Gas-sensing Performance Research Articles

Improving Room Temperature Formaldehyde Sensitivity with Samarium-Doped Titanium Dioxide

Abstract Samarium (Sm)-doped titanium dioxide (TiO₂) thin films were synthesized using the spray pyrolysis technique at 400°C, with Sm doping concentrations of 0, 2, 4, and 6 Wt.% to enhance structural, optical, morphological, and gas-sensing properties. The films, deposited on ultrasonically cleaned glass substrates, were characterized using X-ray diffraction , scanning electron microscopy, atomic force microscopy (AFM), and UV-Vis spectroscopy. Structural analysis revealed improved crystallinity and uniform surface morphology with Sm doping, while AFM indicated increased surface roughness, promoting gas adsorption. UV-Vis analysis showed a reduced energy bandgap, enhancing visible light absorption and gas-sensing performance. Gas sensing evaluations demonstrated high sensitivity to formaldehyde, with notable selectivity over ethanol, toluene, and xylene at room conditions. The 6 Wt.% Sm-doped TiO₂ film exhibited the highest response (17.4), with a detection limit of 5 ppm, and fast response (23 s) and recovery (27 s) times. These properties underline the potential of Sm-doped TiO₂ films for efficient room-temperature gas sensors. Their enhanced sensitivity, selectivity, and stability suggest promising applications in environmental monitoring and air quality management, particularly for formaldehyde detection and volatile organic compound discrimination.

A Study on Gas‑sensing Behavior of Reduced Graphene Oxide (rGO) Green Method, Enhansing the Performance of Green-synthesized Reduced Graphene Oxide

This paper presents a comparative study on gas-sensing behavior of reduced graphene oxide (rGO) synthesized by chemical and green synthesis route. GO is synthesized by Hummers method and then reduced employing two reducing agents hydrazine hydrate [represented by (rGO)1] and L-citrulline [represented by (rGO)2]. Synthesized products were then obtained in the form of thin films, and tested for 10 ppm NO2 and CO at operating temperatures of 50, 100, and 150 °C. The green-synthesized reduced graphene oxide (rGO)2 exhibits higher relative response of 254.7% as compared to conventionally synthesized (rGO)1 (93.9%) and GO (22.7%) for 10 ppm NO2 at operating temperature of 150 °C. Furthermore, a switching of conductivity from usual p-type behavior to n-type on exposure of NO2 is observed at all operating temperatures (50, 100, and 150 °C) for GO, (rGO)1, and (rGO)2. The XRD, FTIR, and Raman confirm the oxidation and reduction process. (rGO)2 shows high thermal stability as observed through TGA. FESEM and TEM images show wrinkled sheet structure for GO as well (rGO)1 and (rGO)2. The data observed from the characterization of resultant products have made it possible to explain better reduction of GO through green-reducing agent and enhanced gas-sensing performance of green-synthesized reduced graphene oxide.

Regulation of receptor function in NiCo2O4-SnO2 heterojunction for H2S detection at room temperature

In recent years, the World Health Organization has increasingly emphasized air quality in production environments, leading to heightened societal demands for monitoring of pollutant gases at room temperature. Traditional semiconductor gas-sensitive materials, such as tin oxide (SnO2), have their gas-sensing performance largely limited by their receptor functions, resulting in common issues like low response and poor recovery at room temperature. Spinel-type bimetallic oxides, such as nickel cobaltate (NiCo2O4), offer a unique solution due to their rich adsorption sites on the surface, which provide distinctive receptor functions for detecting toxic gases at room temperature. Herein, NiCo2O4 is synthesized via a one-step hydrothermal method, with a porous spherical cluster structure, and combined with SnO2 to form a heterojunction. The NiCo2O4-SnO2 heterojunction film gas sensor exhibits excellent gas-sensing performance for H2S at room temperature, including high response, short response time, good repeatability, and selectivity. Additionally, the unique receptor functions of the NiCo2O4 were analyzed through first-principles calculations, revealing a semiconductor p-n conversion phenomenon in the presence of H2S gas. The composite also demonstrates a conversion from p-n heterojunction to n-n homojunction during the sensing process, enhancing its gas-sensing performance. This work not only addresses the receptor function limitations of traditional gas-sensitive semiconductor but also provides a feasible approach for controlling carrier types in semiconductors.

Comprehensive overview of detection mechanisms for toxic gases based on surface acoustic wave technology

Identification and detection of toxic/explosive environmental gases are of paramount importance to various sectors such as oil/gas industries, defense, industrial processing, and civilian security. Surface acoustic wave (SAW)-based gas sensors have recently gained significant attention, owing to their desirable sensitivity, fast response/recovery time, wireless capabilities, and reliability. For detecting various types of targeted gases, SAW sensors with different device structures and sensitive materials have been developed with diversified working mechanisms. This paper is focused on overviewing recent advances in working mechanisms and theories of dominant sensitive materials and key mechanisms/principles for targeting various gases in the realm of SAW gas sensors. The basic sensing theories and parameters of SAW gas sensors are briefly discussed, and then the major influencing factors are systematically reviewed, including the effects of various sensitive layer materials, temperature/humidity, and UV illumination on the overall performance of SAW gas sensors. We further highlight the relationships and adsorption/desorption principles between sensing materials and key targeted gases, including NH3, NO2, H2S, explosive gases of H2, and 2,4,6-trinitrotoluene, and organic gases of isopropanol, ethanol, and acetone, as well as others gases of CO, SO2, and HCl. Finally, we discuss key challenges and future outlooks in designing methodologies of sensing materials and enhancing the performance of SAW gas sensors, offering fundamental guidance for developing SAW gas sensors with good sensing performance.

Silver Doped Polypyrrole Nanocomposite-based Gas sensor for Enhanced Ammonia Gas Sensing Performance at Room Temperature

Nanocomposite, which comprise organic and inorganic materials have gained increasing interest in the application for enhanced sensing response to both reducing and oxidation gases. In this study, a nanocomposite is chemical polymerization synthesized by reinforcing Ag nanoparticles with different concentration doped into the matrix of Polypyrrole (PPy). This nanocomposite is used as a sensing platform for ammonia detection with different concentration (ppm). The homogeneous distribution of Ag nanoparticles onto the PPy matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of PPy@Ag matrix is responsible for the outstanding conductivity, compatibility and catalytic power of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were respectively, examined via X-ray diffraction, field emission scanning electron microscopy, Ultraviolet-visible spectroscopy, Thermogravimetric analysis and Fourier transform infrared spectroscopy. The results indicated that sensor based on the PPy@Ag5 (2 gm) nanocomposite showed the highest response toward ammonia as compare to pure PPy at room temperature with a response value is 58 % to 100 ppm. Overall, the obtained findings demonstrated that the PPy@Ag nanocomposite are promising materials for gas sensing applications in environmental monitoring.

Ga-doped ZnO nanoparticles for enhanced CO2 gas sensing applications

Gallium-doped zinc oxide (GZO) has demonstrated significant potential in gas-sensing applications due to its enhanced electrical and chemical properties. This study focuses on the synthesis, characterization, and gas-sensing performance of GZO nanoparticles (NPs), specifically targeting CO₂ detection, which is crucial for environmental monitoring and industrial safety. The GZO samples were synthesized using a sol–gel method, and their crystal structure was determined through X-ray diffraction (XRD), confirming the successful incorporation of gallium into the ZnO lattice. X-ray photoelectron spectroscopy (XPS) was employed to analyze the samples’ elemental composition and chemical state, revealing the presence of Ga in the ZnO matrix and providing insights into the doping effects. Transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDS) was used to confirm the purity and elemental distribution of the synthesized samples, ensuring the homogeneity of the Ga doping. In-situ TEM measurements were also conducted on one of the three samples, with the smallest size. The experiment involved exposing the sample to argon (Ar) as a reference gas and carbon dioxide (CO₂) as the target gas to evaluate the sensor’s response under real-time conditions. The in-situ TEM provided nanoscale observation of changes in the crystal structure parameters, particularly the d-spacing, which exhibited significant alterations exceeding 3.2% when exposed to CO₂ and Ar gases. Furthermore, electron paramagnetic resonance (EPR) and optical joint density of states (OJDS) analyses were performed to examine the presence of paramagnetic defects and to comprehensively understand the electronic structure within the GZO sample, respectively.

Highly Sensitive and Stable In Situ Acetylene Detection in Transformer Oil Using Polyimide-Embedded Carbon Nanotubes.

This study presents an acetylene gas sensor capable of in situ monitoring transformer oils. This sensor utilizes carbon nanotubes (CNTs) embedded in polyimide (PI) synthesized by floating catalyst chemical vapor deposition. Unlike conventional sensors that target hydrocarbon gases dissolved in oil and measure the gas extracted from the oil, the proposed CNT-PI sensor detects gas within the oil in real time. The PI embedding technique effectively anchors and shields the CNT network against fluidic damage, ensuring stable sensing performance over 6 months, even under friction stress caused by oil convection. Decorating CNTs with gold nanoparticles further enhances the sensitivity and response of the sensor. The sensor achieves a high response (10.5% at 30ppm) and fast response/recovery times (28 s/77 s), Furthermore, the sensor demonstrates good response (10.4% at 30ppm) and moderate response/recovery times (444 s/670 s) in an oil medium, which qualifies for industrial applications. Additionally, a CNT-PI-based heater is integrated into the sensor as a multilayer component, maintaining an optimal operating temperature of 90 °C. The CNT-PI sensor demonstrates consistent gas-sensing performance even after 10,000 bending cycles and exhibits superior characteristics, indicating its compatibility with various forms of transformers.

Advanced Nested Coaxial Thin-Film ZnO Nanostructures Synthesized by Atomic Layer Deposition for Improved Sensing Performance

We report a new synthesis method for multiple-walled nested thin-film nanostructures by combining hydrothermal growth methods with atomic layer deposition (ALD) thin-film technology and sacrificial films, thereby increasing the surface-to-volume ratio to improve the sensing performance of novel ZnO gas sensors. Single-crystal ZnO nanorods serve as the core of the nanostructure assembly and were synthesized hydrothermally on fine-grained ALD ZnO seed films. Subsequently, the ZnO core nanotubes were coated with alternating sacrificial coaxial 3D wrap-around ALD Al2O3 films and ALD ZnO films. Basically, the center nanorod was coated with an ALD 3D wrap-around Al2O3 sacrificial layer to realize a nested coaxial ZnO thin-film nanotube. To increase the surface-to-volume ratio of the nested multiple-film nanostructure, both the front and backside of the nested coaxial ZnO films must be exposed by selectively removing the intermittent Al2O3 sacrificial films. The selective removal of the sacrificial films exposes the front and backside of the free-standing ZnO films for interaction with target gases during sensing operation while steadily increasing the surface-to-volume ratio. The sensing response of the novel ZnO gas sensor architecture with nested nanotubes achieved a maximum 150% enhancement at low temperature compared to a conventional ZnO nanorod sensor.

Chemiresistive Gas Sensors Made with PtRu@SnO2 Nanoparticles for Machine Learning-Assisted Discrimination of Multiple Volatile Organic Compounds.

Volatile organic compounds (VOCs) constitute key pollutants in the environment, and exposure to them is associated with negative health impacts. The vigilant monitoring of these pernicious VOCs is imperative for their timely detection and for curtailing the likelihood of both immediate and prolonged exposure, thus safeguarding against the deterioration of environmental quality. In this study, porous PtRu nanoalloys are successfully synthesized via a hydrothermal method and innovatively integrated with SnO2 nanoparticles to significantly enhance the performance of gas sensors. Density functional theory (DFT) calculations substantiated the pivotal role of PtRu nanoalloys in amplifying the sensitivity of SnO2 to acetone. A primary challenge in VOC surveillance is achieving the selectivity required for sensors to accurately identify specific compounds. By employing machine learning algorithms, with a particular emphasis on particle swarm optimization-support vector machine (PSO-SVM), we attained a classification accuracy of 100% in distinguishing between acetone, ethanol, methanol, and formaldehyde. This study demonstrates the potential for creating advanced sensors with selective detection of VOCs.

Hydrogen Gas Sensing Performance of Iron Oxide‐Decorated Carbon Nanotubes: The Influence of Iron Oxide Species and Concentration

In this study, a solvothermal method was used to synthesize a composite of iron oxide nanostructures on carbon nanotubes (CNTs), which was applied as a resistive sensor for hydrogen gas (H2) detection. The nanocomposite was produced with three different iron oxide concentrations (Fe1@CNT, Fe2@CNT, and Fe3@CNT) to investigate the effect of iron species on CNTs and their interaction with hydrogen. Electron microscopy revealed that increasing iron oxide content led to the deterioration of the CNT walls. Raman and FTIR spectra confirmed the predominant presence of α‐Fe2O3 (hematite) on the CNTs, while XPS analysis verified the presence of multiple iron oxides species. High‐resolution XPS of the Fe 2p region indicated the existence of Fe3O4 (magnetite), Fe2O3 (hematite), and FeO (iron(II) oxide) associated with the CNTs. The sample with the lowest iron oxide concentration (Fe1@CNT) showed a 45% sensor response to hydrogen in a dry air atmosphere and the longest recovery time, suggesting a stronger interaction between hydrogen and the nanocomposite. Molecular dynamics simulations and density functional theory calculations further revealed that the presence of iron oxide on the CNT surface significantly altered its electronic properties, particularly by introducing more electronic states near the Fermi level, which enhanced electronic exchange between H2 and the carbon nanotube containing iron oxide.

Hydrothermal synthesis and gas sensing properties of lamellar Nickel Titanate

Synthesizing pure nickel titanate using the hydrothermal method has posed a significant challenge. In this study, single phase lamellar structured nickel titanate were successfully synthesized via the hydrothermal method. X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RAMAN), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) methods were employed to investigated the effects of varying hydrothermal durations and pH values on the sample's structure and gas-sensing performance. Results indicates that hydrothermal duration of 20 h and pH of 13 yielded sample showed single ilmenite phase, and highly sensitive ammonia (NH3) detection capability. At room temperature, the sample exhibited a remarkable response of 17.92 k% to 500 ppm NH3, with a response time of 13.8 s and a recovery time of 2.4 s, and a theoretical detection limit of 3.7 ppm. The exceptional sensing performance can be attributed to lamellar structure that well-exposed surface of the pore, which can absorb more oxygen molecules and provide additional active sites for redox reactions between target gas molecules and adsorbed oxygen. The outcome of this work might provide strategy for the design of novel sensing materials.

Monolayer Amphiphiles Hydrophobicize MoS2-Mediated Real-Time Water Removal for Efficient Waterproof Hydrogen Detection.

Ensuring water-fouling-free operation of semiconductor-based gas sensors is essential to maintaining their accuracy, reliability, and stability across diverse applications. Despite the use of hydrophobic strategies to prevent external water intrusion, addressing in situ-produced water transport during H2 detection remains a challenge. Herein, we construct a novel waterproof H2 sensor by integrating single-atom Ru(III) self-assembly with monolayer amphiphiles embedded in MoS2. The unique monolayer structure enables the sensor to detect H2 in the presence of water, as well as facilitate the self-transport of in situ-generated water from the H2-O2 reaction during H2 detection. Molecular dynamics simulations reveal that monolayer amphiphiles exhibit a higher water diffusion coefficient than multilayer amphiphiles, making them more advantageous for removing in situ-produced water. Deployable on mobile platforms, it enables wireless H2cat detection for up to 6 months, without the introduction of protective membranes against dust and water ingress. This work not only enhances the performance of H2 detection but also introduces a new concept for the advancement of stable water-sensitive sensors.

Organic‐Based Chemiresistive Sensors for Detection of Water‐Soluble Gases: Strategies and Roadmap for Enhancing Sensing Performance

AbstractTraditional organic‐based chemiresistive sensors have been a key area of research due to their portability, low power consumption, low cost, turnability, and possibility for miniaturization. However, their real‐world applications have remained restricted by their low selectivity, low sensitivity, and low stability under demanding conditions, such as extreme temperature, humidity, and pH. As such, this review aims to lay the foundation for enhancing the performance of these gas sensors via chemical and physical modifications. To this end, an insight into the building blocks of chemiresistive gas sensors and the attributes of the main four gases (ammonia, carbon dioxide, hydrogen sulfide, and nitrogen dioxide) under aqueous conditions are provided. Such features ultimately determine the enhancement strategy that is best suited to improve the chemiresistive gas sensors performance. Furthermore, this article provides an outlook into the current bottleneck in sensor development and its translation from lab to end‐consumer use. Overall, this review aims to serve as a roadmap for developing next‐generation, high performing chemiresistive gas sensors.

Emerging NO2 gas sensing on substitutionally doped Fe on NiWO4 SCES insulators.

In this study, we demonstrate the emergence of NO2 gas sensing capabilities in the typically non-active NiWO4, a strongly correlated electron system (SCES), by introducing substitutional Fe at the Ni site. NiWO4 typically exhibits strong Coulombic repulsion between Ni atoms, resulting in a large band gap of over 3.0eV and insulating behavior. This correlated behavior is clearly reflected in the significant increase of band gap when considering the Hubbard U correction for the cations, bringing the theoretical value closer to the observed value. The single-phase Fe0.5Ni0.5WO4 displays a notable shift in the [NiO6] symmetric vibration mode and an increase in magnetization. Additionally, theoretical calculations confirm the preservation of the wide band gap, with the Fe and O levels generated within the band gap. These findings indicate that Fe located in the Ni sites modulate Coulombic repulsion in NiWO4 SCES insulators. Unlike the poor gas-sensing performance of intrinsic NiWO4, Fe0.5Ni0.5WO4 exhibits a significant NO2 response (Rg/Ra) of 11 at 200°C than other gases and a limit of detection (LOD) of 46.4ppb. This study provides a pathway for realizing gas-sensing performance in strongly correlated electron insulators with large band gaps through the introduction of dopant levels at the cation sites.

Bottom-up designing nanostructured oxide libraries under a lab-on-chip paradigm towards a low-cost highly-selective E-nose

BackgroundThe multisensor concept has been developed as a powerful alternative to well-known gas-analytical instrumentation for applications where a fast but accurate and reliable assessment of the environment is required. The concept follows a biology-inspired approach where the selectivity towards various gases/odors is attained via pattern recognition of multisensory signal vectors. Herein, we discuss how to design a selective multisensor library based on various metal oxide nanostructures like a lab-on-chip using a simple but efficient bottom-up growth of materials over the multi-electrode chip under robust dc electrochemical protocols. ResultsIn addition to a conventional growth of oxide layers over the metal electrodes, we show that the fine nanowall-like oxide structures appear as a quasi-matrixed percolation film over the SiO2 substrate surface in the inter-electrode gaps to constitute a chemiresistive film. We have tested two directions while applying the technique to grow Co, Ni, Mn, and Zn oxides to develop on-chip sensor arrays of, (i) monoxide type employing the oxide films with gradual change of growth time, and (ii) multi-oxide type based on the four oxides. The materials were thoroughly characterized by electron microscopy, X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy/mapping to prove the composition and structure. Among tested oxides, ZnO readily appears not only at the electric potential-targeted chip zone but also in other areas to dope the films for yielding heterojunctions with other oxides that enhances a variability of functional properties in the on-chip sensor array. The gas-sensing performance of the chips has been tested versus various chemically akin alcohol vapors at the sub- and low ppm range of concentrations in a mixture with air. SignificanceWe show that the grown oxide nanostructures exhibit a high-sensitive chemiresistive signal which allows one to build a multisensor vector signal, selective to the kind of alcohols, even at sub-ppm concentrations. Moreover, the multi-oxide library yields options for a superior selectivity under LDA metrics than the gradient-grown mono-oxide one due to the versatility of materials while the low-cost growth protocols remain to be the same in both cases. The delivered method to produce multisensor arrays allows one producing low-cost but efficient electronic nose units for numerous applications.

Highly-enhanced gas-sensing performance of metal-doped In2O3 microtubes from acceptor doping and double surface adsorption

The different valent metal-doping is a feasible and convenient way to adjust the microstructures and electron concentration of In2O3 gas sensors. In this paper, the different valence metals (Zn2+, Sb3+, Zr4+ and Nb5+) are doped into MIL-68 (In) metal–organic frameworks (MOFs) by solvothermal method, and then In2O3 and metal-doped In2O3 microtubes are obtained by pyrolysis MIL-68 MOFs. All samples exhibit the similar microtubular structures, indicating oxygen adsorption on both inner and outer surface. The average grain size of metal-doped In2O3 microtubes decreases a little while the specific surface area increases greatly. Metal-doping greatly affects the formaldehyde gas-sensing performance, and Zn2+-doped In2O3 sensor presents the highest response value (188.56), shortest response/recovery times and excellent selectivity to formaldehyde gas at 210 ℃. Compared the microstructural and gas-sensing parameters of In2O3 sensor, the specific surface area and oxygen vacancies of metal-doped In2O3 sensors enhance the surface O-. Moreover, acceptor Zn2+-doping directly extracts electrons from conduction band of Zn2+-doped In2O3 sensor, which greatly increases the resistance in air and the thickness of electron deletion layer for Zn2+-doped In2O3 sensor.

Eu3+-doped MoO3 one-dimensional ice-lolly-like nanorods: Achieving red down-conversion luminescence and significantly enhancing triethylamine gas-sensing performance

A novel MoO3:x%Eu3+ one-dimensional (1D) ice-lolly-like nanorods with bifunctionality of luminescence and gas sensitivity are successfully prepared via electrostatic spinning and oxidative calcination. Among them, MoO3:x%Eu3+ 1D ice-lolly-like nanorods exhibit exceptional luminescence properties, with an emission peak at 616 nm when excited at a wavelength of 274 nm. The MoO3:x%Eu3+ 1D ice-lolly-like nanorods possess excellent gas-sensitizing properties to triethylamine (TEA) when they are fabricated to be gas sensors. The response value of MoO3:1%Eu3+ 1D ice-lolly-like nanorods gas sensor to 100 ppm TEA at 290 °C is 127.9, which is 11.5 times higher than that of the pure MoO3 (11.1) gas sensor. Furthermore, the MoO3:1%Eu3+ 1D ice-lolly-like nanorods gas sensor exhibits an ultra-fast response/recovery time (1 s/14 s). In addition, doped Eu3+ at the MoO3 interface leads to enhanced electronic and catalytic properties, thereby leading to a significant improvement in the gas-sensing performance of MoO3. More importantly, the doping of Eu3+ can simultaneously achieve excellent red down-conversion luminescence performance and enhance the gas-sensitive properties of MoO3. This can be attributed to the fact that Eu3+ serves as both a luminescent center and a sensitizer for MoO3, achieving the effect of killing two birds with one stone. The possible mechanisms of photoluminescence and gas sensing are also proposed. This design idea introduces an innovative approach for rapidly detecting damage to the sensing coating of gas sensors, achieved by illuminating the sensing material with excitation light. This work offers insights for constructing novel bifunctional composites with luminescence and gas sensing, broadening the application of gas sensors.

High Sensing Performance of n-Butanol Gas Sensor Based on Mesoporous Cu-Doped α-Fe₂O₃ Nanoparticle Materials

High Sensing Performance of n-Butanol Gas Sensor Based on Mesoporous Cu-Doped α-Fe₂O₃ Nanoparticle Materials

Development of High-Performance Ethanol Gas Sensors Based on La2O3 Nanoparticles-Embedded Porous SnO2 Nanofibers.

Porous pure SnO2 nanofibers (NFs) and La2O3 nanoparticles (NPs)-embedded porous SnO2 NFs were successfully synthesized via electrospinning followed by calcination. These materials were systematically evaluated as gas-sensing elements in metal-oxide-semiconductor (MOS) sensors. The La2O3 NPs embedded in porous SnO2 NFs demonstrated superior gas-sensing performance compared to pure SnO2 NFs. Specifically, the incorporation of La2O3 resulted in a 12-fold enhancement in gas-sensing response towards ethanol, significantly improving both sensitivity and selectivity by tuning the carrier concentration and modifying oxygen deficiencies and chemisorbed oxygen levels. Thus, La2O3 NPs embedded in SnO2 NFs present a promising strategy for the development of high-performance ethanol gas sensors.

Enhanced NO2 Gas Sensing in Nanocrystalline MoS2 via Swift Heavy Ion Irradiation: An Experimental and DFT Study.

Nanostructured transition metal dichalcogenides (TMDs) like MoS2 hold promise for gas sensing applications due to their exceptional properties. However, limitations exist in maximizing sensor performance, such as limited active sites for gas interaction and sluggish response/recovery times. This study explores swift heavy ion (SHI) irradiation as a strategy to address these challenges in MoS2-based NO2 gas sensors. MoS2 nanoflakes were fabricated and subsequently irradiated with 120 MeV silver (Ag) ions to induce structural and morphological modifications. Characterization techniques confirmed the formation of Mo and S vacancies within the MoS2 lattice due to irradiation. Significantly, SHI irradiation resulted in a remarkable enhancement of approximately 3 times improvement in sensing response compared to pristine MoS2 sensors. Additionally, the irradiated sensors exhibit substantial improvements in both response and recovery times for NO2 detection. SHI irradiation resulted in the formation of self-affine nanostructures and increased grain fragmentation as fluence rises. This enhanced surface area is hypothesized to promote gas-sensor response. To gain deeper insights into the underlying mechanism, first-principles calculations were employed. These calculations suggest that electron transfer occurs from the MoS2 surface to the NO2 molecule during interaction. Furthermore, the irradiation-induced vacancies facilitate stronger NO2 adsorption on the MoS2 surface compared to the pristine sample. This work demonstrates the effectiveness of SHI irradiation in engineering defects within MoS2 nanoflakes, leading to significantly improved NO2 gas-sensing performance. This approach offers a promising avenue for developing next-generation TMD-based gas sensors with enhanced sensitivity, response times, and stability.