Gas-sensing Performance Research Articles

3D ZnO/ZIF‐8 Hierarchical Nanostructure for Sensitive and Selective NO2Sensing at Room Temperature

Gas sensors based on semiconductor metal oxides (SMOs) have gained widespread attention for Internet of Things applications; however, high operating temperatures and low gas selectivity limit their applications. Recently, metal–organic frameworks (MOFs) have demonstrated potential in enhancing gas selectivity through the physical filtration of gas molecules based on their kinetic diameters. However, their application has been predominantly limited to simplistic nanostructured sensors. These sensors exhibit inherently inferior gas sensor performance compared to three‐dimensional nanostructure gas sensors. In this study, a highly periodic, 3D hierarchical ZnO/ZIF‐8 nanostructure is fabricated for photoactivated gas sensing at room temperature. Under UV illumination, the gas sensor exhibited a 17‐fold enhancement in gas response toward 0.1 ppm NO2compared to pristine ZnO. In addition, the ZIF‐8 coating selectively increased the NO2gas response compared to ethanol, acetone, and toluene gases, thereby improving the gas selectivity. The gas response improvement by the ZIF‐8 layer coating, which has not been achieved by previous studies, is based on enhanced photoactivation by the solid interaction between ZIF‐8 and ZnO. These results provide a systematic background for controlling the layer thickness of SMO‐MOF nanostructures and the catalytic role of MOF in photoactivated gas sensing.

Growth and Characterization of Sputtered InAlN Nanorods on Sapphire Substrates for Acetone Gas Sensing.

The demand for highly sensitive and selective gas sensors has been steadily increasing, driven by applications in various fields such as environmental monitoring, healthcare, and industrial safety. In this context, ternary alloy indium aluminum nitride (InAlN) semiconductors have emerged as a promising material for gas sensing due to their unique properties and tunable material characteristics. This work focuses on the fabrication and characterization of InAlN nanorods grown on sapphire substrates using an ultra-high vacuum magnetron sputter epitaxy with precise control over indium composition and explores their potential for acetone-gas-sensing applications. Various characterization techniques, including XRD, SEM, and TEM, demonstrate the structural and morphological insights of InAlN nanorods, making them suitable for gas-sensing applications. To evaluate the gas-sensing performance of the InAlN nanorods, acetone was chosen as a target analyte due to its relevance in medical diagnostics and industrial processes. The results reveal that the InAlN nanorods exhibit a remarkable sensor response of 2.33% at 600 ppm acetone gas concentration at an operating temperature of 350 °C, with a rapid response time of 18 s. Their high sensor response and rapid response make InAlN a viable candidate for use in medical diagnostics, industrial safety, and environmental monitoring.

MoS2/MoO3 heterojunctions enabled by surface oxidization of MoS2 nanosheets for high-performance room-temperature NO2 gas sensing

Transition-metal dichalcogenides (TMDs) have emerged as ideal candidates for room-temperature gas sensing due to their remarkable semiconductor properties. However, bare TMDs typically exhibit drawbacks such as low sensitivity, slow response, and low recovery speeds, which limit their applicability. In comparison to single materials, enhancing the sensing performance of the material can be achieved through the realization of heterostructures. Therefore, the key to improving the performance of metal-sulfide gas sensors lies in the controlled construction of unique heterostructures. In this work, surface heterostructures composed of molybdenum disulfide (MoS2) nanoflowers loaded with molybdenum trioxide (MoO3) enabled are realized through the surface oxidization of MoS2 nanosheets for high-performance room-temperature detection of NO2 gas. The heterostructures were easily constructed by oxidizing flower-like MoS2 using a hydrogen peroxide aqueous solution. The gas sensor based on the MoS2/MoO3 heterojunction exhibits a response of 18.9 % to 1 ppm NO2, which is nine times higher than that of the MoS2 sensor (2.1 %). Furthermore, even at a NO2 concentration as low as 50 ppb, the sensor response can reach 6.9 %. The sensor displays good repeatability and excellent selectivity. The enhanced gas-sensing performance of the MoS2/MoO3 heterostructure may result from the unique structure of MoS2 and the p-n heterojunction formed at the interfaces. The proposed design strategy and the surface heterostructure constructed in this work can provide guidance for the development of high-performance gas-sensitive materials and devices.

An Investigation on the Acetone and Ethanol Vapor-Sensing Behavior of Sol-Gel Electrospun ZnO Nanofibers Using an Indigenous Setup.

The calibration is essential for accuracy, repeatability, and continuous trouble-free operation of gas sensors with safety. Most gas sensors are fabricated using metal oxide nanomaterials in different structures such as films, coating, or nanofibers. Therefore, a device in the sensor manufacturing industry is necessary to test, calibrate, and optimize metal oxide structures. In this point of view, a simple device is developed to test and estimate the sensing response, response time, and recovery time of nanostructures. The sol-gel method was used to produce nanofibers through electrospinning. An average fiber diameter of 245 nm was obtained after pyrolysis at 600 °C. The structure and composition of ZnO nanofibers are confirmed by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller. The trials were taken using ZnO nanofibers in the presence of acetone and ethanol vapor, and the results were reported. High response (31.74), rapid response (40 s), and recovery (30 s) times have been achieved for ethanol gas to 50 ppm concentration test gas at an optimal temperature of 260 °C. The results obtained from the trials are compared with the literature results, which are in line with the values presented by the various researchers. Due to the low cost, easy maintenance, and accuracy, this device is recommended in metal oxide sensor development industries and laboratories.

High-performance flexible organic gas sensor via alkyl side chain engineering of polyalkylthiophene

Poly(3-alkylthiophene) (P3AT) is a representative p-type organic semiconductor with a distinctive molecular structure that incorporates a π-electron system, promoting charge carrier mobility and providing exceptional electrical conductivity. The alkyl side chain linked to the π-electron backbone was found to have a significant effect on charge carrier transport and mechanical properties. This study presents a comprehensive comparison of the gas-sensing performances of various gases (NO2, SO2, and CO2) and the mechanical properties of gas sensors fabricated from P3AT with alkyl chain lengths of 6, 8, 10, and 12 (P3HT, P3OT, P3DT, and P3DDT). Our investigations revealed that as the alkyl side chain length increased, the gas sensor performance significantly improved owing to the increase in free volume, concurrently promoting improved flexibility. The P3DDT sensor exhibited a sensitivity approximately twice that of the P3HT sensor, along with superior mechanical flexibility owing to its free volume.

Effect of kinetic properties of zeolites on the gas-sensing performance of zeolite-covered SnO2 sensors

ABSTRACT Zeolite additional layers coating on metal oxide surfaces to improve the selectivity and response values of the sensors are effective and widely used. The specific adsorption and diffusion of gas molecules in the zeolite are recognised to play an important role in gas sensing improvement. In this work, the adsorption and diffusion behaviours of formaldehyde and acetone in H-Y and H-A zeolites were calculated by Monte Carlo and molecular dynamics simulations. The loading of acetone is greater than formaldehyde in these two kinds of zeolites under the same temperature and pressure, and the water load is lower. The simulation results show that the effects of the nature of the guest molecule and steric hindrance of the diffusing molecule on diffusivity are significant. The diffusivity in H-A zeolite decreases by several orders of magnitude than that in H-Y zeolite However, in H-A zeolite, the internal diffusion dominates, and only the smaller diameter formaldehyde can diffuse between the pores, which is beneficial to improving the sensing properties of formaldehyde. In addition, in the competition diffusion with water molecules, formaldehyde dominates than acetone. The H-Y/SnO2 and H-A/SnO2 sensors were prepared to verify the reliability of the molecular simulations. Research highlights The adsorption and diffusion behaviour of formaldehyde and acetone in H-Y and H-A zeolites were investigated using molecular simulation. Molecular diameter mainly influences the kinetic behaviour. The sensitisation mechanism of H-Y/SnO2 sensor to acetone and H-A/SnO2 sensor to formaldehyde was proved. Focuses on the relationship between gas-sensing the performance of zeolite-covered SnO2 sensors and the adsorption.

MIL-68 derived In2O3 microtubes and Co3O4/In2O3 heterostructures for high sensitive formaldehyde gas sensors

The gas sensors with high response and selectivity are important for detecting and monitoring formaldehyde gas in real-time. In this paper, In2O3 microtubes are derived from metal organic framework named MIL-68 and Co3O4 nanoparticles are successfully loaded on the surface of In2O3 microtubes to form Co3O4/In2O3 heterostructures via one-step hydrothermal and calcination methods. The crystal structure, surface morphology and components of all samples are characterized and the formaldehyde gas-sensing performance is investigated in detail. All results indicates that Co3O4 nanoparticles greatly improve the formaldehyde gas-sensing performance of Co3O4/In2O3 heterostructures. Specifically, Co3O4/In2O3 (9 wt%) sensor exhibits a higher response (1215.47) to 10 ppm formaldehyde gas, which is about 10.16 times than that of pristine In2O3 sensor. Furthermore, Co3O4/In2O3 (9 wt%) sensor possesses a shorter recovery time (81 s), lower working temperature (190 °C), excellent selectivity, superior linear properties. As a result, Co3O4/In2O3 sensors exhibit excellent gas-sensing properties because of the synergistic effect of the catalytic activity of Co3O4 nanoparticles, the formation of p-n heterojunction and the increasing surface oxygen.

Enhanced hydrogen gas sensing through the utilization of a hybrid nanostructure combining ZnO nanotubes and HiPIMS Cu3N thin film

Hydrogen (H2), a renewable energy source, has emerged as a promising and clean fuel alternative to conventional fossil fuels. It has garnered significant attention from researchers due to its wide-ranging applications in promoting sustainable growth. However, accurately detecting atmospheric H2 levels becomes crucial due to its flammability. This study introduces a room temperature-based hydrogen gas sensor composed of vertically hydrothermally grown ZnO nanotubes (ZNTs) with or without the incorporation of a Cu3N thin film, creating a hybrid nanostructure. The ZNTs and ZNTs/Cu3N nanohybrid samples were fabricated with multi-finger configurations of Palladium (Pd) interdigitated electrodes. The ZNTs/Cu3N nanohybrid exhibited exceptional sensing capabilities compared to those of the as-prepared ZNTs. It was tested with varying concentrations of H2, ranging from 10 to 500 ppm, at room temperature. The ZNTs/Cu3N nanohybrid's superior performance is due to its larger surface area, enabling improved gas ion adsorption, increased oxygen vacancies, and more surface-active sites compared to ZNTs alone. The Cu3N layer beneath the ZNTs greatly impacts the gas sensor's performance by lowering the ZNTs/Cu3N nanohybrid's band gap (1.85 eV), enhancing its H2 detection capabilities. The ZNTs/Cu3N nanohybrid demonstrates great potential for future gas sensor applications, offering valuable insights for advanced sensing technology development.

Fabrication of YSZ ceramic thin films with sol-gel method for mixed potential-type zirconia-based NO2 sensor

In this work, yttria-stabilized zirconia (YSZ) thin films were prepared by sol-gel and spin-coating methods, which are simple and inexpensive, with good film quality and excellent electrical conductivity. Using this film, a YSZ film mixed-potential type NO2 gas sensor with NiO as the sensitive electrode material was fabricated. The films had the best dielectric properties when spin-coated four times, and the sensors had the highest response (48 mV–100 ppm NO2) as well as the best sensitivity (14.8 mV/decade for 5–20 ppm NO2 and 42 mV/decade for 20–500 ppm NO2). The YSZ thin-film gas sensor operates at a lower temperature, with an optimum operating temperature of 550 °C, and the power consumption of the sensor has been reduced by approximately 46 % or more compared to conventional bulk YSZ NO2 gas sensors. This provides a very effective direction for the low-power design of high-temperature devices such as the YSZ gas sensor. In addition, thin-film devices are more conducive to integrating sensors into microelectronic circuits, greatly improving the application scenarios for such devices. This sensor has excellent repeatability, very good selectivity, and outstanding long-term stability over 30 days of continuous measurement. In conclusion, based on the excellent sensing performance and low power consumption of the YSZ thin-film gas sensor, the sensor has a promising future for in-situ monitoring of NOx.

Highly Selective NO2 Sensors Based on Electrolytically Exfoliated Graphene/Flame-made WO3 Composite Films

Gas sensors based on flame-synthesized WO3 nanoparticles loaded with 0.2-5 wt% electrochemically exfoliated graphene were evaluated for NO2 detection at ppb levels. The characterizations by X-Ray diffraction, nitrogen adsorption, electron microscopy and Raman spectrometry verified that multi-layer graphene sheets were well dispersed within spheroidal WO3 nanoparticles. Sensing layers fabricated with different graphene loading levels were tested towards 50-5000 ppb NO2 with varying operating temperatures from 100 to 350 °C in dry air. From the test results, the graphene-loaded WO3 nanoparticles with the optimal graphene content of 2 wt% exhibited the highest sensor response of ~ 5061 to 5000 ppb NO2 at the optimum working temperature of 150 °C. Furthermore, the sensor based on graphene/WO3 composites displayed high NO2 selectivity against various environmental gases and volatile organic compounds at 150 °C. The mechanistic roles of graphene on NO2 gas-sensing performances were described based on reactive ohmic M-S heterointerfaces. Therefore, the combination of electrochemically exfoliated graphene and flame-made WO3 nanoparticles could be an attractive mean to achieve highly sensitive and selective NO2 sensors.

A CNN-assisted mid-infrared high-sensitivity exhaled ammonia sensor based on cavity ring-down spectroscopy

The cavity ring-down spectroscopy (CRDS) is becoming increasingly important in sensitive gas detection for atmospheric pollutant detection, greenhouse gas monitoring, human respiratory gas analysis, and measurement of specific gases in industrial processes. However, the accuracy and sensitivity of CRDS are greatly limited by noise and ring-down time extraction algorithms. To solve this problem, a CNN-assisted high-sensitivity exhaled ammonia sensor based on cavity ring-down spectroscopy was developed in this paper, which is the first time to introduce the convolutional neural network to cavity ring-down spectroscopy. A CNN filter and a neural network-based ring-down time extraction algorithm trained by two different datasets were applied to the sensor, solving the shortcomings of the traditional CRDS. Among several filters, the CNN filter achieves the best performance and the SNR is improved by 3.4 times. Compared to traditional nonlinear fitting algorithm, a sensitivity enhancement factor of 3.48 was obtained and a sub-ppb detection limit can be achieved by using Allan deviation analysis. The experimental results prove the feasibility of deep learning for improving the performance of cavity ring-down spectroscopy gas sensor.

Thickness-Dependent Room-Temperature Optoelectronic Gas Sensing Performances of 2D Nonlayered Indium Oxide Crystals from a Liquid Metal Printing Process.

Due to excellent gas sensing performances, such as high responsivity, good selectivity, and long-term stability, two-dimensional (2D) nonlayered metal oxide semiconductors have attracted wide attention. However, their thickness-dependent gas sensing behaviors are rarely investigated, which is critical in the development of practical 2D sensors. In this work, 2D In2O3 crystals with a range of thicknesses are realized by extracting the self-limited oxide layer from the liquid indium droplets in a controlled environment. A strong thickness-dependent optoelectronic NO2 sensing behavior at room temperature is observed. While full reversibility and excellent selectivity toward NO2 are shown despite the thicknesses of 2D In2O3, the 1.9 nm thick In2O3 exhibits a maximum response amplitude (ΔI/Ig = 1300) for 10 ppm of NO2 at room temperature with 365 nm light irradiation, which is about 18, 58, and 810 times larger than those of its 3.1 nm thick, 4.5 nm thick, and 6.2 nm thick counterparts, respectively. The shortest response and recovery times (i.e., 40 s/48 s) are demonstrated for the 1.88 nm thick In2O3 as well. We correlate such a phenomenon with the change in the In2O3 band structure, which is influenced by the thickness of 2D crystals. This work provides in-depth knowledge of the thickness-dependent gas-sensing performances of emerging 2D nonlayered metal oxide crystals, as well as the opportunities to develop next-generation high-performing room-temperature gas sensors.

Polyaniline Composites Containing Eco-Friendly Biomass Carbon from Agricultural-Waste Coconut Husk for Enhancing Gas Sensor Performance in Hydrogen Sulfide Detection.

Hydrogen sulfide, a colorless, flammable gas with a distinct rotten egg odor, poses severe health risks in industrial settings. Sensing hydrogen sulfide is crucial for safeguarding worker safety and preventing potential accidents. This study investigated the gas-sensing performance of an electroactive polymer (i.e., polyaniline, PANI) and its composites with active carbon (AC) (i.e., PANI-AC1 and PANI-AC3) toward H2S at room temperature. PANI-AC composites-coated IDE gas sensors were fabricated and their capability of detecting H2S at concentrations ranging from 1 ppm to 30 ppm was tested. The superior gas-sensing performance of the PANI-AC composites can be attributed to the increased surface area of the materials, which provided increased active sites for doping processes and enhanced the sensing capability of the composites. Specifically, the incorporation of AC in the PANI matrix resulted in a substantial improvement in the doping process, which led to stronger gas-sensing responses with higher repeatability and higher stability toward H2S compared to the neat PANI-coated IDE sensor. Furthermore, the as-prepared IDE gas sensor exhibited the best sensing response toward H2S at 60% RH. The use of agricultural-waste coconut husk for the synthesis of these high-performance gas-sensing materials promotes sustainable and eco-friendly practices while improving the detection and monitoring of H2S gas in industrial settings.

Microwave-assisted efficient synthesis of ZnO nanospheres for low temperature NO2 gas sensor

The development of high-performance nitrogen dioxide gas sensors is indispensable and critical for environmental monitoring and medical fields. Different nanostructural ZnO were efficiently synthesized via a microwave-assisted gas-liquid interface method and the gas sensing performance of ZnO-based gas sensors with different morphologies was comparatively investigated. The results show that the ZnO-3 sensor (microwave reaction temperature is 180 ℃) has the best sensing performance to NO2 at lower operating temperature (120 ℃). It exhibits a high response (Rg/Ra = 397), short response/recovery time (21 s/30 s), and good selectivity to 100 ppm NO2. Moreover, the ZnO-3 sensor exhibits remarkably high response (185 to 100 ppm NO2) even at 25 ℃. In addition, the ZnO sensor can maintain good stability and repeatability in long-term cycling tests to 5 ppm NO2. Evidently, this research offers a reference value for the efficient synthesis of ZnO nanomaterials and real-time detection of nitrogen dioxide emissions.

Preparation and Gas-Sensing Properties of Two-Dimensional Molybdenum Disulfide/One-Dimensional Copper Phthalocyanine Heterojunction

Although 2D MoS2 alone shows excellent gas-sensing performance, it is prone to stacking when used as the sensitive layer, resulting in insufficient contact with the target gas and lower sensitivity. To solve this, a 2D-MoS2/1D-CuPc heterojunction was prepared with different weight ratios of MoS2 nanosheets to CuPc micro-nanowires, and its room-temperature gas-sensing properties were studied. The response of the 2D-MoS2/1D-CuPc heterojunction to a target gas was related to the weight ratio of MoS2 to CuPc. When the weight ratio of MoS2 to CuPc was 20:7 (7-CM), the gas sensitivity of MoS2/CuPc composites was the best. Compared with the pure MoS2 sensor, the responses of 7-CM to 1000 ppm formaldehyde (CH2O), acetone (C3H6O), ethanol (C2H6O), and 98% RH increased by 122.7, 734.6, 1639.8, and 440.5, respectively. The response of the heterojunction toward C2H6O was twice that of C3H6O and 13 times that of CH2O. In addition, the response time of all sensors was less than 60 s, and the recovery time was less than 10 s. These results provide an experimental reference for the development of high-performance MoS2-based gas sensors.

Synthesis of Pr doped In2O3 nanoparticles and their enhanced ethanol gas-sensing performance

Rare earth doping was an effective method to upgrade the gas-sensing performance of sensors based on oxide semiconductors. In this paper, Pr was successfully doped into In2O3 nanomaterials with a facile co-precipitation approach through a hydrothermal strategy. The as-obtained series of Pr doped In2O3 nanocomposites were analyzed by some technical characterization. The gas-sensing tests were performed by using series of Pr/In2O3 nanocomposites as sensitive materials. The results illustrated that the doping of Pr not only reduced the particle size of Pr/In2O3 nanocomposites but also produced more active oxygen on the surface of In2O3, thus, the responses of Pr/In2O3-based sensors towards ethanol gas (112.40–50 ppm) were enhanced. A possible mechanism for the improved gas-sensing property of Pr decorated In2O3 sensors was proposed.

Improved NO2 gas-sensing performance of PPy by hydrogen plasma treatment: Experimental study and DFT verification

Improving gas selectivity and stability poses a challenge for gas sensors based on polypyrrole (PPy). Radio frequency hydrogen plasma was employed to modify the surface of PPy nanosheet. PPy treated with hydrogen plasma owns a larger specific surface area and an increased concentration of surface hole carriers due to the dispersion of hydrogen plasma, which results in excellent nitrogen dioxide (NO2) gas sensing performance for the PPy sensor. Furthermore, the increased electronic transfer ability and NO2 adsorption capacity of the PPy treated by hydrogen plasma were confirmed based on the calculations of Density Functional Theory (DFT). The stronger interaction of PPy treated with hydrogen plasma between PPy and NO2 have happened comparing to untreated PPy. PPy/H sensor shows a magnificent NO2 gas sensing performance (sensitivity and selectivity) due to the strong interaction (strong adsorption ability and electron transfer) between PPy and NO2 caused by the hydrogen plasma treatment. Organic semiconductor treatment with hydrogen plasma offers a novel method for surface modification of PPy applied to gas sensing.

Real-Time Monitoring of Air Discharge in a Switchgear by an Intelligent NO2 Sensor Module.

An air-insulated power equipment adopts air as the insulating medium and is widely implemented in power systems. When discharge faults occur, the air produces decomposition products represented by NO2. The efficient NO2 sensor enables the identification of electrical equipment faults. However, single-sensor-dependent NO2 detection is vulnerable to interfering gases. Implementing the sensor array could reduce the interference and improve detection efficiency. In the field of NO2 detection, In2O3 sensors have exhibited tremendous advantages. In our work, four composites based on In2O3 are integrated into sensor arrays, which could detect 250 ppb of NO2 and exhibit excellent selectivity when simultaneously exposed to CO. To further reduce the impact of humidity on gas-sensing performance, a convolutional neural network and a long short-term memory model equipped with an attention mechanism are proposed to evaluate NO2 concentration within 1 ppm, and the detection error is 63.69 ppb. In addition, the NO2 concentration estimation platform based on a microgas sensor is established to detect air discharge faults. The average concentration of NO2 generated by 10 consecutive discharge faults at 15 kV is 726.58 ppb, which indicates severe discharge in the switchgear. Our NO2 estimation method has great potential for large-scale deployment in low- and medium-voltage switchgears.

Recent Advances in Functionalization and Hybridization of Two‐Dimensional Transition Metal Dichalcogenide for Gas Sensor

Two‐dimensional (2D) transition metal dichalcogenides (TMDs) have garnered significant attention in gas‐sensing applications due to their sensitive response to a wide range of gas molecules and their ability to operate at low temperatures, resulting in low‐power consumption. However, there are several areas that require improvement, including insufficient sensitivity at low detection limits, limited gas selectivity, low reliability, and poor recovery. To address these issues and enhance the performance of gas sensors, researchers have proposed the functionalization and hybridization of 2D TMDs. This review paper focuses on elucidating the synergistic effects of functionalization and hybridization of 2D TMDs with carbon‐related materials, metals, MOs, and metal chalcogenides. The paper presents an in‐depth analysis of the mechanisms involved in enhancing the performance of 2D TMD gas sensors and explores various synthesis methods for achieving functionalization and hybridization. Furthermore, the challenges currently faced in the field are discussed and offer insights into the future prospects of TMD nanocomposite‐based gas sensors. By comprehensively addressing these aspects, this research aims to contribute to the advancement of gas‐sensing technology using TMD nanocomposites.

Highly sensitive ethanol sensor based on Ag NP-modified SnO2–In2Sn2O7-x ternary composite enhanced by synergistic catalysis

In this paper, the noble metal Ag-modified SnO2–In2Sn2O7-x ternary nanocomposites were designed to detect ethanol efficiently. Firstly, the SnO2–In2Sn2O7-x nanocomposites were synthesized by a simple hydrothermal method, and the microstructure of the SnO2 nanomaterials were adjusted by controlling the content of In2Sn2O7-x. With the increase of In2Sn2O7-x content, the morphology of the synthesized SnO2–In2Sn2O7-x composites gradually tends to be regular with porous spherical morphology. In the same synthesis conditions, the porous spherical morphology of SnO2–In2Sn2O7-x composites was more uniform at 0.5 at% of In element content, and the distribution in the material was more homogeneous and dispersed, which was conducive to the diffusion and adsorption of gases on the surface of the material, as well as to the loading of Ag nanoparticles. On this basis, the Ag nanoparticles were successfully modified through the chemical reduction route, and the Ag nanoparticles modified SnO2–In2Sn2O7-x with 0.5 at% In elemental content ternary nanocomposites were prepared. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectrometer (EDS) were used to characterize the structure and morphology of the prepared gas-sensitive materials. The gas-sensing performance of SnO2, In2Sn2O7-x, SnO2–In2Sn2O7-x, and Ag-modified SnO2–In2Sn2O7-x sensors were tested systematically. The results showed that the 1.5 wt% Ag-modified SnO2–In2Sn2O7-x nanocomposites with 0.5 at% In elemental content have good gas-sensing properties. The response of the sensor to 100 ppm ethanol vapor can reach 666 at the optimal operating temperature of 250 °C, and the response time is shortened to 45 s. It has good sensitivity for ethanol gas, and the minimum detectable gas concentration is reduced to 500 ppb. The improved performance of the sensor is primarily due to the construction of the heterogeneous interface of the SnO2 and In2Sn2O7-x and the catalytic synergism of the noble metal Ag.