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Dual HER-OER performance during alkaline water splitting found in CrMnFeCo-based high-entropy materials
(2026-06-01)
Somdee, Siriwimol
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Saelee, Tinnakorn
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Khajondetchairit, Patcharaporn
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Ektarawong, Annop
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Kheawhom, Soorathep
The development of high-efficiency electrocatalyst for hydrogen production via electrochemical water splitting is crucial for advancing renewable energy technologies. However, the sluggish kinetics of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remain significant challenges. In this study, CrMnFeCoX high-entropy materials (HEMs; X = Cu, Ga, P, and Zn) are investigated as electrocatalysts for overall water splitting in alkaline media using density functional theory calculations. These HEMs are modeled using the special quasi-random structure method with a face-centered cubic (111) structure. The results revealed that the OER activity cannot be sustained due to strong adsorption of oxygenated intermediates. Specifically, the dissociation of the O-O bond in the *OOH intermediate leads to surface oxidation, which decreases activity, evidenced by the d ( p )-band center shift. Consequently, HER activity is analyzed on pristine surfaces, whereas OER activity is evaluated on oxide surfaces. The CrMnFeCoCu surface exhibits excellent HER activity, achieving a low overpotential of 0.03 V vs. RHE, attributed to effective water dissociation and moderate *H adsorption energies. Meanwhile, the CrMnFeCoP surface demonstrates superior OER activity with an overpotential of 0.39 V vs. RHE, driven by its moderate adsorption energies for oxygenated intermediates. Site-specific analyses identify Cu and Co as the primary active sites for HER and OER, respectively. These findings highlight CrMnFeCoCu and CrMnFeCoP as promising candidates for the rational design of efficient electrocatalysts for HER and OER in electrochemical water splitting.
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Unraveling H2 dissociation in CO2 hydrogenation on frustrated Lewis pair-functionalized UiO–67: DFT and nuclear quantum effects
(2025-12-04)
Yodsin, Nuttapon
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Udagawa, Taro
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Daengngern, Rathawat
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Jungsutthiwong, Siriporn
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Tachikawa, Masanori
Understanding hydrogen (H<inf>2</inf>) activation is fundamental to developing efficient CO<inf>2</inf> hydrogenation catalysts. Thus, in this study, we examine H<inf>2</inf> dissociation and subsequent CO<inf>2</inf> hydrogenation on 12 UiO–67 frameworks functionalized with frustrated Lewis pairs (FLPs), employing both conventional density functional theory (DFT) and multicomponent DFT (MC_DFT) to account for nuclear quantum effects (NQEs). The results reveal that all FLP–MOFs lower the H<inf>2</inf> activation barrier through heterolytic cleavage, with NQEs further reducing the barriers—most notably in systems containing electron-donating groups (EDGs), where pronounced H–H bond elongation characterizes the transition state. Conversely, FLPs bearing strong electron-withdrawing groups stabilize the 2H adsorption state, rendering H<inf>2</inf> dissociation thermodynamically favorable but suppressing CO<inf>2</inf> hydrogenation owing to excessively strong hydrogen binding. Strong correlations are observed among H<inf>2</inf> dissociation energies, CO<inf>2</inf> hydrogenation activation barriers, and FLP acidity, enabling catalytic performance prediction. Incorporating NQEs enhances these correlations, providing a refined descriptor for rational catalyst screening. Overall, this study highlights the critical role of NQEs in hydrogen activation and demonstrates that EDG-functionalized FLP–MOFs are particularly promising candidates for promoting H<inf>2</inf> activation and CO<inf>2</inf> conversion.
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Synergistic effect of arsenic removal from petroleum condensate via liquid-liquid extraction: Thermodynamics, kinetics, DFT and McCabe-Thiele method
(2023-12-01)
Purktimatanont, Kittamuk
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Mohdee, Vanee
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Pancharoen, Ura
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Maneeintr, Kreangkrai
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Punyain, Wikorn
This work presents the purification of petroleum condensate by removing arsenic ions via liquid-liquid extraction (LLE). Influence of pure and synergistic extractants is investigated. In terms of the practicability, following parameters are examined: the type of extractant, operating time, and temperature. Response surface methodology is used to design parameters such as organic-aqueous ratio and extractant concentration. Under optimal conditions; a mixture of 1 mol/L HCl and 0.02 mol/L thiourea with an organic/aqueous ratio of 1:4 at 323.15 K for 60 min, the extraction of arsenic reached 78.2 %. Further, batch simulation via two-stage counter-current extraction, and estimation by McCabe-Thiele diagram proved to be enhanced arsenic extraction to 95.3 %. Analysis by FTIR show that arsenic ions in petroleum condensate are formed as triphenylarsine compound ((C<inf>6</inf>H<inf>5</inf>)<inf>3</inf>As). The process of arsenic removal proved to be zero-order endothermic, irreversible and spontaneous reaction. The results obtained from the density functional theory (DFT) confirm that arsenic ions react with the synergistic extractant: effectively forming a covalent bond (As–S).
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Ultrahigh hydrogen storage using metal-decorated defected biphenylene
(2023-08-30)
Kaewmaraya, T.
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Thatsami, N.
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Tangpakonsab, P.
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Kinkla, R.
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Kotmool, K.
Hydrogen (H<inf>2</inf>) energy has emerged as a principal contender for renewable green energy applications because of the ultra-high energy density and natural abundance. The implementation of this prospective technology necessitates the ultra-high capacity of H<inf>2</inf> storage mediums. This work reports the exceptional H<inf>2</inf> storage capacities of two-dimensional (2D) carbon allotrope biphenylene (BPL) functionalized by Li, Na, K, and Ca. The combined theoretical approaches including the density functional theory (DFT), ab-initio molecular dynamics (AIMD), maximally localized Wannier functions (MLWFs), and thermodynamic analysis were employed to elucidate the storage efficiencies at operationally practical conditions. The findings reveal that pristine BPL decorated by the selected metals are all inefficient for H<inf>2</inf> storage because of the sensitive crystal instability caused by the energetic aggregation of the metallic dopants. On the other hand, point-defected BPL resolves this issue because it adequately magnifies the binding energies with all the decorated metals via the highly ionic bonds. Crucially, these binding energies exceed the cohesive counterparts of the parental metal bulks, consequently stabilizing the crystal integrity. Intriguingly, the Li- and Na-decorated divacancy BPL retain the ultimate H<inf>2</inf> storage capacities of 6.76 wt% and 6.66 wt% at the practical temperature and pressure, respectively, surpassing the goal value of 5.50 wt% to be achieved by 2025. Hence, metal-functionalized BPL are conclusively the promising carbon materials for the H<inf>2</inf> storage functionality.
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Nature of electronic topological transition and superconductivity in bismuth under high pressure from ab initio random structure searching
(2021-12-01)
Chaimayo, Wanaruk
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Tsuppayakorn-aek, Prutthipong
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Pluengphon, Prayoonsak
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Kotmool, Komsilp
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Pakornchote, Teerachote
We have predicted the hexagonal close-packed (hcp) structure of bismuth (Bi) using ab initio random structure searching (AIRSS) at extreme conditions. The calculation, which included spin–orbit coupling, shows that the hcp structure is thermodynamically and dynamically stable at high pressure. The electronic band structure calculations suggest the downshifting of the flat band through compression due to Lifshitz transitions. The Fermi surface shape of hcp Bi produces the metallicity in this material. The electron localization function reveals a weak bonding of Bi. The solutions of electronic topological transition and a soft-mode of phonon dispersion provide the possibility for prediction and reduction of the superconducting transition temperature.

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