Liquefied petroleum gas (LPG) is widely used as a clean fuel but accidental leakage poses serious safety hazards, demanding rapid and selective detection at room temperature. This study reports a novel ZnO@MoTe2 heterostructures synthesized via hydrothermal route for ultrafast room-temperature LPG sensing. Comprehensive structural analysis included the following: Rietveld refinement of Powder X‐ray diffraction (PXRD) confirms the phase purity (2H-MoTe2 and wurtzite ZnO) with crystallite sizes of 34.65–45.18 nm, Raman spectroscopy further verifies the phase formation through characteristic vibrational modes of MoTe2 and ZnO, Fourier transform infrared spectroscopy (FTIR) identifies the characteristic Mo-Te (602, 735 cm−1) and Zn–O (548 cm−1) vibrations, Field emission scanning electron microscopy (FE-SEM) confirms the successful interfacial integration, and Energy dispersive X-ray spectroscopy (EDS) verifies the presence of Zn, O, Mo, and Te elements in the synthesis of ZnO@MoTe2 heterostructure. HRTEM analysis revealed distinct lattice fringes of 2H-MoTe2 (d011 ≈ 0.32 nm) and ZnO (d100 ≈ 0.28 nm), within a single heterostructure. UPS analysis demonstrated modulation of the surface electronic structure, work function, and valence band alignment after heterostructure formation, indicating strong interfacial electronic coupling. The fabricated sensing film demonstrated exceptional analytical performance including response of 8.18 toward 2.0 vol% of LPG, ultrafast response/recovery time of 2.57/3.07 s at 0.5 vol% LPG, high sensitivity of 4.244 response units/vol% (R2 = 0.99), excellent reproducibility (98.2 ± 1.8% over 5 cycles), and superior selectivity (K = 1.95–2.29) against CO2, ethanol, and acetone. Density functional theory (DFT) calculations revealed a significant modulation of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap at the ZnO@MoTe2 heterointerface, indicating interfacial charge transfer and depletion-layer variation upon gas adsorption. The adsorption energy confirmed the energetically favorable adsorption of LPG molecules on the heterostructure surface. Electrostatic surface potential (ESP) analysis demonstrated significant charge redistribution across the interface. The theoretical findings are consistent with the experimentally observed sensing response. Overall, the results demonstrate that ZnO@MoTe2 heterostructures provide an effective and energy-efficient platform for practical low-power gas detection applications.

Chemiresistive LPG sensor based on novel ZnO@MoTe₂ heterostructure: a combined density functional theory and experimental study

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发表日期：

2026年6月18日

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Ankit Singh,
Avdhesh Kumar,
Alka Rani,
Uma Shankar,
Navin Chaurasiya,
Bal Chandra Yadav,
Manish Pratap Singh

摘要

Liquefied petroleum gas (LPG) is widely used as a clean fuel but accidental leakage poses serious safety hazards, demanding rapid and selective detection at room temperature. This study reports a novel ZnO@MoTe₂ heterostructures synthesized via hydrothermal route for ultrafast room-temperature LPG sensing. Comprehensive structural analysis included the following: Rietveld refinement of Powder X‐ray diffraction (PXRD) confirms the phase purity (2H-MoTe₂ and wurtzite ZnO) with crystallite sizes of 34.65–45.18 nm, Raman spectroscopy further verifies the phase formation through characteristic vibrational modes of MoTe₂ and ZnO, Fourier transform infrared spectroscopy (FTIR) identifies the characteristic Mo-Te (602, 735 cm⁻¹) and Zn–O (548 cm⁻¹) vibrations, Field emission scanning electron microscopy (FE-SEM) confirms the successful interfacial integration, and Energy dispersive X-ray spectroscopy (EDS) verifies the presence of Zn, O, Mo, and Te elements in the synthesis of ZnO@MoTe₂ heterostructure. HRTEM analysis revealed distinct lattice fringes of 2H-MoTe₂ (d₀₁₁ ≈ 0.32 nm) and ZnO (d₁₀₀ ≈ 0.28 nm), within a single heterostructure. UPS analysis demonstrated modulation of the surface electronic structure, work function, and valence band alignment after heterostructure formation, indicating strong interfacial electronic coupling. The fabricated sensing film demonstrated exceptional analytical performance including response of 8.18 toward 2.0 vol% of LPG, ultrafast response/recovery time of 2.57/3.07 s at 0.5 vol% LPG, high sensitivity of 4.244 response units/vol% (R² = 0.99), excellent reproducibility (98.2 ± 1.8% over 5 cycles), and superior selectivity (K = 1.95–2.29) against CO₂, ethanol, and acetone. Density functional theory (DFT) calculations revealed a significant modulation of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap at the ZnO@MoTe₂ heterointerface, indicating interfacial charge transfer and depletion-layer variation upon gas adsorption. The adsorption energy confirmed the energetically favorable adsorption of LPG molecules on the heterostructure surface. Electrostatic surface potential (ESP) analysis demonstrated significant charge redistribution across the interface. The theoretical findings are consistent with the experimentally observed sensing response. Overall, the results demonstrate that ZnO@MoTe₂ heterostructures provide an effective and energy-efficient platform for practical low-power gas detection applications.

Chemiresistive LPG sensor based on novel ZnO@MoTe2 heterostructure: a combined density functional theory and experimental study

摘要

Chemiresistive LPG sensor based on novel ZnO@MoTe₂ heterostructure: a combined density functional theory and experimental study