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Synergistic effects of bimetallic Co-SnOx species in selective hydrogenation of methyl oleate: The crucial role of reduction characteristics
(2026-09-01)
Sooknoi, Tawan
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Thainoi, Suwimon
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Chanakha, Vichuda
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Ausavasukhi, Artit
This study investigates the catalytic performance of bimetallic Co-Sn catalysts supported on alumina (Al<inf>2</inf>O<inf>3</inf>) for the selective hydrogenation of methyl oleate to oleyl alcohol. A strategic sequential reduction methodology, employing sodium borohydride followed by thermal hydrogen treatment (NaBH<inf>4</inf>-H<inf>2</inf>), was utilized to precisely tune the catalytic activity and chemoselectivity. Catalysts reduced solely with hydrogen at 300 °C exhibited limited efficiency, primarily favoring the formation of oleic acid via hydrogenolysis, which is attributed to the prevalence of cobalt oxide species. In contrast, the CoSnBH/Al<inf>2</inf>O<inf>3</inf> catalyst synthesized via a strategic sequential reduction methodology demonstrated a markedly enhanced selectivity toward oleyl alcohol, achieving a maximum selectivity of 54.1% at 270 °C and 8 MPa. Comprehensive characterization and kinetic analyses revealed that the superior performance stems from the synergistic coexistence of metallic cobalt (Co0) and low-valent tin oxides (SnO<inf>x</inf>), which form a bimetallic interface that preferentially polarizes the C=O bond. The catalytic efficiency was found to be highly sensitive to the nature of the support, the Co/Sn atomic ratio, and the total metal loading. Notably, turnover frequency (TOF) analysis indicated that while increased loading improves conversion, it may lead to site agglomeration and a reduction in surface-active concentration. Mechanistically, we propose that the CoSnBH/Al<inf>2</inf>O<inf>3</inf> system facilitates a direct hydrogenation pathway to oleyl alcohol, effectively bypassing the formation of heavy ester intermediates typically reported in literature.
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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.
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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
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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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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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Effect of pd precursor salts on the chemical state, particle size, and performance of activated carbon-supported pd catalysts for the selective hydrogenation of palm biodiesel
(2021-02-01)
Udomsap, Parncheewa
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Eiad-Ua, Apiluck
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Chen, Shih Yuan
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Mochizuki, Takehisa
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Chollacoop, Nuwong
To improve the oxidative stability of biodiesel fuel (BDF), the polyunsaturated fatty acid methyl esters (poly-FAME) presented in commercial palm oil-derived biodiesel fuel (palm-BDF) were selectively hydrogenated to monounsaturated fatty acid methyl esters (mono-FAME) under a mild condition (80 °C, 0.5 MPa) using activated carbon (AC)-supported Pd catalysts with a Pd loading of 1 wt.%. The partially hydrotreated palm-BDF (denoted as H-FAME) which has low poly-FAME components is a new type of BDF with enhanced quality for use in high blends. In this study, we reported that the chemical states and particle sizes of Pd in the prepared Pd/AC catalysts were significantly influenced by the Pd precursors, Pd(NO3)2 and Pd(NH3)4Cl2, and thus varied their hydrogenation activity and product selectivity. The 1%Pd/AC (nit) catalyst, prepared using Pd(NO3)2, presented high performance for selective hydrogenation of poly-FAME into mono-FAME with high oxidation stability, owning to its large Pd particles (8.4 nm). Conversely, the 1%Pd/AC (amc) cata-lyst, prepared using Pd(NH3)4Cl2, contained small Pd particles (2.7 nm) with a little Cl residues, which could be completely removed by washing with an aqueous solution of 0.1 M NH4OH. The small Pd particles gave increased selectivity toward unwanted-FAME components, particularly the saturated fatty acid methyl esters during the hydrogenation of poly-FAME. This selectivity is un-profitable for improving the biodiesel quality.
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Development of bimetallic Ni-Cu/SiO2 catalysts for liquid phase selective hydrogenation of furfural to furfuryl alcohol
(2021-01-15)
Weerachawanasak, Patcharaporn
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Krawmanee, Pacharaporn
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Inkamhaeng, Weerachat
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Cadete Santos Aires, Francisco J.
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Sooknoi, Tawan
Bimetallic Ni-Cu/SiO<inf>2</inf> catalysts with different Cu loading (2–5 wt%) were developed for liquid phase selective hydrogenation of furfural to furfuryl alcohol. Among these, bimetallic 2%Ni-X%Cu/SiO<inf>2</inf> (X = 2, 5) catalysts exhibited better catalytic performances than monometallic 2%Ni/SiO<inf>2</inf> and 2%Cu/SiO<inf>2</inf>. Moreover, the bimetallic 2%Ni-5%Cu/SiO<inf>2</inf> catalyst showed the best catalytic performance with 94% of furfural conversion and 64% of furfuryl alcohol selectivity. The synergetic effect of NiCu alloy particles that are present on bimetallic Ni-Cu/SiO<inf>2</inf> catalysts change the adsorption configuration of furfural on the catalyst surface resulting in high catalytic performance in liquid phase selective hydrogenation of furfural to furfuryl alcohol.
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Flame spray-synthesized Pt-Co/TiO2 catalysts for the selective hydrogenation of furfural to furfuryl alcohol
(2021-01-15)
Tolek, Weerachon
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Khruechao, Kitima
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Pongthawornsakun, Boontida
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Mekasuwandumrong, Okorn
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Cadete Santos Aires, Francisco José
Flame spray-synthesized Pt/TiO<inf>2</inf> and PtCo/TiO<inf>2</inf> catalysts with 0.7 wt% Pt and 0–0.4 wt% Co were studied in the hydrogenation of furfural to furfuryl alcohol (FA) at 50 °C and 2 MPa H<inf>2</inf>. Particle formation under high temperature flame facilitated high Pt dispersion and formation of Pt-TiO<inf>x</inf> interface sites, which were beneficial for furfural conversion to FA. Modifying with Co accelerated rutile phase TiO<inf>2</inf> formation, which strongly diminished hydrogenation activity on the (FSP)-PtCo/TiO<inf>2</inf>. On the other hand, (I)-PtCo/TiO<inf>2</inf> prepared by conventional impregnation, anatase phase TiO<inf>2</inf> was preserved (> 85%) and both furfural conversion and FA selectivity increased upon increasing Co loading.

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