Ritvirulh, Chonlada

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Ritvirulh, Chonlada
Alternative Name
Ritvirulh, C.
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Email
chonlada.ri@kmitl.ac.th

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    Reversible Hydrogenation-Dehydrogenation of Acetylpyridine-Pd-MIL-101(Cr) for Chemical Hydrogen Storage
    (2020-10-07)
    Makmeesub, Nuttapong
    ;
    Ritvirulh, Chonlada
    ;
    Choojun, Kittisak
    ;
    Chen, Teng Hao
    ;
    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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    Highly stable Pd2+ species anchoring on ethylenediamine-grafted-MIL-101(Cr) as a robust oxidation catalyst†
    (2022-02-01)
    Makmeesub, Nuttapong
    ;
    Ritvirulh, Chonlada
    ;
    Choojun, Kittisak
    ;
    Sattayaporn, Suchinda
    ;
    Resasco, Daniel E.
    Highly stable Pd<sup>2+</sup> species were anchored on ethylenediamine-grafted MIL-101(Cr). Ethylenediamine (0.3-1.2 mmol g<sup>−1</sup>) was first grafted onto MIL-101(Cr), then Pd<sup>2+</sup> (0.03-0.2 mmol Pd per g) was incorporated by double-solvent adsorption. Fourier transform infrared, inductively coupled plasma-optical emission spectroscopy, transmission electron microscopy and CHN analysis confirmed the incorporation of ethylenediamine and Pd<sup>2+</sup> in MIL-101(Cr). X-ray photoelectron and Raman spectroscopy suggested that one amino moiety of ethylenediamine coordinated with the Cr<sup>3+</sup> nodes of MIL-101(Cr). The other served as an anchoring site for the incorporated Pd<sup>2+</sup> species. In situ X-ray absorption near-edge structure analysis showed that the strong interaction between Pd<sup>2+</sup> and ethylenediamine, within the confinement of the MIL-101(Cr) structure, effectively prevented reduction to Pd<sup>0</sup>, even in the presence of H<inf>2</inf> at 150 °C. At relatively low temperatures, the catalysts with ethylenediamine : Pd<sup>2+</sup> molar ratios of 10 provided a higher activity for styrene oxidation (TOF ∼30 h<sup>−1</sup>), as compared to previous reports. The presence of ethylenediamine as an anchoring ligand also inhibited the reduction of Pd<sup>2+</sup> by the feed (styrene) and minimized leaching of the active Pd<sup>2+</sup> species under oxidizing and acidic conditions. The Pd<sup>2+</sup> species anchoring on ethylenediamine-grafted-MIL-101(Cr) exhibited an improved catalytic activity and stability, as compared to typical liquid-phase oxidation catalysts.
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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
    ;
    Ritvirulh, Chonlada
    ;
    Choojun, Kittisak
    ;
    Preedawichitkun, Yardthip
    ;
    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 Pd<sup>0</sup>dispersion (&lt;1 nm), yielding high turnover frequencies (up to ∼15,400  h<sup>–1</sup>) and &gt;94% selectivity for monounsaturated FAMEs. In contrast, strong Pd–N interactions in en- and DET-grafted materials suppressed Pd<sup>0</sup>formation, 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.