Low-temperature Gas Sensors Research Articles

Perovskite CsPbBr3 quantum dots enhanced In2O3 nanospheres for triethylamine detection at low temperature

In recent years, the vigorous industrial development of the country has brought about serious air pollution, and the development of low-temperature gas sensors with high response and short response/recovery time has become ideal for monitoring the industrial environment. This work demonstrates a composite gas sensor based on CsPbBr3 perovskite quantum dots (QDs) and In2O3 nanospheres for the detection of TEA gases at low temperatures. Compared with pure In2O3, the best responsive gas for the In2O3-CsPbBr3 QDs composite was triethylamine (TEA), with a response value of 52.92 at an optimal operating temperature of 60 °C. In addition, due to the sensitive optical properties of the CsPbBr3 QDs, UV irradiation of the In2O3-CsPbBr3 composites was performed, and the samples were found to have response values as high as 156.42. The In2O3-CsPbBr3 composite also has a short response recovery time (1/19 s), which is favorable for timely warning. The results of the gas-sensing experiments showed that the sensor has good sensitivity, reproducibility, and stability for triethylamine.

Oxygen vacancy-enriched WO3 hierarchical tubes inherited from pine needle for the enhanced detection to ppb-level hydrazine at near room temperature

It is of great importance to develop low-temperature gas sensors for monitoring hydrazine (N2H4) with high toxicity and easy explosion. However, how to highly sense its ppb-level concentration remains challenging. For this purpose, biomorphic WO3 structure replicated by small-size nanoparticles was simply prepared though air calcinations of tungsten salt-immersed pine needle (PN) template. The mesoporous WO3-PN tubes with pore volume of 0.096 cc·g−1 had relatively large specific surface area (38 m2·g−1) for exposing more active sites, as well as rich oxygen vacancies (g = 2.005) and small band gap for promoting electron migration. With the assistance of W6+ Lewis acid catalytic sites, such unique multilevel structure facilitated the rapid transport and adsorption of basic N2H4 molecules, as well as their chemical reactions with high content of oxygen species (37.4 %) in sensing layer, thus first achieving the highly sensitive detection of ppb-level N2H4 gas at near room temperature. At 50 °C, WO3-PN sensor exhibited ultra-high response (S = 307), fast response time (Tres = 16 s) for 1 ppm N2H4, and low actual detection concentration (5 ppb). These key indicators were remarkably superior to reported semiconductor gas sensors. In addition, the enhanced low-temperature sensing mechanism of WO3-PN sensor was explored by means of analytical tests and DFT calculations.

Highly Sensitive Diethylamine Detection at Room Temperature Using g-C3N4 Nanosheets Decorated with CuO Hollow Polyhedral Structures.

Chemiresistive-based metal oxide semiconductor (MOS) gas sensors are widely used in gas sensing due to their advantageous properties. Graphitic carbon nitride (g-C3N4) and metal oxide heterostructure materials can improve charge transport properties, selectivity, and sensitivity in MOS gas sensor materials. Herein, for the first time, CuO hollow polyhedral structures (HPSs) were synthesized via a hydrothermal technique and annealed at different temperatures, with the 400 °C annealed (CuO-400 HPSs) demonstrating remarkable sensing capabilities for diethylamine (DEA) gas at room temperature (RT). The x-g-C3N4 nanosheets were decorated with CuO HPSs in varying amounts (x = 0.8, 1.8, 2.1, and 3.1 wt %) and then annealed at 400 °C for x-g-C3N4-CuO-400 hollow polyhedral heterostructures (HPHSs). Indeed, among the synthesized samples, the 1.8%-g-C3N4-CuO-400 HPHSs have a higher sensitivity to DEA (resistance change in gas (Rg) and air (Ra); Rg/Ra= 65 @ 20 ppm), a low detection limit (Rg/Ra= 6 @ 500 ppb), wide dynamic response (Rg/Ra= 190 @ 80 ppm), strong stability (30 days), and 21.6 times higher sensitivity than pure CuO at RT toward 20 ppm of DEA. The exceptional gas-sensing behavior can be attributed to various factors, including controlled annealing conditions that result in the formation of well-defined structures and greater porosity, efficient charge transfer properties resulting from an optimized ratio of g-C3N4 to CuO in HPHSs, an abundance of defects, unsaturated Cu sites, and synergistic effects. The study presents a universal strategy for generating sensitive and selective g-C3N4-based composite materials for low-temperature gas sensors.

Constructing N-Pd-O electron bridge between In2O3 nanotubes and g-C3N4 nanosheets to boost explosive gas sensing performance

Portable sensing systems can benefit greatly from low-temperature gas sensors for monitoring low-ppm volatile organic compounds (VOCs), flammable, and explosive gases in enclosed environments. Here, we developed a gas sensor for efficient detection of ethanol and low-concentration H2 at low temperatures, using exfoliated graphitic carbon nitride (g-C3N4) homogeneously loaded with mixed phases of palladium oxide (PdOx) on indium oxide (In2O3) nanotubes to reduce the operating temperature of the sensor and improve the sensitivity, response speed, and detection limit. The optimal working temperature for the sensor based on the heterojunction of g-C3N4/PdOx and In2O3 nanotubes (ECN-PdOx/In2O3) is reduced from 220 °C to 180 °C as a result of logical catalytic state regulation and the introduction of electronic and chemical sensitization by constructing N-Pd-O electron bridge between In2O3 nanotubes and g-C3N4 nanosheets to boost explosive gas sensing performance. Additionally, the gas-sensitive performance investigation revealed that the response of ECN-PdOx/In2O3 to 100 ppm ethanol was up to 320, which was 17 times higher than that of pristine In2O3 and 3.2 times greater than that of PdO-modified In2O3 (PdO/In2O3). Moreover, the sensor based on ECN-PdOx/In2O3 also showed a clear response of 1.56 to 100 ppb H2, while no obvious response of pristine In2O3 and further calculation and analysis obtained that the detection limit of ECN-PdOx/In2O3 for H2 is as low as 23 ppb.

Low-temperature gas sensor with good long-term stability based on Co3O4/Ti3C2Tx heterojunction

As one of the two-dimensional (2D) nanomaterials, MXene exhibits great potential on gas-sensing owing to its high specific area, rich functional groups and great charge transfer mobility. Herein, electrostatic adsorption and calcination strategies were taken for ZIF-derived Co3O4 and alkalized Ti3C2Tx MXene to fabricate Co3O4/MX7.5 heterojunction. It can be found that Co3O4 nanoparticles (NPs) uniformly grow on the surface of alkalized Ti3C2Tx. Alkalized Ti3C2Tx with lower work function (lower than 3.9 eV) can transfer more electrons towards Co3O4 and promote the redox of Co2+. These increased Co2+ ions can help to adsorb more adsorbed oxygen and produce more oxygen defects, which enhances contact interaction between ethanol molecules and adsorption sites. The formation of heterojunction between Co3O4 and MXene is observed by UV–vis spectra, and this interface effect enhances the ability of gas sensors. Therefore, the sensors based on the obtained Co3O4/MX7.5 heterojunction can operate at a relatively low temperature (140 °C) with a response of 3500 % and a low detection limit of 1 ppm. And it also delivers long-term stability (about 30 days). This work demonstrates practical application for detecting ethanol at a relatively low working temperature and keeping their response in a long term.

Fe-based metal-organic framework as a chemiresistive sensor for low-temperature monitoring of acetone gas

This work demonstrates the potential of a novel iron-based metal-organic framework (Fe-MOF or VNU-15) to effectively detect low-concentration volatile organic compounds (VOCs), particularly acetone (CH3COCH3). A facile solvothermal strategy was used to synthesize Fe-MOFs, comprising Fe(II)/Fe(III) and two distinct linkers—BDC (benzene-1,4-dicarboxylate) and NDC (naphthalene-2,6-dicarboxylic acid). As a first step, Fe-MOFs were characterized to determine their pure phase formation and identify their structural and morphological characteristics. Fe-MOFs processed via the solvothermal method demonstrated high crystallinity, high thermal stability, polyhedral crystal-shaped surface morphology, and a surface area of 735 m2g−1, making them suitable for gas-sensing applications. Laboratory-scale gas-sensing devices were fabricated by printing Fe-MOF powder onto patterned interdigitated electrodes, with performance measurements conducted on these devices in response to exposure to various target gases at temperatures between 25 and 200 °C and gas concentrations between 1 and 10 ppm. Gas-sensing tests confirmed that the VNU-15 sensor selectivity detects CH3COCH3 with a gas response of 1.68–10 ppm and a response time of 64 s, followed by a recovery time of 166 s at 50 °C. This study demonstrates the feasibility of using novel MOF-based sensing channels as low-temperature gas sensors, providing new insights into gas-sensing technology.

Synthesis and characterization of nanostructured Ag- and In-doped vanadium pentoxide for ethanol-sensing application

Abstract This study presents a facile method for preparing low-temperature gas sensors based on nanostructured Ag-doped and In-doped vanadium pentoxide (V2O5). Pure, In-doped, and Ag-doped V2O5 samples were synthesized using the thermal decomposition method, and thermogravimetric analysis was used to determine the optimal calcination temperature. All the samples were characterized and analyzed using field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Both Ag- and In-doped V2O5 exhibited higher sensitivity toward ethanol compared to pure V2O5. Hence, incorporating metal ions into semiconducting metal oxides holds the potential to enhance the sensitivity of gas sensors.

Ultra-high response and low temperature NO2 sensor based on mesoporous SnO2 hierarchical microtubes synthesized by biotemplating process

The development of low temperature gas sensor with ultra-high response has important application value for actual monitoring of harmful gases. Herein, we utilized poplar branch (PB) as bio-template to synthesize SnO2 sensing material through immersing PB into SnCl4.6 H2O solution, followed by calcining the immersed precursor in air. The material calcined at 600 ℃ (named as SnO2-600) exhibits the hierarchical microtube structure inherited from PB, which is cross-linked by small-sized nanoparticles. Meanwhile, uniform mesoporous structure and abundant oxygen vacancies are also present on the inner and outer surface of SnO2-600 microtubes. The synergistic effect of these microstructure characteristics can not only greatly enhance surface chemical reaction of sensing materials, but also effectively improve surface diffusion, adsorption and desorption behavior of target gas. At 50 ℃, SnO2-600 sensor presents high response value (S = Rg/Ra) of 3411 and rapid recovery time of 17 s to 10 ppm NO2. In addition, the sensor also has low detection limit, good selectivity, satisfactory reproducibility, humidity resistance and long-term stability. Therefore, the present mesoporous SnO2-600 microtubes are available as candidate for detecting NO2 gas at low temperature.

Flexible Low-Temperature Ammonia Gas Sensor Based on Reduced Graphene Oxide and Molybdenum Disulfide

Owing to harsh working environments and complex industrial requirements, traditional gas sensors are prone to deformation damage, possess a limited detection range, require a high working temperature, and display low reliability, thereby necessitating the development of flexible and low-temperature gas sensors. In this study, we developed a low-temperature polyimide (PI)-based flexible gas sensor comprising a reduced graphene oxide (rGO)/MoS2 composite. The micro-electro-mechanical system technology was used to fabricate Au electrodes on a flexible PI sheet to form a “sandwiched” sensor structure. The rGO/MoS2 composites were synthesized via a one-step hydrothermal method. The gas-sensing response was the highest for the composite comprising 10% rGO. The structure of this material was characterized, and a PI-based flexible gas sensor comprising rGO/MoS2 was fabricated. The optimal working temperature of the sensor was 141 °C, and its response-recovery time was significantly short upon exposure to 50–1500 ppm NH3. Thus, this sensor exhibited high selectivity and a wide NH3 detection range. Furthermore, it possessed the advantages of low power consumption, a short response-recovery time, a low working temperature, flexibility, and variability. Our findings provide a new framework for the development of pollutant sensors that can be utilized in an industrial environment.

Flower-like MoS2 hierarchical architectures assembled by 2D nanosheets sensitized with SnO2 quantum dots for high-performance NH3 sensing at room temperature

Flower-like MoS2 hierarchical architectures assembled by ultrathin 2D nanosheets decorated with SnO2 quantum dots (QDs) were successfully prepared through a solvothermal method and used for room-temperature NH3 sensing detection. The morphology and structure of as-prepared hierarchical architectures were fully characterized, showing that SnO2 QDs with uniform particle size of 2–4 nm were uniformly distributed on the ultrathin nanosheets of MoS2 hierarchical architectures. SnO2 QDs@MoS2 composites based gas sensor exhibited a high response of 8.6 and short response/recovery times of 6 s/121 s to 100 ppm NH3 with good selectivity, excellent repeatability, and outstanding long-term stability at room temperature of 25 °C. Such highly enhanced response toward NH3 was ascribed to the synergistic effect between active SnO2 QDs with abundant dangling bonds and MoS2 nanosheets with large specific surface area and high carrier mobility. This work presented a potential room-temperature sensing material and revealed the underlying sensitization mechanism of the quantum dots, offering new ideas for the development of low-temperature gas sensors.

Heterogeneous Co3O4/AgO nanorods for conductometric triethylamine sensing at 90 °C

To achieve room or low temperature gas sensitivity with low power consumption has been a challenging task for metal oxide semiconductor gas sensors. In this work, heterogeneous Co3O4/AgO nanorods are synthesized by wet-chemical method. The structural and compositional characterizations show that AgO nanoparticles are highly dispersed on the surface of Co3O4 nanorods. It is found that the AgO nanoparticles can trigger both catalytic and electronic sensitization that lead to improved sensor properties. Consequently the sensor based on Co3O4/AgO delivers a remarkable response to triethylamine (TEA) at room temperature (RT) and the best response at 90 °C, which is much lower compared to that (195 °C) of pristine Co3O4. In addition, the sensor shows fast response time (44 s) and low limit of detection (65 ppb), good selectivity and repeatability for TEA detection. This work provides an effective strategy for developing low temperature gas sensors based on p-type metal oxides.

High-performance room temperature NO2 gas sensor based on visible light irradiated In2O3 nanowires

A batch of In2O3 nanowires (NWs) samples were prepared through a simple electrospinning method and the following sintering procedure. The X-ray powder diffraction (XRD) analysis identified their high purity and crystallinity. Furthermore, the field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed the high quality of the synthesized products. The nanowires were homogeneous and of uniform diameter. The X-ray photoelectron spectroscopy (XPS) data showed that the oxygen vacancies and surface chemisorbed oxygen species occupied a large proportion in the total oxygen content. O2-temperature-programmed desorption (TPD) experiments identified the affinity of oxygen to In2O3 nanowires´ surface at room temperature and concrete adsorbed oxygen species. The above results were positive signals of their gas-sensing performance. In the subsequent gas-sensing test, we found that the sensor based on In2O3 NWs exhibited a high selectivity toward NO2 under room temperature. What's more, the response of the sensor toward 5 ppm NO2 at 25 ℃ in dark could reach as high as 740 and its detection limit was as low as 10 ppb. However, like most reported literatures on low-temperature gas sensors, the In2O3 NWs sensor likewise had a significant defect of long recovery process. Fortunately, we successfully solved this defect through the introduction of visible light irradiation during the recovery process. We detailedly explored the relationship between the light intensity and wavelength and the recovery properties of the sensor. Based on an in-depth analysis on the above two parameters and O2-TPD data, we proposed two different action mechanisms of photons according to their energy difference when accelerating the recovery of the sensor.

Rose-Like MoO₃/MoS₂/rGO Low-Temperature Ammonia Sensors Based on Multigas Detection Methods

In order to improve the sensitivity of the pure MoO3 sensor to ammonia and reduce its operating temperature, MoO3/MoS2/rGO was prepared in this work, and the gas-sensitive performance of MoO3/MoS2/rGO was studied. The results of the static gas sensitivity test show that, compared with pure MoO3, MoO3/MoS2/rGO greatly improves the response of the sensor to ammonia at low temperature. Moreover, this article discusses the multigas detection methods by waveform-matched dynamic temperature modulation based on low-temperature gas sensor composites of rose-like MoO3/MoS2/rGO, which is used to solve the shortcoming of poor selectivity of metal–oxide–semiconductor gas sensor. Multigas (including acetone, methanol, ethanol, benzene, toluene, and ammonia) detection methods by waveform-matched dynamic temperature modulation are investigated, in which the experimental results show that the dynamic response curves of the sensor have obvious differences to each gas under different temperature waveform modulations. Temperature modulation waveforms with different periods and variations are investigated, including rectangular wave, triangular wave, and sine wave. This provides a feasible way to improve the selectivity of the sensor. In order to establish and verify the accuracy of the multigas detection model, 100 sets of response curves are selected for each waveform. Finally, the gas-sensing mechanism of gas-sensitive materials to ammonia is analyzed. Preparation of highly sensitive materials, dynamic testing, and gas identification methods can provide the technical basis for the application of gas sensors.

Ultrasensitive and low temperature gas sensor based on electrospun organic-inorganic nanofibers

Abstract Organic-inorganic hybrid material is one of the most promising materials for high performance gas sensors due to its improved properties like high sensitivity, selectivity, fast response time, flexibility and low power consumption. This work presents ultrasensitive, selective and low operating temperature H2S gas sensor. It is based on metal-oxide nanoparticles (NPs) embedded in organic semiconductor polymeric nanofibrous (NFs) membrane containing an ionic liquid (IL). In this context, high surface area Tungsten(VI) oxide- Polyvinyl alcohol (WO3-PVA) nanofibrous composite sensor material with average diameter of 130 ± 20 nm were synthesized with controlled morphology and interconnectivity through an electrospinning technique. The obtained WO3 NPs-containing PVA nanofibrous sensing material was evaluated for its ability as a potential sensor for H2S gas at different operating temperatures and gas concentrations. Results demonstrated that the fabricated sensor is ultrasensitive and selective for H2S gas and exhibit an excellent reproducibility, and long-term stability. Furthermore, the sensor showed adequate response in a humid environment. It was also shown that nanofibers' membrane porosity and thickness control the sensing performance. The optimum operating temperature of 40°C with a detection threshold as low as 100 ppb with a response time of 16.37 ± 1.42 s were achieved. This combined high sensitivity, fast response time and low operating temperature (low-power consumption) provides clear evidence of the sensor's potential to outperform existing devices, which could pave the way for a commercial exploitation.

Enhanced NO2 sensing aptness of ZnO nanowire/CuO nanoparticle heterostructure-based gas sensors

Designing heterostructure materials for better gas sensing performance is a key for obtaining low-temperature gas sensor device technologies. Herein, CuO nanoparticle-ZnO nanowire heterostructure-based gas sensors have been fabricated by thermal evaporation followed by annealing in argon and air atmospheres and named respectively as NWG and NWA sensors. X-ray diffraction demonstrates the monoclinic structure of CuO and hexagonal wurtzite structure of ZnO and, thus, the formation of heterostructure. Morphological analysis confirms the ZnO nanowires (NWs) were well-linked to CuO nanoparticles (NPs). At an optimized temperature of 150 °C, the heterostructure sensor exhibits a maximum response (NWG, 175%) to NO2 over other oxidizing/reducing target gases on the exposure of 100 ppm concentration. This heterostructure sensor, noteworthy, responds to an extremely low exposure of NO2 gas (1 ppm). The interactions of oxidizing NO2 gas with ZnO/CuO heterostructure sensors has effectively been scrutinized using impedance spectroscopy analysis.

A novel ammonia gas sensors based on p-type delafossite AgAlO2

Exploring novel ammonia sensors operated at room temperature holds great promise for various applications. Herein, we synthesized p-type delafossite AgAlO2 nanoparticles via hydrothermal method. The nanoparticles show a single Ag-deficient 3R delafossite phase with particle size between 200 and 500 nm. The sensor based on AgAlO2 nanoparticles exhibits high sensitivity, fast response-recovery and good selectivity to 100 ppm ammonia at 293 K 20–70 %RH. More interestingly, the sensor shows a pseudo n-type response to ammonia at 293 K 35 %RH, but a p-type sensing behavior at elevated temperature of 573 K. The temperature-dependent pseudo n-type response to ammonia gas is ascribed to the competition of extrinsic and intrinsic sensing behaviors, which resulted from the reaction of ammonia gas with surface adsorbed water molecules and adsorbed oxygen ions, respectively. The former can regulate the conduction of the adsorbed water layer, which contributes to the total conductivity as an external part, while the latter can modulate the intrinsic conductivity of the sensor by changing the hole concentration of AgAlO2. This work might provide a new idea to design low temperature gas sensors.

A low temperature, highly sensitive and fast response toluene gas sensor based on In(III)-SnO2 loaded cubic mesoporous graphitic carbon nitride

Abstract Low temperature gas sensors for monitoring low ppm volatile organic compounds (VOCs) in indoor climate have critical advantages in designing portable sensing devices. Herein, a highly sensitive as well as fast response In(III)-SnO2 loaded cubic mesoporous mpg-CN (commonly known as g-C3N4) based toluene gas sensor has been fabricated through template inversion of KIT-6. When exposed to a variety of test VOCs at 200 °C, the In(III)-SnO2/mpg-CN (1% In) showed a highly selective response (Ra/Rg = 61.4) and fast reversible response/recovery (4/2 s) to 50 ppm toluene gas. The sensor was also able to selectively detect 50 ppm (R = 2.4) and 100 ppm (R = 3.6) toluene gas at 90 °C. Compared to mesoporous In(III)-SnO2, the mpg-CN supported In(III)-SnO2 nanocomposite shows ∼2 fold increase in response to toluene gas while reducing the optimized operating temperature by 50 °C. The significant enhancement in sensitivity and lowering down of optimized operating temperature is attributed to the higher surface area, easily accessible mesopore channels of 3D mesoporous cubic structure and suitable heterojunction formation by the semiconducting In(III)-SnO2/mpg-CN nanocomposite. The findings reported in this study shows promising glimpse for designing a novel strategy to the development of ultrasensitive VOCs sensors working at low operating temperature.

Electro-physical properties of thin films based on metal-containing polyacrylonitrile for application in low temperature gas sensors

The metal-containing (Cu, Co, Ag, Cr) polyacrylonitrile (PAN) thin films were fabricated using IR-pyrolysis under low vacuum conditions in different temperature and time modes. The thickness of the fabricated films was between 0.01÷0.68 μm. The metal-containing PAN films had the resistance values in the range from 2.9·102 to 5.1·1011 Ohm. It has been investigated that the film thickness, resistance and gas sensitivity of the samples depends on the composition of the initial solution and on the process parameters of the film material’s fabrication. It has been studied that the samples demonstrate gas-sensing properties to CO, NO2, Cl2 and gasoline vapours at room temperature.

Influence of copper incorporation in CdS: Structural and morphological studies

CdS and copper doped CdS thin film were synthesized by CBD method and characterized using XRD, EDAX, FESEM, TEM and UV–Vis spectrophotometer. Structural characterization reveals presence of cubic phase. EDAX analysis shows nearly stoichiometric films with presence of Cu in few amounts. The particle size of CdS (∼16–26 nm) decreased with copper doping. The bandgap decreased from 2.54 eV to 2.47 eV with increase in copper incorporation. Reflectance and transmittance measurements were studied to get information about optical property. The electrical conductivity and dielectric property were investigated using impedance spectroscopy. Semiconducting metal oxides (SMO) commonly employed in gas sensors requires high operating temperatures. Metal sulphide thin films can be a potential sensing material for new age low temperature gas sensors. An enhancement is sensitivity was observed due to incorporation of copper in CdS and a significantly high sensitivity of ∼57% for copper doped CdS was exhibited at a reasonably low temperature of 150 °C in presence of 200 ppm LPG.

A novel low temperature gas sensor based on Pt-decorated hierarchical 3D SnO2 nanocomposites

A novel gas sensor composed of Pt nanoparticles-decorated hierarchical SnO2 nanostructures (Pt–SnO2) was synthesized via a facile dipping-precipitation strategy. Pt nanoparticles with small sizes (avg. 4nm) were successfully dispersed onto our pre-synthesized 3D hierarchical SnO2 nanoflowers supports by using lysine as both capping and linking agents. The morphology, structure and composition of the as-prepared samples were characterized by means of field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Comparisons of the gas sensing performance between pure SnO2 and Pt–SnO2 nanocomposites revealed that after supporting Pt nanoparticles, the decorated sensor not only got an optimal working temperature of as low as 100°C, but also exhibited faster response and recovery speeds and higher response than the pristine one at such low temperature. Moreover, good selectivity and excellent stability were also shown for the hybrid sensor. Sensing mechanisms were illustrated to help explain the strong spillover effect of the Pt nanoparticles and the Schottky barriers at the interface of metal and semiconductor, both of which facilitated the low temperature sensing performance. The Pt–SnO2 sensors are considered to be a promising candidate for trace environmental gas detections in practical use.