+ into the silica framework, which led to highly dispersed Ni⁰ after H<inf>2</inf> reduction. Additionally, the H<inf>2</inf> adsorption and desorption capabilities, together with a substantial quantity of Lewis acid sites, were advantageous features of Ni-PS catalysts compared to Ni-IM and 5 W/Ni-IM catalysts. Ex situ and in situ structural characterizations revealed the generation of Ni⁰ and W⁰ states, along with remaining W4+ species after H<inf>2</inf> reduction. The 5 W/Ni-AE catalyst exhibited stable performance up to 60 h on stream, producing consistent yields of 30 % jet fuel and 40 % diesel, which was attributed to its high porosity, small Ni⁰ particle sizes, enhanced H<inf>2</inf> adsorption–desorption capacities, and abundant Lewis acid sites. Consequently, the heterogeneous 5 W/Ni-AE catalyst shows significant practical relevance for generating green biofuel from oil-derived feedstock in sustainable biorefineries.
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Linear long-chain α-olefins from hydrodeoxygenation of methyl palmitate over copper phyllosilicate catalysts
(2022-04-05)
Prasanseang, Warot
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Choojun, Kittisak
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Poo-arporn, Yingyot
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Huang, Ai Lin
;
Lin, Yu Chuan
Copper phyllosilicate (CuPS) was used as a bifunctional catalyst for hydrodeoxygenation of methyl palmitate (MP) to produce long-chain α-olefins without the loss of carbon backbone. The CuPS catalysts were prepared by ammonia evaporation-hydrothermal method. The crystal structure, surface area, reducibility, Cu dispersion, Cu particle size and acidity of the catalysts were examined by XRD, BET, H<inf>2</inf>-TPR, TEM, NH<inf>3</inf>-TPD and Py-IR. The existence of Cu2+ species (octahedral (O<inf>h</inf>)/square planar (Sq)), Cu+ and Cu0 upon calcination/reduction was investigated by in situ TR-XANES. The Cu dispersion was related to the Cu+ fraction in CuPS, while Brønsted acid sites (BAS) depends on Cu0 particles. The MP conversion to 1-hexadecene proceeds via hydrogenation-dehydration promoted by the synergy of Cu0 surface and Brønsted acid sites at the interface. The α-olefin selectivity depends on a balance between Cu+ and Cu loading. The 20CuPS possessing 10% Cu+ fraction, provides a high conversion of 72% with 45% α-olefin selectivity.
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Reversibly interconverted Cu+/Cu+-H species as active sites for selective hydrogenation of fatty acid methyl esters to fatty alcohol over layered double hydroxide derived CuMgAlOx catalysts
(2025-03-15)
Nooto, Chanisara
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Chuaykaew, Panalee
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Singthuen, Pawanrat
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Solos, Thanasak
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Preedawichitkun, Yardthip
High fatty alcohol production (>90 % selectivity) can be achieved though the selective hydrogenation of fatty acid methyl esters over layered double hydroxide derived CuMgAlO<inf>x</inf> catalysts in a fixed-bed reactor at 250 °C under atmospheric H<inf>2</inf>. ∼17 wt.% Cu loading CuLDHs with different Mg2+/Al3+ ratios (CuMg<inf>60</inf>Al<inf>40</inf>O<inf>x</inf>, CuMg<inf>70</inf>Al<inf>30</inf>O<inf>x</inf>, CuMg<inf>75</inf>Al<inf>25</inf>O<inf>x</inf>, and CuMg<inf>80</inf>Al<inf>20</inf>O<inf>x</inf>) were prepared by co-precipitation-hydrothermal method. The Cu dispersion and species were determined by H<inf>2</inf>-TPR, consecutive H<inf>2</inf>-TPR, N<inf>2</inf>O-dissociative reaction, and in situ TR-XANES. Highly dispersed Cu metal along with cationic Cu(I) species were obtained for all CuMgAlO<inf>x</inf>. The cationic Cu(I) species (Cu+/Cu+-H) content increased with Mg2+ content. In the presence of H<inf>2</inf>, the cationic Cu(I) species undergo reversible interconversion between Cu+ and Cu+-H species, facilitating hydrogen dissociation/evolution. The hydrogenation activity was governed by the balance of the metallic Cu surface and the cationic Cu(I) species. The Cu+ species allow preferential adsorption of C[dbnd]O ester for selective hydrogenation of FAMEs to fatty alcohol (>90 % selectivity). With Cu<inf>surface</inf>/Cu(I) ratio at 0.25 (CuMg<inf>75</inf>Al<inf>25</inf>O<inf>x</inf>), the fatty alcohol production rate of 49.3 h−1 was obtained with high stability due to the reversible interconversion of Cu+/Cu+-H that prevented product re-adsorption and side reactions.

Sooknoi, Tawan

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