To Triethylamine Research Articles

Rational design of ZnO-SnO2 Janus nanofibers for highly sensitive triethylamine detection

Herein, ZnO-SnO2 Janus nanofibers (NFs) were synthesized by a parallel electrospinning method and its sensing performances were tested. Considering the compositions of the two metal oxide semiconductors in Janus structure, different ratios of ZnO and SnO2 were designed and controlled. The optimum ratios of ZnO and SnO2 was 1:2 by analyzing their sensing performances to triethylamine (TEA) gas. Gas sensors based on ZS-12 Janus NFs exhibited a high response to TEA (45.2) and an excellent sensing response/recovery reproducibility. In order to investigate the sensing mechanism of Janus structure, ZnO NFs and SnO2 NFs were synthesized and used as controlled experiment. The results indicated that the heterostructures in Janus NFs is the key factor for the enhanced TEA sensing performances. The electrons flowed in the ZnO-SnO2 Janus structure leading to the variation of ionic oxygen species and electron depletion layer. These phenomena improved the reaction of TEA gas molecules with ionic oxygen species so that the TEA sensing performances were enhanced. Based on the Janus structures, a satisfactory gas sensor for detecting TEA gas were developed. Significantly, this work investigated the sensing mechanism of Janus structures and provided an efficient strategy for the gas sensing materials.

Highly selective triethylamine gas sensor based on ZnO/Ti3C2Tx MXene self-assembly heterostructure

MXenes, as new two-dimensional transition metal compounds, has become promising sensing materials due to the excellent metal conductivity, abundant adsorption sites and the terminal groups of -O, -OH and -F. In this study, we report the well-etched accordion-like Ti3C2Tx by removing Al layer in Ti3AlC2, where Tx represents a wealth of terminal functional groups (-OH, -F, -O, etc.). In addition, unique hierarchical self-assembly ZnO/Ti3C2Tx nanocomposites are synthesized by hydrothermal method. The Brunauer-Emmett-Teller Method investigation also shows that the ZnO/Ti3C2Tx nanocomposites has a specific surface area of about 22.08 m2/g, and the pore size is mainly located at 11.1 nm. The innovative nanostructure is conducive to the adsorption and response of gas molecules. By investigating the gas sensitive properties of the sensors, it is found that the response of the ZnO/Ti3C2Tx sensor to triethylamine (TEA) is improved by 66 times and 1.58 times over that of pure Ti3C2Tx and ZnO, and the optimal operating temperature is 60℃ lower than that of pure ZnO. In addition, the LOD (Low Of Detection) of about 32.7 ppb indicates that the ZnO/Ti3C2Tx sensor is suitable for the detection of low concentrations TEA. The sensing performances of the ZnO/Ti3C2Tx sensor at a high humidity of 75 % RH verifies the strong sensing performance in high humidity environment. Furthermore, the composite sensor stabilize in 6 repetitive tests and present slight decrease in response value over 30 days. The excellent TEA sensitive properties indicate that the ZnO/Ti3C2Tx nanocomposite sensor may have promising applications in the gas sensitive field.

Site‐Selective MoS2‐Based Sensor for Detection and Discrimination of Triethylamine from Volatile Amines Using Kinetic Analysis and Machine Learning

AbstractDetection and discrimination of volatile organic compounds (VOCs) is important to provide a more realistic assessment of their potential implication in complex environments and medical diagnostics based on volatile biomarkers. Herein, chemiresistive sensors are fabricated using stacked MoS2 nanoflakes with defects and exposed‐edge sites. The sensor is found to be extremely selective to triethylamine (TEA) over polar, non‐polar VOCs and atmospheric gases. The sensor exhibits a sensitivity of 1.72% ppm−1, fast response/recovery (19 s/39 s) to 100 ppm TEA at room temperature, low limit of detection (64 ppb), device reproducibility, humidity tolerance (RH 90%) and stability tested up to 60 days. The kinetic analysis of sensing curves reveals two discrete adsorption sites corresponding to edge and basal sites of interaction, with a higher rate constant of association and dissociation for TEA. The Density Functional Theory (DFT) studies support higher adsorption energy of TEA on MoS2 surface with respect to other volatile amines. The sensor demonstrates TEA recognition and composition estimation capability in a binary mixture of a similar class of VOCs using Machine Learning driven analysis with 95% accuracy. The ability to discriminate amines in binary mixture of other volatile amines paves the way for the advancement of next‐generation devices in the field of disease diagnosis.

Dual enhancement in response and anti-humidity properties of a triethylamine sensor based on trimethoxypropylsilane self-assembled functionalized In2O3

The anti-humidity properties of metal oxide semiconductors have become an important performance index requirement for the commercialization of gas sensors since ambient humidity is inescapable in many situations which changes rapidly depending on the region and climate. Herein, functionalized In2O3 nanospheres with enhanced response value and anti-humidity properties to triethylamine (TEA) were prepared by self-assembly of trimethoxypropylsilane (PTES) on the surface of In2O3. The effect of different levels of PTES functionalization on gas sensing properties was investigated in detail. Furthermore, the PTES-In2O3 sensor exhibited a high response (9.3–100 ppm TEA at 80 RH%), a remarkable relative response (95.6 %), a low theoretical detection limit (920 ppb), and long-term stability. The superior gas sensing properties can be attributed to the hydrophobicity of the alkyl chains in the PTES molecule, and the PTES captures free electrons from In2O3 which widens the electron depletion layer. Therefore, the strategy can be widely applied to construct metal oxide gas sensors with excellent humidity resistance and high gas response properties.

3D porous ZnO microspheres sensitized by Ag quantum dots for highly responsive TEA sensors

The study aims to create a highly responsive gas sensor for TEA. In order to achieve this goal, spherical ZnO with layered structure was synthesized by a simple hydrothermal method. Subsequently, Ag quantum dots (QDs) are precipitated onto the surface of the ZnO microspheres. The ZnO microspheres were analyzed to demonstrate that they are comprised of porous nanosheets measuring roughly 10 μm in diameter. The composite with the optimal mass percentage displayed outstanding sensitivity to triethylamine (TEA), yielding a response of 1223, approximately 90 times higher than that of the pure ZnO sensor. Furthermore, this composite also demonstrated remarkable selectivity towards TEA. The exceptional detection results were achieved due to the catalytic influence of Ag as a precious metal, coupled with the distinctive structure of quantum dots and ZnO materials.

Highly specific and sensitive chromo-fluorogenic detection of sarin, tabun, and mustard gas stimulants: a multianalyte recognition approach.

Nerve agents are the most notorious substances, which can be fatal to an individual because they block the activity of acetylcholinesterase. Fighting against unpredictable terrorist assaults and wars requires the simple and quick detection of chemical warfare agent vapor. In the present contribution, we have introduced a rhodamine-based chemosensor, BDHA, for the detection of nerve gas-mimicking agents diethylchlorophosphate (DCP) and diethylcyanophosphonate (DCNP) and mustard gas-mimicking agent 2-chloroethyl ethyl sulfide (CEES), both in the liquid and vapor phase. Probe BDHA provides the ability for detection by the naked eye in terms of colorimetric and fluorometric changes. It has been revealed that the interaction between nerve agents mimics and probe BDHA facilitates spirolactam ring opening due to the phosphorylation process. Thus, the highly fluorescent and colored species developed while probe BDHA is colorless and non-fluorescent due to the intramolecular spirolactam ring. Moreover, probe BDHA can effectively recognize DCP, DCNP, and CEES in the µM range despite many toxic analytes and could be identified based on the response times and quantum yield values. Inexpensive, easily carried paper strips-based test kits were developed for the quick, on-location solid and vapor phase detection of these mustard gas imitating agents (CEES) and nerve gas mimicking agents (DCP and DCNP) without needing expensive equipment or skilled personnel. More remarkably, the test strips' color and fluorescence can be rapidly restored, exposing them to triethyl amine (TEA) for cyclic use, suggesting a potential application in the real-time identification of chemical warfare agents. To accomplish the on-location application of BDHA, we have experimented with soil samples to find traces of DCP. Therefore, the chromo-fluorogenic probe BDHA is a promising, instantaneous, and on-the-spot monitoring tool for the selective detection of DCP, DCNP, and CEES in the presence of others.

Porous layered ZnFe2O4/ZnO heterostructure for enhanced triethylamine detection

Herein, a composite with heterogeneous porous structure composed of layered ZnFe2O4 grown on porous ZnO sheets (ZnO/ZFO composite) was synthesized by combining facile solvothermal and solution growth methods. The effect of solution growth time on ZnO/ZFO composites morphology was investigated and their gas sensing properties was compared. The result indicated the ZnO/ZFO composites sensors, especially the one with a growth time of 30 min showed significant improved gas sensing performance to triethylamine (TEA) compared with that of pure ZnO sheets, ZnFe2O4 and other ZnO/ZFO composites. Its response value to 100 ppm TEA was as high as 78 at 240 °C with good stability and repeatability, and the detection limit was as low as 0.5 ppm. The synergism of rich heterojunctions, increased oxygen-related vacancy species and porous structure would result in the excellent TEA sensing performance of ZnO/ZFO composite.

Work function analysis of photo-enhanced triethylamine adsorption impact on Au embedded CeO2 coated ZnO hybrid nanostructures: An investigation by scanning kelvin probe

This article utilizes a scanning kelvin probe to examine the impact of visible light and volatile organic compounds (VOCs) on an organic/inorganic/noble metal hybrid sensing layer. ZnO/Poly/CeO2/Poly/Au hybrid nanostructures were prepared on ITO substrate by layer-by-layer coating technique. In this case, PAH and DS polymers act as binders. The assembly of Au nanorods (NRs) on the polymer-coated ZnO NRs incorporated with CeO2 nanoparticles (NPs) and its maximum absorbance in the visible light region were studied by the structural and optical characterizations, respectively. The hybrid sensor's optical properties allowed for sizable changes in contact potential difference (CPD) when exposed to light. Although a non-selective interaction was observed, the increased responsiveness to Triethylamine (TEA) under visible light creates coordination bonds between the hybrid molecules. Notably, the surface charge was tuned in the surface of the sensing layer by varying the surfactant to explore the TEA responsiveness. Intriguingly, ZnO/Poly/CeO2 (+) has demonstrated improved adsorption capability towards TEA under irradiation due to the surface oxygen vacancies compared to ZnO/Poly/CeO2 (-). Also, ZnO/Poly/CeO2 (+) exhibited higher selectivity at adsorbing TEA than either ethanol or n-hexane.

Phase-Dependent Dual Discrimination of MoSe2/MoO3 Composites Toward N,N-Dimethylformamide and Triethylamine at Room Temperature.

Herein, we present, a chemiresistive-type gas sensor composed of two-dimensional 1T-2H phase MoSe2 and MoO3. Mixed phase MoSe2 and MoSe2/MoO3 composites were synthesized via a facile hydrothermal method. The structure analysis using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy revealed the formation of different phases of MoSe2 at different temperatures. With increase in synthesis temperature from 180 to 200 °C, the relative percentage of 1T and 2H-MoSe2 phases changed from 80 to 48%. On the other hand, at 220 °C, 2H-MoSe2 was obtained as a major component. The gas sensing properties of individual MoSe2 and composites were investigated at room temperature toward various analytes. The obtained results revealed that composites possess improved sensing features as compared with individual MoSe2 or MoO3. Data also revealed that the composite with dominating 1T-phase exhibits relatively higher response (10%, at 10 ppm) for dimethylformamide (DMF) compared to triethylamine (TEA) (3%, at 10 ppm). In contrast, the composite with larger 2H-phase exhibited affinity toward TEA and had a relative response of about 2%. Therefore, selectivity of a sensor device can be tuned by an appropriately designed MoSe2/MoO3 composite. These results signify the importance of MoO3-based composites with dual-phase MoSe2 for successfully discriminating between DMF and TEA at room-temperature.

Novel salicylic acid derivatives connecting to five-membered cycle through an acyl hydrazone bond as multi-stimuli responsive fluorescent smart materials with photoswitching properties

In order to exploit novel multi-stimuli responsive fluorescent materials, a series of novel fluorescent molecules of salicylic acid derivatives were designed and synthesized via introducing pyrazole or cyclopentane to the salicylic acid scaffold through a special Schiff base–acylhydrazone, and the molecular structures of representative compounds A2 and A4 were verified via single crystal X–ray diffraction. All title molecules could exhibit obvious solvatofluorochromism from cyan to indigo in several solutions with different polarity. The fluorescence titration data exhibited compound A2 and complex A2-Cu2+ with prime detection limits to Cu2+ (0.24 μM) and S2- ions (2.83 μM). The sensitive recognition of A2 to trifluoroacetic (TFA) and A2-TFA to triethylamine (TEA) were also confirmed via fluorescent titration experiments in various solutions, respectively. What’s more, the 1H NMR and UV/Vis absorption spectra further explained the mechanism between molecules and ions or molecules and TFA/TEA. Besides, the photoswitching properties of the compounds A2 and A3 could be demonstrated via the irradiation of special wavelength light or heating accompanied with changes in quantum yields. In addition, these phenomena of multiple responses were explained via Density Functional Theory (DFT) based on the Gaussian calculations. Thus, this work provided a preliminary basis for the research of multi-stimuli responsive fluorescent molecules with photoswitching properties.

LaMnO3/Co3O4 nanocomposite for enhanced triethylamine sensing properties

LaMnO3 modified Co3O4 nanocomposites were prepared by simple hydrothermal method combined with sol–gel method. The gas sensitivity properties of pure Co3O4 and LaMnO3/Co3O4 with different composite proportions are compared. It is found that 0.6-LMO/Co3O4 sensor has higher sensitivity to triethylamine (TEA) than pure Co3O4 sensor, which is improved by 9.27 times. And the working temperature is reduced from 150 to 130 °C. Besides, it has excellent gas selectivity and repeatability. The improvement of the gas sensitivity of LaMnO3/Co3O4 sensor may be due to the fact that LaMnO3 is an effective catalyst, and the catalytic performance perhaps is beneficial to improving the sensing performance. In addition, the formation of p–p heterojunctions may be the key factor to improve the gas sensing performance. This work provides a new Co3O4-based gas sensing material for the detection of TEA.

Biotemplate synthesis of a Co3O4 microtube sensor for fast triethylamine detection.

A low operating temperature and short response/recovery time are essential factors for sensors. Hence, it is necessary to create a sensor that can quickly detect target gas at a relatively low temperature. In this work, Co3O4 microtube based sensors were fabricated by a bio-template method using absorbent cotton. Co3O4 microtube sensors prepared in different concentrations of a salt solution displayed different sensitivities to triethylamine (TEA). The Co3O4-0.10 microtube sensor exhibited excellent sensitivity to TEA at 160 °C. The response of the Co3O4-0.10 sensor to 100 ppm TEA gas was 31.27 and the detection limit of TEA was 50 ppb. Meanwhile, the Co3O4-0.10 sensor also showed a short response/recovery time, such as 95 s/38 s to 100 ppm TEA, high selectivity, a good linear relationship (R2 = 0.994 for 1-100 ppm TEA and R2 = 0.991 for 50-1000 ppb TEA gas), fine repeatability and long-term stability, and strong humidity resistance. Thus, Co3O4 microtube based sensors prepared using a bio-template method have potential application prospects for the detection of TEA gas.

An enhanced triethylamine response by incorporating mesoporous CuO into nanosheet-assembled Co3O4 microtubes

Realizing high gas response to triethylamine (TEA) are desirable for employment of sensors in applications of industrial safety and assessing the freshness of the seafood. Herein, a CuO/Co3O4 heteojunction is proposed to improve the gas response performance via incorporating mesoporous CuO into nanosheet-assembled Co3O4 microtubes. A novel approach to generate different proportion mesoporous CuO/Co3O4 heterojunction is demonstrated, through which the morphologies can be fine-tuned. The resultant gas sensing performance shows that the Cu-Co-2 specimen exhibits the remarkably enhanced gas response value (7.6) to 200 ppm TEA, wide linear detection range (1–200 ppm), excellent repeatability and long-term stability as well as good gas selectivity to TEA gas at the working temperature of 320 ℃, which can be attributed to the surface active sites and the CuO/Co3O4 heterointerface. This facile approach sheds lights on the design of sensing materials via construction of heterostructures for the high efficiency detection of target gas.

Co9S8@In2S3 hetero-nanostructures as highly sensitive and selective triethylamine sensor

Using Cobalt 2-methylimidazole (ZIF-67) as the precursor, Co9S8/In2S3 was successfully synthesized. The characteristic structure of Co9S8/In2S3 is Co Metal-Organic framework (Co-MOF). Co9S8/In2S3 semiconductor material was prepared by the hydrothermal method, which presented a special multi-wrinkled flower-like morphology. The Co9S8/In2S3 semiconductor material has selectivity and high sensitivity to triethylamine (Rair/Rgas=100.3, 20 ppm), ultra-low detection limit (100 ppb), and good linearity relation at working temperature of 300 °C. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The growth mechanism of these products was proposed. A possible mechanism to explain the high sensing properties of these morphologies was that the Co9S8/In2S3 material had p-n heterojunction structure characteristics, coupled with its high porosity and specific surface area on the morphology helped to improve the sensitivity to triethylamine (TEA).

Triethylamine Gas Sensors Based on BiOBr Microflowers Decorated with ZnO Nanocrystals

In this work, ZnO nanocrystals (NCs) are innovatively decorated on the hierarchically porous microflowers (MFs) of BiOBr. The preparation is accompanied by the construction of n–n nano-heterojunctions. The crystallographic information, microstructure, oxygen vacancy, and gas sensing performances of BiOBr/ZnO composites are investigated. The BiOBr/ZnO sensor presents excellent response characteristics to triethylamine (TEA). Compared with BiOBr MFs and pure ZnO NCs, the BiOBr/ZnO composite sensor exhibits a higher response (Ra/Rg) of about 20.57 to 100 ppm TEA at 200 °C. The sensor also shows good selectivity and durable long-term stability, besides the low detection limit of 112 ppb. Even more appealingly, the response time is only 4 s. The improved TEA sensing performance of BiOBr MFs modified with ZnO NCs can be mainly attributed to the unique hierarchical heterogeneous microstructure. Furthermore, the construction of n–n BiOBr/ZnO heterostructures leads to a large specific surface area and effective electron transport, which facilitate the surface reaction and diffusion of TEA molecules. The BiOBr/ZnO composite sensor based on n–n nano-heterojunctions may provide a valuable strategy for the detection of volatile organic compounds.

Preparation and TEA gas sensing properties of Pt-modified honeycomb-like porous SnO2 nanosheets

In this paper, honeycomb-like porous Pt-modified SnO2 nanocomposites were synthesized via a two-step method. The three-dimensional (3D) hierarchical porous structure was assembled from numerous SnO2 nanosheets with an average thickness of 16 nm. The gas sensing performance of the sensors based on pristine SnO2 and Pt/SnO2 nanocomposites was systematically investigated. The results indicated that decorating of Pt nanoparticles could significantly improve the sensitivity of SnO2 sensors to triethylamine (TEA), but could also reduce the optimal working temperature from 250 °C to 200 °C. In particular, the Pt/SnO2 based sensor with a Pt content of 1 at% exhibited the maximum response value, shortest response time, and excellent stability, implying its great application prospect for TEA detection. The significant improvement of TEA sensing performance of Pt-modified SnO2 sensors were attributed to the unique hierarchical porous structure and sensitizing actions of Pt nanoparticles.

Surface oxygen vacancies actuated MoO3/CuMoO4 self-assembled microspheres for highly selective triethylamine detection

The construction of tunable oxygen vacancies on the surface of materials has become an emerging approach to develop excellent gas sensitivity, in spite of the critical need for the influencing mechanism. In this paper, novel MoO3/CuMoO4 self-assembled microspheres with superior gas-sensing performance to triethylamine (TEA) have been fabricated by a simple solvothermal route. The introduction of Cu2+ plays a key role for the surface defects and morphological evolution of MoO3-based composites. The sensors based on MoO3/CuMoO4 microspheres exhibit an optimal response of 240.1 toward 100 ppm TEA with fast response and recovery time (45/15 s) at a low operating temperature of 300 °C, together with the low detection limit of 500 ppb, good long-term stability and reliability, and remarkable selectivity for TEA. Actually, abundant oxygen vacancies as active sites greatly contribute to the increasing surface chemisorbed oxygen. The enhanced gas-sensing mechanism can be mainly ascribed from the combination of the formation of MoO3-CuMoO4 heterojunctions, surface oxygen vacancies, and the self-assembled microstructure for the improved electron transfer behavior. The present work provides a new insight into the design of surface oxygen vacancies actuated gas sensors with unique surface/interface reactive process and transport mechanism.

Enhanced surface electron migration of porous and hollow SnO2/Zn2SnO4 heterostructures for efficient triethylamine-sensing performance

Porous and hollow SnO2/Zn2SnO4 composites with typical one-dimensional (1D) structure have been synthesized by adjusting the amounts of 2-methylimidazole zinc salt (ZIF-8) added in the precursor solution through a modified electrospinning technology. Compared with the gas-sensing performance of different samples detected in the normal condition, it is confirmed that the optimal working temperature can be markedly decreased from 260 to 120 °C under UV light irradiation, along with the substantially improved gas selectivity. In addition, SnO2/Zn2SnO4 heterostructures exhibit a higher response (increases from 1.7 to 2.8) and faster response/recovery times (decreases from 24/154 to 14/42 s) to triethylamine (TEA) than that of the pure SnO2. Significantly, the good practicality of gas sensors for food spoilage evaluation could be testified by effectively detecting the gas released during the putridity of prawns. UV light enhanced surface electron migration mainly contributes to the elevated synergistic effect between the formation of n-n heterojunction and tunable surface/interface electron transport behavior, as well as the adsorption and desorption of TEA molecules on the surface of the sensing materials.

Influence of gas adsorption on the surface photovoltage of Au nanorods embedded polymer coated ZnO nanorods under visible light irradiation

The synergism between the photosensitivity and gas sensitivity enabled the development of low powered highly selective gas sensors. In particular, organic/inorganic hybrid materials contribute to the coupling effect of light activated surface photovoltage modifications. In this report, the effect of visible light and volatile organic compounds (VOCs) on the hybrid sensing layer involving organic/inorganic/noble metal through scanning kelvin probe was disseminated. The sensor was fabricated by spin coating the layer-by-layer assembled poly (allylamine hydrochloride) (PAH) and dextran sulfate (DS) on hydrothermally grown ZnO nanorods followed by the incorporation of gold nanorods on ITO substrates. Structural and optical characterizations revealed the assembly of Au nanorods on the polymer coated ZnO nanorods and maximum absorbance in the visible light region, respectively. The optical nature of the hybrid sensor facilitated significant changes in contact potential difference (CPD) when irradiated with light. Changes in CPD values were measured with respect to alcohol, alkane and amine under illumination. A non-selective interaction was observed, yet the enhanced visible light response to triethylamine (TEA) corresponds to the formation of coordination bonds between the hybrid sensor and adsorbed species. The potential shift of ∼31 mV, ∼67 mV and ∼164 mV were observed for TEA by ZnO, ZnO/Poly and ZnO/Poly/Au, respectively. The simultaneous charge transfer/separation ability, surface plasmon resonance and inhibition of recombination of photogenerted carriers by Au promoted the interaction. Evidence of selective interaction can be elucidated through the selection of different VOCs under specific type of gas for CPD measurements.

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.