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First-Principles Study of Ti2NbC2T2 (T = F, O) MXene for Inhibiting Shuttle Effect in Na–S Batteries
(2026-07-23)
Udomkijmongkol, Anan
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Thasitha, Sirinee
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Wongphen, Kantaphong
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Khammuang, Satchakorn
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Scheicher, Ralph H.
Sodium–sulfur (Na–S) batteries offer great promise for large-scale energy storage due to their high theoretical energy density and cost-effectiveness; however, their practical performance is limited by the severe shuttle effect of soluble sodium polysulfides (Na<inf>2</inf>S<inf>n</inf>). In this work, we employ density functional theory (DFT) to investigate the structural and electronic properties of Ti<inf>2</inf>NbC<inf>2</inf>T<inf>2</inf> (T = F, O) MXenes, a recently synthesized and experimentally verified member of the MXene family. Adsorption energy calculations show that O termination significantly enhances the binding affinity toward Na<inf>2</inf>S<inf>n</inf> compared to F termination. Electronic structure analyses reveal strong hybridization between Na-s and S-p orbitals of polysulfides and the Ti<inf>2</inf>NbC<inf>2</inf>T<inf>2</inf> surface, with low-order Na<inf>2</inf>S<inf>n</inf> exhibiting notable S-p band shifts that increase metallicity upon adsorption. Charge density difference and Bader charge analyses confirm substantial electron transfer from Na<inf>2</inf>S<inf>n</inf> to Ti<inf>2</inf>NbC<inf>2</inf>T<inf>2</inf>, particularly for O-terminated surface, indicative of robust Na–S chemical bonding. Conversely, S<inf>8</inf> displays minimal charge redistribution, consistent with weak physisorption. These results highlight Ti<inf>2</inf>NbC<inf>2</inf>O<inf>2</inf> as an experimentally accessible and highly effective MXene host capable of strongly anchoring sodium polysulfides and suppressing their dissolution, thereby mitigating the shuttle effect in Na–S batteries. This study provides fundamental insights into MXene and polysulfide interfacial chemistry and offers a valuable design strategy for next-generation Na–S host cathode materials.
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A magnetic nanosensor for flammable VOCs detection: unveiling Mn2SO2 monolayer performance through ab initio modelling
(2026-06-30)
Oo, Ghaim Man
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Khammuang, Satchakorn
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Udomkijmongkol, Anan
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Thasitha, Sirinee
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Ounrit, Iyarat
Effective victim detection during fire disasters requires reliable identification of flammable VOCs under high-temperature conditions. Magnetic VOC sensors based on two-dimensional nanomaterials offer a promising solution. In this work, a Mn<inf>2</inf>SO<inf>2</inf> monolayer is investigated as a magnetic VOC sensor for eleven fire-related VOCs using density functional theory (DFT). Mn<inf>2</inf>SO<inf>2</inf> exhibits intrinsic spin polarization and ferromagnetism that support magnetic sensing. Adsorption results show strong chemisorption for Benzaldehyde, Butanol, Heptane, Hexanal, Methylamine, Dimethyl disulfide, Dimethyl trisulfide, Pyridine, and Toluene, with adsorption energies from −1.53 to −0.46 eV, whereas Butanone (−0.34 eV) and Octane (−0.12 eV) show weak physisorption. Charge transfer, electron density difference, and ELF analyses reveal predominantly ionic interactions, with Mn<inf>2</inf>SO<inf>2</inf> acting as an electron acceptor. Sensor responsiveness assessed via work-function modulation and magnetic-moment variation indicates high sensitivity, particularly for Pyridine (42.81%), Dimethyl disulfide (33.07%), Butanol (15.57%), and Toluene (15.84%). Ab initio molecular dynamics at 400 K confirm thermal stability and structural integrity on the picosecond timescale. Pyridine and Dimethyl disulfide emerge as the most promising detection targets due to high sensitivity and fast recovery times. These results highlight Mn<inf>2</inf>SO<inf>2</inf> as a promising candidate for the future generation of magnetic VOC sensors in fire-disaster victim detection.
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Mechanistic understanding of transition-metal-decorated biphenylene for highly selective NO2 and NH3 detection
(2026-06-15)
Wongphen, Kantaphong
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Khammuang, Satchakorn
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Oo, Ghaim Man
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Hussain, Tanveer
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Kotmool, Komsilp
Here, we employ density functional theory (DFT) in combination with ab initio molecular dynamics (AIMD) simulations to examine the sensing performance of biphenylene doped with selected transition-metal dopants (M@BP), specifically Fe, Co, and Ni, on NO<inf>2</inf> and NH<inf>3</inf>. The results indicate that NO<inf>2</inf> exhibits stronger interaction than NH<inf>3</inf>, with adsorption energies ( E<inf>ads</inf> ) exceeding -3.0 eV. In contrast, the E<inf>ads</inf> values for NH<inf>3</inf> are around -1.30 eV. Bader charge and electron density difference (EDD) analyses reveal that charge is transferred from the M@BP monolayers to NO<inf>2</inf>. In contrast, the charge transfer occurs in the opposite direction for NH<inf>3</inf>, indicating distinct chemical adsorption mechanisms. Additionally, the electron localization function (ELF) results indicate partial ionic bonding and localized charge sharing between the metal sites of M@BP and the gas molecules. Variations in the work function, alongside calculated sensitivity (S) values, demonstrate that M@BP is exceptionally responsive to NH<inf>3</inf>, with S values of 13.4 %, 8.7 %, and 13.7 % for Fe@BP, Co@BP, and Ni@BP, respectively. These materials exhibit strong potential as reusable gas sensors capable of operating at temperatures above 500 K while maintaining practical recovery times. Moreover, AIMD simulations confirm the thermal stability of Co@BP and Ni@BP, whereas Fe@BP exhibits instability at 600 K. These findings suggest that M@BP possess a strong affinity for NH<inf>3</inf>, tunable electronic properties, and excellent thermal stability, making them promising candidates for selective, reusable high-temperature gas-sensor applications.
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Metal anchoring-induced enhancement of Ψ-graphene gas sensors for CH4, CO, and CO2 monitoring
(2026-05-01)
Khammuang, Satchakorn
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Wongphen, Kantaphong
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Hussain, Tanveer
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Kotmool, Komsilp
Metal-anchored Ψ-graphene (Ψ-G@M; M = Cu, Ag, Pd, and Pt) systems were systematically investigated using first-principles calculations to assess their structural stability, electronic properties, and gas-sensing performance toward CH<inf>4</inf>, CO, and CO<inf>2</inf>. Structural analysis indicates that all metal atoms can be stably anchored on the Ψ-graphene surface, with stability following the order Pt > Pd > Cu > Ag based on formation energies and adsorption distances. Electronic structure analyses, including partial density of states (PDOS), electron density difference (EDD), Bader charge, and electron localization function (ELF), reveal stronger orbital hybridization between Pd and Pt with the C-2p states of Ψ-graphene, suggesting partially covalent interactions, whereas Cu and Ag exhibit weaker hybridization and more localized electronic distributions. All metal-anchored systems preserve the intrinsic non-magnetic character of Ψ-graphene. Gas adsorption results demonstrate that CH<inf>4</inf> adsorption on Ψ-G@Cu, Ψ-G@Pd, and Ψ-G@Pt, CO adsorption on Ψ-G@Ag, and CO<inf>2</inf> adsorption on Ψ-G@Cu, Ψ-G@Pd, and Ψ-G@Pt fall within the optimal adsorption energy range (-0.50 to -1.20 eV), providing a suitable balance between adsorption strength and reversible desorption for sensing applications. In contrast, the exceptionally strong adsorption of CO on Ψ-G@Cu, Ψ-G@Pd, and Ψ-G@Pt suggests that these systems are more suitable for gas capture than for reversible sensing. Work function modulation and sensitivity analyses reveal that CH<inf>4</inf> adsorption on Ψ-G@Cu and CO<inf>2</inf> adsorption on Ψ-G@Cu, Ψ-G@Pd, and Ψ-G@Pt exhibit sensitivity values exceeding 10%, indicating significant electronic responses upon gas adsorption. Recovery time calculations further demonstrate rapid desorption of CH<inf>4</inf> on Ψ-G@Cu and Ψ-G@Pd, and of CO<inf>2</inf> on Ψ-G@Cu and Ψ-G@Pd, at 300 K, suggesting excellent reversibility and fast sensing capability. Ab initio molecular dynamics simulations confirm that the sensing systems, CH<inf>4</inf>-Ψ-G@Cu and CO<inf>2</inf>-Ψ-G@Pd, remain structurally stable at both 300 K and 500 K, demonstrating strong thermal stability under operating and regeneration conditions. These findings highlight that Cu- and Pd-anchored Ψ-graphene are promising candidates for high-performance CH<inf>4</inf> and CO<inf>2</inf> gas sensing with high sensitivity, rapid recovery, and robust thermal stability.
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Inhibiting the shuttle effect in sodium-sulfur batteries using Mo2CT2(T = S, O) MXenes: A DFT investigation
(2026-03-30)
Udomkijmongkol, Anan
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Ruttanapunt, Piyaphat
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Thasitha, Sirinee
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Ounrit, Iyarat
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Khammuang, Satchakorn
The rising demand for electrification has highlighted sodium–sulfur (Na–S) batteries as a promising energy-storage technology due to their high theoretical capacity, abundant materials, and low cost. However, their performance is limited by polysulfide dissolution, or the shuttle effect, which slows redox kinetics and accelerates capacity fading. This study employs the DFT method to investigate Mo<inf>2</inf>CT<inf>2</inf> (T = S, O) MXenes in 1T and 2H phases as potential anchoring materials for sulfur cathodes. All Mo<inf>2</inf>CT<inf>2</inf> structures effectively adsorb sodium polysulfides (Na<inf>2</inf>S<inf>n</inf>), demonstrating higher adsorption strength than commercial electrolytes and effectively suppressing the shuttle effect. Structural phase notably affects Na<inf>2</inf>S<inf>n</inf> adsorption on Mo<inf>2</inf>CS<inf>2</inf>, while its influence is minor for Mo<inf>2</inf>CO<inf>2</inf>. Higher Na<inf>2</inf>S<inf>n</inf>-Mo<inf>2</inf>CO<inf>2</inf> interaction arises from greater charge transfer from Na to O atom driven by higher electronegativity difference. Among the candidates, 2H-Mo<inf>2</inf>CS<inf>2</inf> and 1T-Mo<inf>2</inf>CO<inf>2</inf> exhibit higher binding energies than its counterpart and maintain metallic conductivity after Na<inf>2</inf>S<inf>n</inf> adsorption, benefiting electron transport. Gibbs free energy calculations indicate more favorable sulfur reduction pathways on Mo<inf>2</inf>CT<inf>2</inf> surfaces, along with reduced energy barriers for Na<inf>2</inf>S oxidation. Overall, Mo<inf>2</inf>CT<inf>2</inf> MXenes exhibit strong anchoring capability and catalytic activity, making them promising materials for mitigating the shuttle effect and enhancing electrochemical performance in Na–S batteries.
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Ab initio investigation of NO capture by Fe/Co/Ni‑doped biphenylene monolayers
(2026-02-15)
Wongphen, Kantaphong
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Khammuang, Satchakorn
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Hussain, Tanveer
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Kotmool, Komsilp
We employ first-principles density functional theory (DFT) calculations to explore the potential of Fe-, Co–, and Ni-doped biphenylene (BP) monolayers as efficient materials for nitric oxide (NO) gas detection and capture. Our results reveal strong chemisorption of NO gas, with adsorption energies of −2.820, −2.016, and −2.504 eV, respectively. Spin-polarized partial density of states (PDOS) analysis indicates notable magnetic modulation upon NO adsorption, particularly the quenching of spin in Fe-doped BP and induced asymmetric spin polarization in Co– and Ni-doped systems. Charge transfer analysis, as determined by Bader charge, electron density difference (EDD), and electron localization function (ELF), confirms significant electron donation from the doped surfaces to the NO molecule, correlating with an enhanced adsorption strength. Metal doping significantly reduces the work function (ϕ) value of the BP monolayer, while subsequent NO adsorption slightly increases due to electron transfer from the metal dopants to the NO gas. Moreover, ab initio molecular dynamics (AIMD) simulations at 300 K demonstrate the thermal stability of the NO-adsorbed configurations, reinforcing the feasibility of these systems under ambient temperature. Collectively, our findings highlight the strong interaction between NO gas and metal-doped BP monolayers (M@BP), underscoring their promise for advanced NO gas storage and sensing technologies.
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Modulating WS2 surface reactivity via Nb decoration: A DFT study of gas interaction, sensing, and storage potential
(2026-01-15)
Wongphen, Kantaphong
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Ruttanapunt, Piyaphat
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Khammuang, Satchakorn
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Hussain, Tanveer
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Kotmool, Komsilp
In this study, we employ first-principles density functional theory (DFT) to investigate the electronic, magnetic, and thermodynamic properties of niobium-decorated tungsten disulfide (Nb@WS<inf>2</inf>), a potential material for gas capture and sensing. The adsorption behavior of CO, HCHO, NO, and NO<inf>2</inf> was systematically investigated. Adsorption energies (E<inf>ads</inf>) range from −1.481 eV (CO) to −3.290 eV (NO<inf>2</inf>), with NO<inf>2</inf> exhibiting the strongest interaction due to the high difference in electronegativity between interacting N and Nb atoms. Partial density of states (PDOS), Bader charge analysis, electron density difference (EDD), and electron localization function (ELF) collectively reveal significant charge transfer from Nb@WS<inf>2</inf> to gas molecules, confirming the chemisorption nature of the interactions and the emergence of distinct electronic and magnetic signatures. Work function analysis showed notable increases upon gas adsorption, correlating with sensitivity enhancements of up to 18.24 % for NO. However, the elevated E<inf>ads</inf> values observed in these systems, leading to their enormous recovery times, pose specific challenges for their practical use as reusable gas sensors. Moreover, ab initio molecular dynamics (AIMD) simulations at 500 K confirm the thermal stability of gas-adsorbed configurations, reinforcing the viability of Nb@WS<inf>2</inf> for high-temperature sensing or capturing applications.
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Unveiling the potential of Mo2C and Mo2CO2MXenes for Na-ion batteries: An ab initio study
(2026-01-01)
Khammuang, Satchakorn
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Kaewmaraya, Thanayut
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Hussain, Tanveer
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Kotmool, Komsilp
This study employs density functional theory (DFT) calculations to investigate the potential of Mo<inf>2</inf>C and Mo<inf>2</inf>CO<inf>2</inf>MXenes as promising anode material candidates for Na-ion batteries under varying biaxial strains. The findings indicate that O-termination significantly enhances the Na adsorption energy compared to bare Mo<inf>2</inf>C, due to a stronger O-Na interaction. Under compressive strain, the diffusion energy barrier decreases while it increases under tensile strain for both forms of Mo<inf>2</inf>C-based MXenes. Ab initio molecular dynamics (AIMD) simulations at 300 K, which verify the thermal stabilities of both calculated MXenes, suggest their maximum theoretical capacities at operational temperatures, calculated to be 131.43 mAh/g for Mo<inf>2</inf>C and 227.21 mAh/g for Mo<inf>2</inf>CO<inf>2</inf>. The open-circuit voltages (OCV) calculated from DFT total energies for the Na loadings retained after AIMD. The OVC is in the optimal range of 0–1.0 V, which helps prevent dendrite formation. The OCV values of 0.47 V for Mo<inf>2</inf>C and 0.65 V for Mo<inf>2</inf>CO<inf>2</inf>highlight their suitability as anodes. These results show that Mo<inf>2</inf>C and Mo<inf>2</inf>CO<inf>2</inf>have low energy barriers, high structural stability, and low OCV values, making them promising candidates for Na-ion battery anodes with properties that can be adjusted through biaxial strain modifications.
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First-principles study insights into Janus MoWC-based MXenes for enhanced H2S and NH3 sensing applications
(2025-08-01)
Khammuang, Satchakorn
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Udomkijmongkol, Anan
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Thasitha, Sirinee
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Hussain, Tanveer
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Kotmool, Komsilp
Gas sensors are vital for environmental monitoring, industrial safety, and public health, enabling the detection of hazardous gases like H<inf>2</inf>S and NH<inf>3</inf>, even at low concentrations. This study uses first-principles calculations to investigate the gas-sensing properties of H<inf>2</inf>S and NH<inf>3</inf> gases on MoWC and MoWCO<inf>2</inf>, revealing key insights into their interaction mechanisms and potential for sensor applications. MoWC demonstrates stronger interactions with the gases compared to MoWCO<inf>2</inf>, as indicated by higher adsorption energy values. Charge transfer and electron density analysis suggest that the adsorption is primarily driven by charge exchange. The findings indicate that MoWC exhibits a highly sensitivity, undergoing significant work function changes when gas is adsorbed. However, AIMD results indicate that at 500 K, hydrogen atoms from gases attract to the surface and form terminal groups, making it unsuitable as a toxic gas sensor under these conditions. In contrast, MoWCO<inf>2</inf> exhibits too fast reversibility with an extremely short recovery time. In addition, we demonstrate that the sensing performance is enhanced by introducing O-vacancies in MoWCO<inf>2</inf>. The MoWCO<inf>2-vac</inf> shows increased adsorption energy for H<inf>2</inf>S and offers appropriate recovery times of 0.330 s with a sensitivity of 7.547 %, making it a suitable candidate for efficient room-temperature sensors. These findings pave the way to improve the potential of Janus MoWC-based MXenes for advanced H<inf>2</inf>S and NH<inf>3</inf> sensing applications.
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Role of Cu Substitute in AgGaTe2 in Structural Stabilities, Electronic Property, and High-Pressure Phase Transitions: A DFT Investigation
(2025-06-19)
Ounrit, Iyarat
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Khammuang, Satchakorn
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Udomkijmongkol, Anan
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Thasitha, Sirinee
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Sakulkalavek, Aparporn
The Cu-Ag-Ga-Te system has garnered significant attention due to its promising properties, including excellent photoelectric and thermoelectric characteristics. This study investigates the effects of substitutional Cu doping into AgGaTe<inf>2</inf> at a 1:1 ratio of Ag and Cu on the structural stabilities and electronic and mechanical properties using density functional theory (DFT) calculations. All calculated results are compared to those of AgGaTe<inf>2</inf> and CuGaTe<inf>2</inf>. We found that Cu<inf>0.5</inf>Ag<inf>0.5</inf>GaTe<inf>2</inf> is both dynamically and elastically stable. Mechanically, the bulk modulus (B) increases, while the shear (G) and Young’s (E) moduli decrease when subjected to Cu doping. The electronic band structure of Cu<inf>0.5</inf>Ag<inf>0.5</inf>GaTe<inf>2</inf> processes the direct band gap (E<inf>g</inf>) of 1.20 eV, which aligns between those of AgGaTe<inf>2</inf> (1.17 eV) and CuGaTe<inf>2</inf> (1.29 eV). The increase in band gap and the trend of mechanical behavior with higher Cu content are attributed to the stronger covalent bonding between Cu-Ag and Cu-Ga pairs compared to Ag-Ag and Ag-Ga pairs. Additionally, the high-pressure phase transitions of this material are explored up to 100 GPa. The first structural phase transition occurs at approximately 6 GPa, from the ambient phase (I4̅) to a tetragonal (P4/mmm) phase. This transition pressure is also intermediate between AgGaTe<inf>2</inf> (4 GPa) and CuGaTe<inf>2</inf> (8 GPa). Further high-pressure phase transitions, including those to the orthorhombic (Pmm2) and monoclinic (Pm) phases, are observed at about 36 and 55 GPa, respectively. These findings demonstrate that Cu<inf>0.5</inf>Ag<inf>0.5</inf>GaTe<inf>2</inf> exhibits consistent trends in the electronic band gap, mechanical properties, and high-pressure phase transitions relative to those of AgGaTe<inf>2</inf> and CuGaTe<inf>2</inf>. This study provides valuable insights into material engineering applications and enhances the understanding of substitutionally doped materials under high-pressure conditions.

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