Platinum-Supported Cerium-Doped Indium Oxide for Highly Sensitive Triethylamine Gas Sensing with Good Antihumidity

Enhanced Gas Adsorption and Robust Multi-Interface Charge Transfer in Ternary Co3O4/ZnIn2S4/Pt Heterostructure Arrays for Efficient Triethylamine Detection

The resistive gas sensors based on semiconductor materials provide an effective strategy for the detection of harmful gases. However, the limitations of surface gas adsorption activity and interface charge transfer efficiency of semiconductor sensing materials, as well as the complex device fabrication process, pose significant challenges to the development of sensors. Here, a ternary Co3O4/ZnIn2S4/Pt heterostructure arrays gas sensor is designed, which consists of Co3O4 nanowire arrays grown in situ on an alumina flat substrate as backbones, ultrathin ZnIn2S4 nanosheets wrapped around the surface of Co3O4 nanowires, and highly dispersed Pt nanoparticles on the outermost layer. It enables superior sensing performance for the detection of the volatile organic compound triethylamine, which exhibits a significant response of ∼118.97 (Ra/Rg) toward 100 ppm of triethylamine at a relatively low working temperature of 200 °C, along with excellent response/recovery speed, selectivity, and enduring stability (over 3 months). Based on first-principles calculation and a series of spectroscopic characterization (including in situ spectroscopy), it is revealed that the heterostructure arrays exhibited enhanced adsorption activity for both oxygen and triethylamine molecules. Most importantly, the robust p-n heterointerface (Co3O4/ZnIn2S4) and semiconductor-metal heterointerface (Co3O4/Pt, ZnIn2S4/Pt) are formed in the ternary heterostructure, achieving efficient multi-interface charge transfer characteristics. In addition, thanks to the design of in situ 1D/2D/0D porous array structures, the ternary Co3O4/ZnIn2S4/Pt heterostructure arrays not only have large specific surface areas for gas reaction but also simplify device manufacturing. This research offers novel perspectives on boosting the gas sensing performance of semiconductor materials through the comprehensive design of ternary heterostructures with robust multi-interfaces.

Amorphous Carbon-Loaded WO3 Nanosheet Arrays for ppb-Level NO2 Sensing with Improved Anti-Humidity Property

Metal-oxide-based gas sensors have attracted considerable interest due to their low cost, high sensitivity, quick response, and ease of miniaturization and integration. Unfortunately, metal oxides are susceptible to the interference of moisture, which brings about hydroxyl poisoning of the sensing layer and decrement in baseline resistance and sensor performance. In this study, WO3 films were modified with a porous amorphous carbon layer. The as-loaded amorphous carbon layer improves simultaneously the adsorption capacity of WO3 and hydrophobicity of the surface, which endows the composite films with not only surpassing NO2 sensitivity at the parts per billion level but also enhanced immunity to humidity. The incorporation of amorphous carbon with metal oxides is expected to be a general route for the fabrication of high performance, antihumidity gas sensors.

High Performance H2S Sensor Based on Ordered Fe2O3/Ti3C2 Nanostructure at Room Temperature

The utilization of a heterogeneous nanojunction design has shown significant enhancements in the gas sensing capabilities of traditional metal oxide gas sensors. In this study, a novel room temperature H2S gas sensor employing Fe2O3 functionalized Ti3C2 MXene as the sensing material has been developed. This sensor exhibits a broad detection range (0.01-500 ppm), low detection limit (10 ppb), and rapid response/recovery times (10 s/15 s), making it ideal for ppb-level H2S detection. The exceptional gas sensitivity of Fe2O3/Ti3C2 composite to H2S can be attributed to several key factors. First, the unique layered frame structure of Fe2O3/Ti3C2 significantly amplifies the surface area of the hybrid material, enhancing the absorption and diffusion capabilities of H2S molecules. Second, the abundance of functional groups (-O, -OH, and -F) on the surface of Ti3C2 MXene nanosheets provides additional active sites for H2S adsorption, The density functional theory calculation confirms that the adsorption energy of the Fe2O3/Ti3C2 composite for H2S (-2.93 eV) is significantly lower than that of pure Fe2O3 (-2.37 eV) and Ti3C2 (-0.2 eV). Lastly, the remarkable metal conductivity of Ti3C2 MXene ensures efficient electron transfer, thereby enhancing overall sensing performance.

Mesoporous CdO/CdGa2O4 microsphere for rapidly detecting triethylamine at ppb level

Developing fast, accurate and sensitive triethylamine gas sensors with low detection limits is paramount to ensure the safety of workers and the public. However, sensors based on single metal oxide materials still suffer from drawbacks such as low response sensitivity and long response and recovery times. To address these challenges, in this work, a series of mesoporous CdO/CdGa2O4 microspheres were synthesized. We optimized the sensor's sensing performance to triethylamine by fine-tuning the ratio of CdO to CdGa2O4. Among them, CdO:3CdGa2O4-based sensor demonstrates a rapid response time of 2 s to detect 100 ppm of triethylamine, with a high response value of 211 and exceptional selectivity. Furthermore, it exhibits a low detection limit of 20 ppb for triethylamine, making it suitable for practically testing fish freshness. Crucially, electron transfer between the heterojunctions increases the chemically adsorbed oxygen on the materials' surface, thereby enhancing the sensor's response sensitivity to triethylamine. This discovery provides new insights and methodologies for the design of highly efficient triethylamine gas sensors.

Enhanced Interface Charge Carrier Transport of SnO2/CeO2 via Oxygen Vacancy Synergized Heterojunction for Triethylamine Sensing Property

Efficient charge carrier transport characteristics are critical to achieving the excellent performance of metal-oxide semiconductor gas sensors. Herein, SnO2/CeO2 heterojunction layered nanosheets with abundant oxygen vacancies were successfully synthesized through a simple solvothermal assisted high-temperature calcination method. The synergistic effect of oxygen vacancies and heterojunctions promoting the charge carrier transport properties at the SnO2/CeO2 interface for the enhanced sensing properties of triethylamine (TEA) was highlighted. As a result, the optimized SnO2/CeO2 exhibits improved gas sensing performance at 173 °C to 50 ppm of TEA. These include high response (205), excellent selectivity, low detection limit, and good long-term stability. This enhanced gas sensing property of SnO2/CeO2 is mainly attributed to the fact that the heterojunction and oxygen vacancies act as dual active sites synergistically inducing electron transfer, thereby effectively modulating the transport properties of the interfacial charge carriers, and thus facilitate the surface reactions efficiently. In this work, the dual-engineering strategy of synergistic interaction of heterojunction and oxygen vacancies can provide new perspectives for the design of advanced gas sensing materials.

Applications of cerium-based materials in food monitoring

With the rapid development of society, food safety to public health has been a topic that cannot be ignored. In recent years, lanthanide-based materials are studied to be potential candidates in the detection of food samples. Cerium (Ce)-based materials (such as Ce ions, CeO2, Ce-metal organic framework (Ce-MOF), etc.) have also attracted more attention in food detection by virtue of colorimetric, fluorescence, sensing, and other methods. This is because the mixed valence of Ce (Ce3+ and Ce4+), the formation of oxygen vacancies, and their optical and electrochemical properties. In this review, Ce-based materials will be introduced and discussed in the field of food detection, including biogenesis, construction, catalytic mechanisms, combination, and applications. In addition, the current challenges and future development trend of these Ce-based materials in food safety detection are also proposed and discussed. Therefore, it is meaningful to explore the Ce-based materials for detection of biomarkers in food samples.

Emerging single-atom catalysts in the detection and purification of contaminated gases

Single atom catalysts (SACs) show exceptional molecular adsorption and electron transfer capabilities owing to their remarkable atomic efficiency and tunable electronic structure, thereby providing promising solutions for diverse important processes including photocatalysis, electrocatalysis, thermal catalysis, etc. Consequently, SACs hold great potential in the detection and degradation of pollutants present in contaminated gases. Over the past few years, SACs have made remarkable achievements in the field of contaminated gas detection and purification. In this review, we first provide a concise introduction to the significance and urgency of gas detection and pollutant purification, followed by a comprehensive overview of the structural feature identification methods for SACs. Subsequently, we systematically summarize the three key properties of SACs for detecting contaminated gases and discuss the research progress made in utilizing SACs to purify polluted gases. Finally, we analyze the enhancement mechanism and advantages of SACs in polluted gas detection and purification, and propose strategies to address challenges and expedite the development of SACs in polluted gas detection and purification.

Selective Oxidation of Triethylamine Catalyzed by Mn-Ce/ZSM-5

The selective catalytic oxidation (SCO) of triethylamine (TEA) to harmless nitrogen (N₂), carbon dioxide (CO₂), and water (H₂O) is of green elimination technology. In this paper, Mn-Ce/ZSM-5 with different proportions of MnO_x/CeO_x were studied for the selective catalytic combustion of TEA. The catalysts were characterized by XRD, BET, H₂-TPR, XPS, and NH₃-TPD and their catalytic activities were analyzed. The results showed that MnO_x was the main active component. The addition of a small amount of CeO_x promotes the generation of high-valence Mn ions, which reduces the reduction temperature of the catalyst and increases the redox capacity of the catalyst. In addition, the synergistic effect between CeO_x and MnO_x significantly improves the mobility of reactive oxygen species on the catalyst, thus improving the catalytic performance of the catalyst. The catalytic oxidation performance of TEA over 15Mn5Ce/ZSM-5 is the highest. TEA can be completely converted at 220 °C, and the selectivity for N₂ is up to 80%. The reaction mechanism was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS).

ZnO Nanorod-Immobilized Pt Single-Atoms as an Ultrasensitive Sensor for Triethylamine Detection

Triethylamine (TEA) is a flammable and highly toxic gas, and the fast, accurate, and sensitive detection of gas TEA remains greatly challenging. Herein, we report a ZnO nanorod anchored with a single-atom Pt catalyst (Pt₁/ZnO) as a gas sensor for TEA detection. The sensor shows high selectivity and high response to gas TEA with a response value of 4170 at 200 °C, which is 92 times higher than that of pure ZnO. Moreover, the Pt₁/ZnO sensor has very short response and recovery times of only 34 and 76 s, respectively, and also has a high response to ppb-level TEA gas (100 ppb-21.6). The gas-sensing enhancement mechanism of the Pt₁/ZnO sensor to gas TEA was systematically investigated using band structure analysis, in situ diffuse reflectance infrared Fourier transformation spectroscopy, and density functional theory calculations. The results show that the oxygen vacancies on Pt₁/ZnO can effectively activate the adsorbed oxygen. Moreover, chemical bonds can be formed between Pt single atoms and N atoms in TEA to achieve effective adsorption and activation of TEA molecules, facilitating the reaction between TEA and the adsorbed oxygen on Pt₁/ZnO, and thereby obtaining high gas-sensing performance. This work highlights the crucial role of Pt single-atom in improving the sensing performance for gas TEA detection, paving the way for developing more advanced gas sensors.

Polymerization-Induced Aggregation Approach toward Uniform Pd Nanoparticle-Decorated Mesoporous SiO2/WO3 Microspheres for Hydrogen Sensing

Hydrogen as an important clean energy source with a high energy density has attracted extensive attention in fuel cell vehicles and industrial production. However, considering its flammable and explosive property, gas sensors are desperately desired to efficiently monitor H₂ concentration in practical applications. Herein, a facile polymerization-induced aggregation strategy was proposed to synthesize uniform Si-doped mesoporous WO₃ (Si-mWO₃) microspheres with tunable sizes. The polymerization of the melamine-formaldehyde resin prepolymer (MF prepolymer) in the presence of silicotungstic acid hydrate (abbreviated as H₄SiW) leads to uniform MF/H₄SiW hybrid microspheres, which can be converted into Si-mWO₃ microspheres through a simple thermal decomposition treatment process. In addition, benefiting from the pore confinement effect, monodispersed Pd-decorated Si-mWO₃ microspheres (Pd/Si-mWO₃) were subsequently synthesized and applied as sensitive materials for the sensing and detection of hydrogen. Owing to the oxygen spillover effect of Pd nanoparticles, Pd/Si-mWO₃ enables adsorption of more oxygen anions than pure mWO₃. These Pd nanoparticles dispersed on the surface of Si-mWO₃ accelerated the dissociation of hydrogen and promoted charge transfer between Pd nanoparticles and WO₃ crystal particles, which enhanced the sensing sensitivity toward H₂. As a result, the gas sensor based on Pd/Si-mWO₃ microspheres exhibited excellent selectivity and sensitivity (R_air/R_gas = 33.5) to 50 ppm H₂ at a relatively low operating temperature (210 °C), which was 30 times higher than that of the pure Si-mWO₃ sensor. To develop intelligent sensors, a portable sensor module based on Pd/Si-mWO₃ in combination with wireless Bluetooth connection was designed, which achieved real-time monitoring of H₂ concentration, opening up the possibility for use as intelligent H₂ sensors.

Recent Progress on Anti-Humidity Strategies of Chemiresistive Gas Sensors

In recent decades, chemiresistive gas sensors (CGS) have been widely studied due to their unique advantages of expedient miniaturization, simple fabrication, easy operation, and low cost. As one ubiquitous interference factor, humidity dramatically affects the performance of CGS, which has been neglected for a long time. With the rapid development of technologies based on gas sensors, including the internet of things (IoT), healthcare, environment monitoring, and food quality assessing, the humidity interference on gas sensors has been attracting increasing attention. Inspiringly, various anti-humidity strategies have been proposed to alleviate the humidity interference in this field; however, comprehensive summaries of these strategies are rarely reported. Therefore, this review aims to summarize the latest research advances on humidity-independent CGS. First, we discussed the humidity interference mechanism on gas sensors. Then, the anti-humidity strategies mainly including surface engineering, physical isolation, working parameters modulation, humidity compensation, and developing novel gas-sensing materials were successively introduced in detail. Finally, challenges and perspectives of improving the humidity tolerance of gas sensors were proposed for future research.

Pd-SnO2/In2O3 with a Unique Structure for the Ultrasensitive Detection of Triethylamine near Room Temperature

Triethylamine (TEA) is a serious threat to people's health, and it is still a challenge to detect TEA at ppb level near room temperature (RT). Herein, we developed a simple, low-cost, low-temperature, and ultra-sensitive TEA sensor based on Pd-SnO₂/In₂O₃ composites. First, SnO₂ nanoparticles were obtained by the pyrolysis of Sn-MOF@SnO₂ precursor (MOF: metal organic framework), and Pd-SnO₂/In₂O₃ composites were prepared by further compounding and doping. The results show that the Pd-SnO₂/In₂O₃ sensor is highly sensitive to TEA gas at near RT (at 60 °C, the sensor response to 10 ppm TEA is 12,000, the response/recovery (res/rec) time is 51 s/493 s, and at 30 °C, the response value also reaches 1380, the res/rec time is 66 s/610 s), along with good selectivity, stability, and moisture resistance. Even at 10 °C operating temperature and 75% relative humidity (RH) in a low-temperature and high-humidity environment, it still maintains a high sensitivity of over 1000 to 10 ppm TEA, which shows great application potential in TEA detection. The reason for the enhanced performance of the 0.5%Pd-SnO₂/In₂O₃ sensor can be attributed to a large number of adsorbed oxygens on the unique structure of the material, the good charge transfer ability of the n-n-type heterojunction between SnO₂ and In₂O₃, the chemical sensitization and electronic sensitization of Pd nanoparticles, and the catalytic spillover effect. This work will provide a new approach for preparing sensors with good comprehensive properties, making full use of the advantages of the material structure-activity relationship.

Highly sensitive triethylamine gas sensor by Pt-loaded p-n heterojunction Co3O4/WO3

Triethylamine (TEA) exists widely in production and life and is extremely volatile, which seriously endangers human health. It is required to develop high-performance TEA sensors to protect human health. We fabricated Pt-Co₃O₄/WO₃based on our previous work, and the performance was tested against volatile organic compounds. Compared with the previous work, its operating temperature was greatly reduced from 240 °C to 180 °C. The response value of Pt-Co₃O₄/WO₃was increased from 1101 to 1532 for 10 ppm TEA with good selectivity. These results show a significant step toward practical use of the Pt-Co₃O₄/WO₃sensor.

Mixed potential type sensor based on Gd2Zr2O7 solid electrolyte and BiVO4 sensing electrode for effective detection of triethylamine

Triethylamine (TEA), as a common and widely used industrial raw material, is extremely hazardous to the environment and human health. Therefore, the development of a portable gas-sensing technology for high-efficiency detection of TEA is of great worth for human health and environmental monitoring. In this work, a mixed potential type TEA sensor was initially developed based on pyrochlore Gd₂Zr₂O₇ solid state electrolyte and BiVO₄ sensing electrode. The sensor generates high response values of - 62.2 mV and - 134.4 mV to 5 ppm and 100 ppm TEA at 500 °C, respectively. The response value of the sensor displays a logarithmic linear relationship with the concentration of TEA in the range of 1-100 ppm with the sensitivity of - 50.8 mV/decade. Besides, the sensor shows good response and recovery characteristics, and the response and recovery time to 10 ppm TEA is 10 s and 89 s, respectively. Moreover, the sensor possesses good humidity resistance, reproducibility and stability. The sensing behavior of the sensor is explained by the mixed potential sensing mechanism, which is confirmed by the measurement of the polarization curves. This work provides a good supplement for TEA gas sensor, which holds important application value for the sensitive detection of TEA in the environment.

TiO2 Gas Sensors Combining Experimental and DFT Calculations: A Review

Gas sensors play an irreplaceable role in industry and life. Different types of gas sensors, including metal-oxide sensors, are developed for different scenarios. Titanium dioxide is widely used in dyes, photocatalysis, and other fields by virtue of its nontoxic and nonhazardous properties, and excellent performance. Additionally, researchers are continuously exploring applications in other fields, such as gas sensors and batteries. The preparation methods include deposition, magnetron sputtering, and electrostatic spinning. As researchers continue to study sensors with the help of modern computers, microcosm simulations have been implemented, opening up new possibilities for research. The combination of simulation and calculation will help us to better grasp the reaction mechanisms, improve the design of gas sensor materials, and better respond to different gas environments. In this paper, the experimental and computational aspects of TiO2 are reviewed, and the future research directions are described.

Gas sensing based on metal-organic frameworks: Concepts, functions, and developments

Effective detection of pollutant gases is vital for protection of natural environment and human health. There is an increasing demand for sensing devices that are equipped with high sensitivity, fast response/recovery speed, and remarkable selectivity. Particularly, attention is given to the designability of sensing materials with porous structures. Among diverse kinds of porous materials, metal-organic frameworks (MOFs) exhibit high porosity, high degree of crystallinity and exceptional chemical activity. Their strong host-guest interactions with guest molecules facilitate the application of MOFs in adsorption, catalysis and sensing systems. In particular, the tailorable framework/composition and potential for post-synthetic modification of MOFs endow them with widely promising application in gas sensing devices. In this review, we outlined the fundamental aspects and applications of MOFs for gas sensors, and discussed various techniques of monitoring gases based on MOFs as functional materials. Insights and perspectives for further challenges faced by MOFs are discussed in the end.

Improved TEA Sensitivity and Selectivity of In2O3 Porous Nanospheres by Modification with Ag Nanoparticles

A highly sensitive and selective detection of volatile organic compounds (VOCs) by using gas sensors based on metal oxide semiconductor (MOS) has attracted increasing interest, but still remains a challenge in gas sensitivity and selectivity. In order to improve the sensitivity and selectivity of In2O3 to triethylamine (TEA), herein, a silver (Ag)-modification strategy is proposed. Ag nanoparticles with a size around 25–30 nm were modified on pre-synthesized In2O3 PNSs via a simple room-temperature chemical reduction method by using NaBH4 as a reductant. The results of gas sensing tests indicate that after functionalization with Ag, the gas sensing performance of In2O3 PNSs for VOCs, especially for TEA, was remarkably improved. At a lower optimal working temperature (OWT) of 300 °C (bare In2O3 sensor: 320 °C), the best Ag/In2O3-2 sensor (Ag/In2O3 PNSs with an optimized Ag content of 2.90 wt%) shows a sensitivity of 116.86/ppm to 1–50 ppm TEA, about 170 times higher than that of bare In2O3 sensor (0.69/ppm). Significantly, the Ag/In2O3-2 sensor can provide a response (Ra/Rg) as high as 5697 to 50 ppm TEA, which is superior to most previous TEA sensors. Besides lower OWT and higher sensitivity, the Ag/In2O3-2 sensor also shows a remarkably improved selectivity to TEA, whose selectivity coefficient (STEA/Sethanol) is as high as 5.30, about 3.3 times higher than that of bare In2O3 (1.59). The sensitization mechanism of Ag on In2O3 is discussed in detail.

Synergistic Effect of Au-PdO Modified Cu-Doped K2W4O13 Nanowires for Dual Selectivity High Performance Gas Sensing

Both 3-hydroxy-2-butanone and triethylamine are highly toxic and harmful to human health, and their chronic inhalation can cause respiratory diseases, eye lesions, dermatitis, headache, dizziness, drowsiness, and even fatality. Developing sensors for detecting such toxic gases with low power consumption, high response with superselectivity, and stability is crucial for healthcare and environmental monitoring. This study presents a typical gas sensor fabricated based on AuPdO modified Cu-doped K₂W₄O₁₃ nanowires, which can selectively detect 3-hydroxy-2-butanone and triethylamine at 120 and 200 °C, respectively. The sensor displays excellent sensing performance at reduced operating temperature, high selectivity, fast response/recovery, and stability, which can be attributed to a synergistic effect of Cu dopants and AuPdO nanoparticles on the K₂W₄O₁₃ host. The enhanced sensing response and selectivity could be attributed to the oxygen vacancies/defects, bandgap excitation, the electronic sensitization, the reversible redox reaction of PdO and Cu, the cocatalytic activity of AuPdO, and Schottky barrier contacts at the interface of tungsten oxide and Au. The significant variations in the activation capacities of Cu-doped K₂W₄O₁₃, Pd/PdO, and Au nanoparticles toward 3H-2B and TEA, and the diffusion depth of the two gases in the coated sensing layer may cause dual selectivity. The designed gas sensor materials can serve as a sensitive target for detecting toxic biomarkers and hold broad application prospects in food and environmental safety inspection.

Semiconductor Gas Sensor for Triethylamine Detection

With the demanding detection of unique toxic gas, semiconductor gas sensors have attracted tremendous attention due to their intriguing features, such as, high sensitivity, online detection, portability, ease of use, and low cost. Triethylamine, a typical gas of volatile organic compounds, is an important raw material for industrial development, but it is also a hazard to human health. This review presents a concise compilation of the advances in triethylamine detection based on chemiresistive sensors. Specifically, the testing system and sensing parameters are described in detail. Besides, the sensing mechanism with characterizing tactics is analyzed. The research status based on various chemiresistive sensors is also surveyed. Finally, the conclusion and challenges, as well as some perspectives toward this area, are presented.

Ultrasensitive ppb-level trimethylamine gas sensor based on p-n heterojunction of Co3O4/WO3

Trace poisonous and harmful gases in the air have been harming and affecting people's health for a long time. At present, effective and accurate detection of ppb-level harmful gas is still a bottleneck to be overcome. Herein, we report a ppb-level triethylamine (TEA) gas sensor based on p-n heterojunction of Co₃O₄/WO₃, which is prepared with ZIF-67 as the precursor and provides Co₃O₄deposited tungsten oxide flower-like structure. Due to the introduction of Co₃O₄and the 3D flower-like structure of WO₃, the Co₃O₄/WO₃-2 gas sensor shows excellent gas sensing performance (1101 for 10 ppm at 240 °C), superb selectivity, good long-term stability and linear response for TEA concentration. Moreover, the experimental results indicate that the Co₃O₄/WO₃-2 gas sensor also possesses a good response to 50 ppb TEA, in fact, the theoretical limit of detection is 0.6 ppb. Co₃O₄not only improves the efficiency of electron separation/transport, but also accelerates the oxidation rate of TEA. This method of synthesizing p-n heterojunction with ZIF as the precursor provides a new idea and method for the preparation of low detection limit gas sensors.

MOF-Derived Mesoporous and Hierarchical Hollow-Structured In2O3-NiO Composites for Enhanced Triethylamine Sensing

It remains a challenge to design and fabricate high-performance gas sensors using metal-organic framework (MOF)-derived metal oxide semiconductors (MOS) as sensing materials due to the structural damage during the annealing process. In this study, the mesoporous In₂O₃-NiO hollow spheres consisting of nanosheets were prepared via a solvothermal reaction and subsequent cation exchange. More importantly, the transformation of Ni-MOF into In/Ni-MOF through exchanging the Ni²⁺ ion with In³⁺ ion can prevent the destruction of the porous reticular skeleton and hierarchical structure of Ni-MOF during calcination. Thus, the mesoporous In₂O₃-NiO hollow composites possess high porosity and large specific surface area (55.5 m² g^-1), which can produce sufficient permeability pathways for volatile organic compound (VOCs) molecules, maximize the active sites, and enhance the capacity of VOC capture. The mesoporous In₂O₃-NiO-based sensors exhibit enhanced triethylamine (TEA) sensing performance (S = 33.9-100 ppm) with distinct selectivity, good long-term stability, and lower detection limit (500 ppb) at 200 °C. These results can be attributed to the mesoporous hollow hierarchical structure and p-n junction of In₂O₃-NiO. The preparation concept mentioned in this work may provide a versatile platform applicable to various mesoporous composite sensing material-based hollow structures.

0D/2D CdS/ZnO composite with n-n heterojunction for efficient detection of triethylamine

It is imperative to seek for novel materials with pronounced gas sensing performance towards triethylamine for the sake of human health. Herein, we successfully fabricate an outstanding triethylamine sensor based on CdS/ZnO composite with 0D/2D structure, which are prepared by in-situ growth of CdS quantum dots on ultra-thin ZnO nanosheets. The ratios between the two ingredients are adjusted and their effect is evaluated. The optimal sample exhibits the lowest operating temperature of 200 °C, the highest response value of ~20 and the fastest response time of 2 s. Besides, it also has the virtues of durable stability, excellent selectivity and superior anti-interference ability. The mechanism behind the aforementioned intriguing performance is investigated by X-ray photoelectron spectroscopy, Kelvin probe and density function theory (DFT) simulation. All the results verify that the enhanced gas sensing properties are derived from splendid 0D/2D structure, n-n heterojunction and large specific surface area. Additionally, this study opens an avenue for designing sensors with 0D/2D structure.