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Bifunctional WOx/SiO2 catalysts for hydrogen-free upgrading of B100 and bio-ethylene to SAF and green diesel precursors via olefin metathesis and deoxygenation
(2026-09-15)
Solehudin, Mochamad
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Wengwirat, Kanokwan
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Promchana, Pratya
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Poo-arporn, Yingyot
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Limphirat, Wanwisa
This work presents a hydrogen-free catalytic route for upgrading palm-derived biodiesel (B100) into olefinic precursors for sustainable aviation fuel (SAF) and green diesel (GD) using bifunctional WO<inf>x</inf>/SiO<inf>2</inf> catalysts under atmospheric pressure. The catalysts integrate olefin cross-metathesis, mediated by surface W CH<inf>2</inf> species, with deoxygenation via Lewis-acidic W O sites, enabling selective C C bond exchange and C O bond cleavage without external hydrogen or noble metals. Detailed mechanistic studies revealed that methyl oleate (MO) rapidly undergoes cross-metathesis with ethylene to yield SAF-range C<inf>9</inf>–C<inf>14</inf> precursors, while methyl palmitate (MP) contributes primarily to GD (C<inf>15</inf>–C<inf>18</inf>) through ketene intermediates and decarbonylation–hydrogen transfer pathways. Contact time and temperature experiments confirmed that MO conversion is kinetically favored at milder conditions, whereas MP-derived pathways dominate at higher temperatures and extended residence times. Catalyst loading studies show that the 3 and 5 wt% WO<inf>x</inf>/SiO<inf>2</inf> catalysts are dominated by highly dispersed isolated and polymeric WO<inf>x</inf> species, which exhibit higher accessible acidity and consequently promote secondary cracking reactions. In contrast, the 8 wt% WO<inf>x</inf>/SiO<inf>2</inf> catalyst contains a higher fraction of bulk crystalline WO<inf>3</inf> domains, resulting in reduced surface acidity and suppressed cracking. Overall, 8 wt% WO<inf>x</inf>/SiO<inf>2</inf> delivers reasonable rates with high selectivity toward SAF/GD precursors, while minimizing secondary cracking. It can be regenerated and recycled with substantial recovery of catalytic performance, establishing a robust, low-pressure, and hydrogen-free pathway for scalable renewable fuel production from B100.
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Tailoring Re-loaded core–shell Ni structures embedded in mesoporous silica for the selective transformation of levulinic acid into γ-valerolactone
(2026-05-21)
Maneewong, Yupawan
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Lakhani, Pratikkumar
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Ratchahat, Sakhon
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Sakdaronnarong, Chularat
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Limphirat, Wanwisa
Heterogeneous core–shell catalysts have attracted significant interest because they integrate multiple catalytic functions within a single, precisely engineered architecture. In this work, we report the rational synthesis and catalytic evaluation of a Re-loaded Ni core–shell catalyst embedded in mesoporous silica for the efficient hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). The core–shell configuration enables effective confinement of Ni nanoparticles within the porous silica matrix and stabilizes spatially separated Ni and ReO<inf>X</inf> species with complementary catalytic functions. Comprehensive physicochemical characterization confirmed the successful formation of the core–shell structure, its high structural stability, and the presence of confined metallic Ni sites responsible for H<inf>2</inf> activation and oxophilic ReO<inf>X</inf>-derived acid sites for oxygenate activation. Under optimized conditions, the Ni<inf>12</inf>Re<inf>1.63</inf>-CS catalyst achieved complete LA conversion with a GVL yield exceeding 94% within 2 h, outperforming non-core-shell catalysts. The catalyst also displayed high intrinsic activity, with a turnover frequency of up to ∼36 h−1, and retained an excellent GVL selectivity of approximately 80% during recycling, despite a gradual decrease in LA conversion. These findings demonstrate that spatial separation of hydrogenation and oxophilic adsorption sites within a core–shell architecture is critical for enhancing activity and selectivity in biomass-derived platform molecule upgrading.
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Design of a rhenium-decorated mesoporous nickel phyllosilicate-derived Ni–Re/MCM-41 catalyst for efficient hydrogenation of levulinic acid to γ-valerolactone
(2026-04-27)
Maneewong, Yupawan
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Lakhani, Pratikkumar
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Ratchahat, Sakhon
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Sakdaronnarong, Chularat
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Limphirat, Wanwisa
Herein, Ni and NiRe catalysts supported on mesoporous MCM-41 were synthesized through ammonia evaporation (AE) and impregnation (IM) routes to explore structure–activity correlations in the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). The AE-derived nickel phyllosilicate (Ni-PS) framework provided strong interactions through Ni–O–Si linkages, leading to high dispersion and stabilization of Ni species. Incorporation of Re significantly improved reducibility, hydrogen activation, and the balance between acidic and metallic sites, resulting in enhanced catalytic efficiency. The optimized NiRe-PS catalyst exhibited a uniform nanostructure, strong Ni–Re synergy, and the highest metallic Ni fraction, which collectively promoted superior activity and stability. Under mild conditions (140 °C, 10 bar H<inf>2</inf>), NiRe-PS achieved complete LA conversion and ∼96% GVL yield within 4 h, with a turnover frequency of 26.3 h−1 (160 °C, 10 bar H<inf>2</inf>) and with an apparent rate constant of 0.0059 min−1. Mechanistic and isotopic investigations confirmed that both molecular and solvent-derived hydrogen contributed to the hydrogenation pathway. The exceptional activity, recyclability, and structural robustness of NiRe-PS demonstrate the potential of phyllosilicate-based bimetallic systems as efficient, non-noble catalysts for sustainable biomass valorization.
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Tuning spatially proximal Cu+ and Cu0 species via phyllosilicate coordination engineering for hydrogen-free upgrading of fatty acid methyl esters to fatty alcohols
(2026-01-01)
Khosukwiwat, Kanyanat
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Choojun, Kittisak
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Limphirat, Wanwisa
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Liu, Ting Hao
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Lin, Yu Chuan
Hydrogen-free upgrading of fatty acid methyl esters (FAMEs) to fatty alcohols offers a sustainable alternative to conventional hydrogenation but is limited by the inability to control metal speciation and interfacial acidity under catalytic transfer hydrogenation (CTH) conditions. A copper phyllosilicate (CuPS) is presented in which Cu loading (20–35 wt%) regulates the distribution of octahedral and square-planar Cu2+ species within the phyllosilicate structure, thereby governing reduction pathways, Cu+/Cu0 speciation, and surface acidity. Structural and in situ spectroscopic analyses (XRD, N<inf>2</inf> physisorption, TEM, and in situ TR-XANES) show that octahedral Cu2+ species embedded in Cu–O–Si layers preferentially generate and stabilize Cu+ sites upon reduction, whereas square-planar Cu2+ species favor Cu0 formation and particle growth. This coordination-dependent reducibility establishes a direct link between the CuPS precursor structure and the resulting Cu+/Cu0 ensemble and acid properties. As a result, 25CuPS, which maximizes retained octahedral Cu2+, forms the most effective spatially proximal Cu+ and Cu0 species, providing the highest Lewis acidity with suppressed Brønsted acidity and delivering the highest hexadecanol yield and methyl palmitate conversion. The catalytic behavior is consistent with cooperative ester activation on Cu+ sites and H-transfer from iso-propanol on adjacent Cu0 sites via a Meerwein–Ponndorf–Verley-type pathway. At higher Cu loadings, increased Cu0 domain growth and interfacial Brønsted acidity promote competing reactions and reduce alcohol selectivity. This work establishes coordination-controlled copper speciation as a materials design principle for hydrogen-free upgrading of biomass-derived esters.
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Stabilized Pd Nanoparticles Encapsulated in MIL-101(Cr) for Chemoselective Hydrogenation of Polyunsaturated FAMEs
(2025-11-24)
Preedawichitkun, Yardthip
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Numwong, Natthida
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Chanlek, Narong
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Chung, Po Wen
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Kumar, Raju
Palladium nanoparticles (Pd NPs) were successfully encapsulated within the porous framework of MIL-101(Cr) via a double solvent method to produce highly dispersed and stable catalysts for the chemoselective hydrogenation of polyunsaturated fatty acid methyl esters (FAMEs). Pd loadings ranging from 0.5 to 1.5 wt.% were systematically studied to elucidate the effects of nanoparticle size, dispersion, and hydrogen activation behavior on catalytic performance. The 0.8Pd/MIL-101(Cr) catalyst exhibited the highest turnover frequency (TOF ∼9,700 h−1) and superior selectivity (>90%) toward monounsaturated products (C18:1), attributed to optimal Pd dispersion. In contrast, the 0.5Pd/MIL-101(Cr) showed an induction period under low H<inf>2</inf> partial pressure, indicating limitations in hydride accommodation, while the 1.5Pd/MIL-101(Cr) suffered from Pd aggregation, resulting in a reduced intrinsic activity. Product selectivity was primarily governed by overall conversion: C18:1 was favored at low conversions, whereas C18:0 formation increased at higher conversions due to secondary hydrogenation. The catalysts demonstrated excellent stability and recyclability over multiple cycles without detectable Pd leaching or structural degradation. These findings establish MIL-101(Cr) as a robust and tunable platform for dispersing Pd NPs and highlight the potential of Pd/MIL-101(Cr) catalysts for efficient, selective upgrading of bioderived feedstocks under mild reaction conditions.
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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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Selective Hydrogenation of Polyunsaturated Fatty Acid Methyl Esters over Bifunctional Ligand-Modified Pd/MIL-101(Cr) Catalysts
(2025-09-22)
Khenkhom, Phuwadon
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Ritvirulh, Chonlada
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Choojun, Kittisak
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Preedawichitkun, Yardthip
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Chanlek, Narong
Highly dispersed palladium nanoparticles (Pd NPs) were incorporated into MIL-101(Cr) frameworks functionalized with bifunctional ligands for the liquid-phase hydrogenation of polyunsaturated fatty acid methyl esters (FAMEs). A series of amino- and carboxylic-acid-containing ligands─ethylenediamine (en), diethylenetriamine (DET), alanine (AN), 4-aminobutyric acid (ABA), 5-aminovaleric acid (AVA), glutamic acid (GA), and adipic acid (AA)─were grafted onto MIL-101(Cr), followed by Pd loading (0.5 wt %). Spectroscopic and structural analyses confirmed ligand coordination to both Cr nodes and Pd species. Catalysts bearing ABA, AVA, and GA exhibited Pd0dispersion (<1 nm), yielding high turnover frequencies (up to ∼15,400  h–1) and >94% selectivity for monounsaturated FAMEs. In contrast, strong Pd–N interactions in en- and DET-grafted materials suppressed Pd0formation, reducing activity. Hot filtration and recyclability tests confirmed high catalyst stability and negligible Pd leaching. The bifunctional ligand architecture effectively tunes Pd speciation and activity, providing a robust platform for selective and reusable hydrogenation catalysts.
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Hydrogen-Free Production of Green Diesel from Deoxygenation of Methyl Palmitate via Cross-Metathesis with Bio-Ethylene Using Supported WO3 Catalyst
(2025-06-02)
Solehudin, Mochamad
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Wengwirat, Kanokwan
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Promchana, Pratya
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Poo-arporn, Yingyot
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Limphirat, Wanwisa
Traditional green diesel production from used cooking oils faces challenges in H<inf>2</inf> supply and carbon loss as CO<inf>2</inf>. This study presents a novel hydrogen-free deoxygenation process via cross-metathesis between fatty acids/FAMEs and bio-ethylene under atmospheric pressure as an alternative sustainable solution. The carboxyl end group was removed as CO and blue hydrogen, bearing the hydrocarbons as green diesel, sustainable aviation fuel (SAF), and bio-naphtha. Bifunctional WO<inf>3</inf>/SiO<inf>2</inf> was prepared and characterized by XRD, XANES, EXAFS, DR-UV, and Raman. Lewis site (W = O) promotes the formation of ketene intermediate that undergoes cross-metathesis with ethylene over tungsten carbene (WCH<inf>2</inf>) sites, yielding a C16-ene majority with trace amounts of C17-ene. Smaller hydrocarbons (<C15) are obtained as minor components from decarbonylation, hydrogen transfer, and cracking. The increased contact time (27–106 g h/mol) at 460 °C results in increased conversion (30%–87 %), green diesel (12%–57%), SAF (3.5%–12.7%), and bio-naphtha (1.3%–5.3%). Optimal green diesel production of 2.92 h⁻¹ with 73% selectivity can be achieved at 480 °C. SAF and bio-naphtha yields can be tuned by varying temperature from 460 to 500 °C. This provides a sustainable pathway for renewable liquid fuels without an external hydrogen supply.
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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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