Ppm Acetone Research Articles

Enhanced acetone detection performance of mechanically-mixed WO3:ZnO composites

In recent years, the potential use of mixed metal oxide WO3:ZnO is widely sought in photocatalytic application due to its excellent electrical and optical properties, but is less explored for chemiresistive sensor. The heterojunction effect in WO3:ZnO is of particular interest to eradicate common issues suffered by the pristine metal oxide sensors, such as limited sensitivity, poor selectivity, and high operating temperature. In addition, the acetone detection study based on heterostructured WO3:ZnO is quite limited. Herein, we demonstrate that the mechanically-mixed WO3:ZnO sensor exhibits comparable reducing gas sensing performance as other doped WO3:ZnO and relative improvement compared with the undoped composites, without the need of catalyst. In this work, WO3:ZnO thin-film based chemiresistive sensors were fabricated through straightforward methods comprising mechanical mixing and drop casting of sensor materials onto gold interdigitated alumina substrates. Structural and morphological properties of the prepared WO3, ZnO, and WO3:ZnO composites were examined through the X-ray diffraction (XRD), Raman spectroscopy, photoluminescence spectroscopy (PL), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDX) analyses, respectively. Sensor performance parameters including operating temperature and response were determined. The sensing properties of WO3:ZnO composites with different weight compositions (1:1, 1:2, and 1:3) were evaluated against the pristine ZnO and WO3. The weight ratio of 1:2 was the optimal composition for the WO3:ZnO composite to achieve the highest sensor response of 53.8 % towards 300 ppm acetone at 200 ºC compared to the pristine ZnO with a response of 23.5 %. The WO3:ZnO (1:2) thin film displayed granular morphology with uniform particle dispersion and porosity, enhancing the gas diffusion. The WO3:ZnO (1:2) thin-film composite sensor exhibited improved sensing performance and good repeatability towards acetone compared with that of ZnO and WO3. The enhanced response to acetone was possibly contributed by the development of n-n heterojunctions, porous morphology, and surface defects in the WO3:ZnO composite. The underlying sensing mechanism of WO3:ZnO composite is also discussed extensively with the aid of energy band diagrams. This study presents a foundation for future development of cost-effective acetone sensors through mechanical mixing with great potential for practical and scalable implementation in various industries.

MXene (Ti3C2Tx)/Rh-doped SnO2 composites for improved acetone sensing properties

Rh-doped SnO2 nanofibers have demonstrated high selectivity and response in detecting acetone. However, these nanofibers operated at high temperature and exhibited a long recovery time. In this study, a two-dimensional material MXene was introduced into Rh-doped SnO2 nanofibers, and MXene (Ti3C2Tx)/Rh–SnO2 composites were synthesized via hydrothermal method. The morphology, structure and composition of MXene (Ti3C2Tx)/Rh–SnO2 were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller techniques (BET). The results indicated that MXene (Ti3C2Tx)/Rh–SnO2 composites formed compact heterostructures. The effects of adding different volumes (0.5, 1, 1.5, and 2 ml) of 5 mg/ml MXene on the sensing properties of the composites were investigated. The sensing results showed that the composite of (1 ml) MXene (Ti3C2Tx)/Rh–SnO2 achieved a response as high as 82.46 % to 100 ppm acetone gas at 100 °C and exhibited rapid response and recovery times of 3/8 s, compared to the optimal operating temperature (190 °C) and recovery time (43 s) observed with the pristine Rh-doped SnO2 nanofibers, there is a significant improvement. It also demonstrated outstanding humidity resistance and a minimum detection limit of 0.6 ppm. Moreover, the addition of MXene not only significantly affects the sensing performance of the pristine Rh-doped SnO2 nanofibers but also preserves its sensing advantages. The sensing mechanism of the MXene (Ti3C2Tx)/Rh–SnO2 composites is also discussed. Herein, MXene (Ti3C2Tx)/Rh–SnO2 composites presents a feasible strategy for enhancing the sensing properties of gas sensors.

Synthesis of ZnO@Fe2O3 microflowers with enhanced performance in volatile organic compound detection

Metal-oxide semiconductor is widely applied in gas sensor for volatile organic compound detection. However, these sensors usually exhibit poor selectivity and inferior sensitivity. Here, ZnO@Fe2O3 microflowers were synthesized using FeOOH microflowers as precursors via a simple solution reaction route, followed by heat treatment. The ZnO@Fe2O3 microflowers were characterized using a series of techniques, and their sensing responses to volatile organic compounds (VOCs) were evaluated in comparison with those of pristine Fe2O3. The ZnO@Fe2O3 microflower sensor exhibited better responses to several gases, especially acetone, with a response of 74.3 towards 100 ppm acetone, which is 2.85 times higher than that of the Fe2O3 microflower sensor. The sensor also presented high selectivity, reproducibility, and stability in sensing different VOCs. The large specific surface area, heterostructure, favorable hierarchical flower-like nanostructure assembled by the nanosheets, and high porosity of the ZnO@Fe2O3 microflowers contributed to its enhanced gas-sensing responses. Overall, this synthetic strategy for fabricating flower-like ZnO@Fe2O3 nanostructures can be widely applied.

A highly responsive, moisture resistant diabetes diagnostic gas sensor with Pt-loaded porous GO/ZnO

Achieving high response of metal-semiconductor oxide gas sensors in humid environment is a collective goal of the scientific community. Herein, a gas sensor based on porous graphene oxide (GO) and zinc oxide (ZnO) composite (PGZ) decorated by Pt catalysts is presented for valid acetone detection with high moisture resistance. By deposit Pt nanoparticles on the surface of PGZ to form Pt/PGZ, its responsiveness and moisture resistance are both further improved. The Pt/PGZ sensor with optimized Pt (Pt 200/PGZ) loading displays a response of 150.2 acetone at 220 °C for 50 ppm acetone, which is nearly 3.5 times than PGZ composite (42.9). In addition, the Pt/PGZ gas sensor has a high response (Ra/Rg=44.5) even at 90 % relative humidity of 50 ppm acetone. It also has excellent stability (less than 5 % fluctuation for 10 cycle responses and 8 weeks intermittent tests) and fast response/recovery time (4 s/7 s). Herein offers a new strategy for achieving high response of gas sensors in high humidity environments.

YSZ-based mixed-potential acetone sensor with LaBaCo2O5+δ sensitive electrode for diabetic diagnosis

The acetone concentration in exhaled breath can be utilized for the noninvasive diagnosis of diabetes. In this study, to fulfil the requirements of breath analysis for diabetes diagnosis, high-performance mixed-potential acetone sensors based on yttria-stabilized zirconia were successfully developed by employing a novel sensitive electrode (SE) material, namely, LaBaCo2O5+δ. Electrochemical measurement results revealed that the LaBaCo2O5+δ SE, sintered at 1000 ℃, exhibited outstanding electrochemical catalytic activity toward acetone. The device incorporating this SE demonstrated a peak response of −46 mV to 100 ppm acetone at 655 ℃. Sensitive performance assessments indicated the capability of the sensor to detect acetone concentrations ranging from 200 ppb to 100 ppm. Based on the mixed-potential model, the sensitivities of the current device were quantified as −1.3 and −53.7 mV/decade within the acetone concentration ranges of 0.2−5 and 10−100 ppm, respectively. Furthermore, the fabricated sensor exhibited exceptional selectivity, repeatability, humidity resistance, and long-term stability. In addition, simulated expiratory experiments showed that the developed sensor has substantial potential for application in breath analysis for diabetes diagnosis and noninvasive monitoring of a patient’s physical status.

Femtosecond Laser Ionization Mass Spectrometry for Online Analysis of Human Exhaled Breath.

A variety of organic compounds in human exhaled breath were measured online by mass spectrometry using the fifth (206 nm) and fourth (257 nm) harmonic emissions of a femtosecond ytterbium (Yb) laser as the ionization source. Molecular ions were enhanced significantly by means of resonance-enhanced, two-color, two-photon ionization, which was useful for discrimination of analytes against the background. The limit of detection was 0.15 ppm for acetone in air. The concentration of acetone in exhaled breath was determined for three subjects to average 0.31 ppm, which lies within the range of normal healthy subjects and is appreciably lower than the range for patients with diabetes mellitus. Many other constituents, which could be assigned to acetaldehyde, ethanol, isoprene, phenol, octane, ethyl butanoate, indole, octanol, etc., were observed in the exhaled air. Therefore, the present approach shows potential for use in the online analysis of diabetes mellitus and also for the diagnosis of various diseases, such as COVID-19 and cancers.

Enhanced acetone gas sensors based on Pt-modified Co3O4/CoMoO4 heterojunctions

The focus of this work is to develop a sensitive and reliable acetone gas sensor using the Pt-modified Co3O4/CoMoO4 heterojunction derived from metal-organic frameworks (MOFs). Pt-loaded Co3O4/CoMoO4 heterojunction was successfully prepared by the surface redox method, and the composites exhibited high sensitivity and selectivity for acetone with a low detection limit. By modifying the Co3O4/CoMoO4 material with platinum loading, the sensor achieved a response of 24.12 to 20 ppm acetone, which was significantly better than that of the pure Co3O4/CoMoO4 heterojunction. This work not only improves acetone detection strategies, but also enhances the potential for industrial and medical VOC monitoring applications.

Synthesis of self-assembled spherical ZnFe2O4 nanomaterials by the premixed stagnation flame method for highly sensitive acetone sensor

The efficient and reliable detection of acetone is critical for industrial safety, environmental monitoring, and human health. Separately, ZnFe2O4 particles were synthesized by using the premixed stagnation flame method and the co-precipitation method. The premixed stagnation flame method was used to create self-assembled spherical ZnFe2O4 nanoparticles with uniform morphology, polycrystalline morphology, and excellent phase purity. The effect of the gas-sensitive performance of these sensors for two routes on acetone vapor was compared. The sensor synthesized using the premixed stagnation flame method had a response value of up to 26 at 235°C for 100 ppm acetone vapor. It revealed outstanding reproducibility, stability, and selectivity for acetone vapor, which is attributed to the 10 nm "lychee-like" particle structure uniformly dispersed on the surface of the 400–500 nm spherical particles, forming a unique self-assembled structure. The self-assembled spherical structure has a large specific surface area, abundant oxygen adsorption, and oxygen vacancies, which effectively increases the reaction sites and electron mobility inside and outside the nanoparticles. The premixed stagnation flame method of producing spherical ZnFe2O4 nanoparticles presents a viable method for developing extremely sensitive, fast-responding, and selective acetone vapor sensors.

Selectivity towards xylene and ethylbenzene detection induced by synergistic effects of Sm3+ and Yb3+ on p-n heterostructure nanorods of Co3O4-In2O3

The synergistic effects of Sm3+/Yb3+ on a p-n ternary heterostructure of Co3O4-In2O3 (Co-In) nanorods, prepared by a hydrothermal approach for the construction of a gas sensor with unique sensing characteristics are reported. The intrinsic characteristics of the ternary heterostructures, such as surface adsorption states, crystal structures, and chemical states, were analyzed. The sensing analyses demonstrated that amongst the Sm3+/Yb3+ incorporated in the Co-In surface, the Co-In 0.25 mol.% Sm3+ displayed superior gas sensing toward ethylbenzene gas at a low operational temperature (i.e., 75 °C). At 100 °C, the precise selectivity toward xylene vapour was witnessed for the Co-In: 0.25 mol.% YbO. At lower gas concentration ranges of 0.08–5 ppm of acetone, 0.5–5 ppm of benzene, and 5–10 ppm of toluene, ethylbenzene, and xylene, the Co-In: 0.25 mol.% YbO was more sensitive to 0.08 ppm of acetone at 75 °C. Collective materials characterization and testing of the device analyses demonstrated that the observed sensing enhancement is primarily ascribed to the stronger capacity of oxygen-adsorption on Co-In: 0.25 mol.%:YbO. The depletion layer width strongly increased due to the formation of the multi-ternary junctions between the Co3O4, In2O3, and Yb2O3. The VO-rich Co3O4 has favoured the adsorption of xylene. The lower detection of acetone at ppb was associated with the preferred facet of acetone detection in comparison to xylene. The prospective sensing mechanism of the ternary heterostructure-based sensors has also been proposed.

Room temperature acetone gas sensing performance of ZnS-NiO nanocomposite sensor enhanced by UV activation for diabetes detection

Metal oxide semiconductors are popular in gas sensor applications.Current metal oxide-based acetone sensors struggle to deliver ppb-level acetone sensing at low temperatures for biological use. This study synthesizes 4mol% ZnS combined with NiO for acetone sensing. Nanoparticles were studied using FE-SEM, XPS, XRD, and UV-Vis spectroscopy. Mixed ZnS and NiO resulted in rapid gas channel movement and n-p heterojunction development, which increased acetone sensitivity. ZnS-NiO showed a gas sensing response of 163% for 20 ppm acetone at room temperature under UV irradiation, which is 2.3 times higher than pristine NiO (70% at 180 ∘C). ZnS improves sensor selectivity. Heterojunction sensor reaction and recovery times were 20 and 14 seconds, respectively. The composite sensor detection limit was 0.1 ppm. The increased sensitivity validates the n-p heterojunction. The sensor’s higher response values and lower detection limit point to breath analyzer applications such as diabetes detection.

Fe2TiO5 nanoparticle-based novel gas sensor with high response to ethanol and acetone

This paper presents a novel Fe2TiO5 sensing material for ethanol and acetone detection. Pure Fe2TiO5 nanomaterial was synthesized by a combined solvothermal and calcination method using ferrous sulfate as precursor and urea as a surfactant. The microstructure and surface morphology indicate that Fe2TiO5 belongs to the orthorhombic crystal structure with a Bbmm space group and is composed of loose aggregates of irregular nanoparticles (20–30nm) and abundant pores. X-ray photoelectron spectroscopy analysis indicates that the Fe2TiO5 aggregates contain mixed valence states of Fe2+ and Fe3+ and abundant oxygen vacancies. Examination of gas sensing properties suggests that Fe2TiO5 is an excellent gas-sensitive material. Particularly, at a low optimum operating temperature (240 °C), the gas response of the Fe2TiO5 aggregates to 100 ppm ethanol and acetone is as high as 84.1 and 220.9, respectively. The linear relationship between log(S-1) and logC indicates that Fe2TiO5 can accurately detect ethanol and acetone over a wide concentration range. The gas-sensing performance of the novel Fe2TiO5 nanomaterial can be explained based on the synergistic effect of oxygen vacancy defects and the characteristic surface morphology.

Electrophoretically fabricated tubular Taguchi type ZnFe2O4-based thick film gas sensor

A facile method has been developed to fabricate tubular chemi-resistive type thick film gas sensors. The method includes the preparation of a stable suspension of the sensing material followed by fabrication of a uniform sensing layer by electrophoretic deposition (EPD) technique on the tubular Taguchi type alumina sensing element. Prior to fabrication of the sensing film, the non-conducting alumina tube is in-situ coated with a conducting polymer (polypyrrole). EPD grown Taguchi sensors demonstrate excellent sensing capability, with responses of 87 % and 46 % to 400 and 12.5 ppm acetone, respectively. Moreover, these sensors exhibit an impressive fast response time of approximately 20–30 s. The developed process can be extended to various other sensing materials to develop Taguchi type sensors in a repetitive manner.

Construction of mesoporous silica-implanted tungsten oxides for selective acetone gas sensing

As a key biomarker for noninvasive diagnosis of diabetes, the selective detection of trace acetone in exhaled gas using a portable and low-cost device remains a great challenge. Semiconductor metal oxide (SMO) based gas sensors have drawn signification attention due to their potential in miniaturization, user-friendliness, high cost-effectiveness and selective real-time detection for noninvasive clinical diagnosis. Herein, we propose a one-pot solvent evaporation induced tricomponent co-assembly strategy to design a novel ordered mesoporous SMO of silica-implanted WO3 (SiO2/WO3) as sensing materials for trace acetone detection. The controlled co-assembly of silicon and tungsten precursors and amphiphilic diblock copolymer poly(ethylene oxide)-block-polystyrene (PEO-b-PS), and the subsequent thermal treatment enable the local lattice disorder of WO3 induced by the amorphous silica and the formation of ordered mesoporous SiO2/WO3 hybrid walls with a unique metastable ε-phase WO3 framework. The obtained mesoporous SiO2/WO3 composites possess highly crystalline framework with large uniform pore size (12.0–13.3 nm), high surface area (99–113 m2/g) and pore volume (0.17–0.23 cm3/g). Typically, the as-fabricated gas sensor based on mesoporous 2.5 %SiO2/WO3 exhibits rapid response/recovery rate (5/17 s), superior sensitivity (Rair/Rgas = 105 for 50 ppm acetone), as well as high selectivity towards acetone. The limit of detection is as low as 0.25 ppm, which is considerably lower than the thresh value of acetone concentration (>1.1 ppm) in the exhaled breath of diabetic patients, demonstrating its great prospect in real-time monitoring in diabetes diagnosis. Moreover, the mesoporous 2.5 %SiO2/WO3 sensor is integrated into a wireless sensing module connected to a smart phone, providing a convenient real-time detection of acetone.

Multiarray Gas Sensors Using Ternary Combined Ti3C2Tx MXene-Based Nanocomposites.

This paper reports chemiresistive multiarray gas sensors through the synthesized ternary nanocomposites, using a one-pot method to integrate two-dimensional MXene (Ti3C2Tx) with Ti-doped WO3 (Ti-WO3/Ti3C2Tx) and Ti3C2Tx with Pd-doped SnO2 (Pd-SnO2/Ti3C2Tx). The gas sensors based on Ti-WO3/Ti3C2Tx and Pd-SnO2/Ti3C2Tx exhibit exceptional sensitivity, particularly in detecting 70% at 1 ppm acetone and 91.1% at 1 ppm of H2S. Notably, our sensors demonstrate a remarkable sensing performance in the low-ppb range for acetone and H2S. Specifically, the Ti-WO3/Ti3C2Tx sensor demonstrates a detection limit of 0.035 ppb for acetone, and the Pd-SnO2/Ti3C2Tx sensor shows 0.116 ppb for H2S. Simultaneous measurements with Ti-WO3/Ti3C2Tx- and Pd-SnO2/Ti3C2Tx-based sensors enable the evaluation of both the concentration and type of unknown target gases, such as acetone or H2S. Furthermore, density functional theory calculations are performed to clarify the role of Ti and Pd doping in enhancing the performance of Ti-WO3/Ti3C2Tx and Pd-SnO2/Ti3C2Tx nanocomposites. Theoretical simulations contribute to a deeper understanding of the doping effects, providing essential insights into the mechanisms underlying the enhanced gas response of the gas sensors. Overall, this work provides valuable insights into the gas-sensing mechanisms and introduces a novel approach for high-performance multiarray gas sensing.

Surface oxygen vacancy adjustment and acetone sensing performance enhancement of ZIF-67 derived Co3O4 with trace Ni-doping

The adjustment of surface oxygen vacancy was realized by doping the trace Ni element into the lattice of ZIF-67 derived Co3O4. The material characterizations indicated that ZIF-67 derived Co3O4 samples have porous square structure and the trace Ni elements successfully enter the lattice of Co3O4 crystal. Because of the increased oxygen vacancies caused by Ni-doping, the content of oxygen species chemically adsorbed on the surface of the optimized sample increased by 12.14 %. Compare with the pure Co3O4, the optimum operating temperatures of all the samples with trace Ni-doping were reduced by 20 °C. The response to 50 ppm acetone of the optimized sample was 30.02 with good selectivity and stability, and the response was 1.67 times higher than that of the pure one. The response-recovery rate was also improved. The response and recovery time of the optimized sample were 38 s and 35 s less than that of the pure one. The influences of oxygen vacancy and Co2+ were analyzed to understand the mechanism of the enhanced sensing properties.

Yolk-shell microspheres perovskite Gd/Fe oxides with rich oxygen vacancies for ultra-sensitive properties in acetone detection

Acetone as a toxic and hazardous gas is widely appeared in life. In this paper, p-type Gd/Fe oxide yolk-shell microspheres were prepared by a one-step hydrothermal method. Characterization and test results shows that perovskite Gd/Fe oxides with yolk-shell microspheres possess abundant oxygen vacancies, which presents excellent acetone gas-sensitive performance. Among the obtained sensor, the optimal operating temperature of the S-4 (Gd0.77/Fe) sensor is reduced to 200 ℃, and the response value (S = 20) to 100 ppm acetone is improved by 5 times (compare to S-1). The lowest detection limit can be as low as 0.5 ppm, furthermore the sensor presents resist-humidity. Electron paramagnetic resonance (EPR) and x-ray photoelectron spectroscopy (XPS) results reveal that the ratio of Gd/Fe has a strong correlation with the content of oxygen vacancies. The rich oxygen vacancies control theory is the main reason for improving gas sensing performance in this work. The presence of oxygen vacancies effectively increases the active sites and further promotes intermolecular interactions. Overall, the sensor S-4 (Gd0.77/Fe) has an important potential in the detection of acetone in human breath with high response and low detection limit under high humidity environment.

Long-term, rapid and stable acetone gas sensing performance of porous rGO/flower-shaped ZnO nanocomposites with a hydrothermal synthesis method

It is prominent and imperative to synthesize gas-sensitive materials using energy-efficient and environmentally friendly methods to enhance their properties. The current paper employs hydrothermal method porous reduced graphene oxide (P-rGO) and zinc oxide (ZnO) with flower-like structure complexes (PGZ) to detect the acetone gas. The gas sensitivity of the PGZ sensor demonstrate a response of 30.38 for 50 ppm acetone, accompanied by a rapid response recovery time of 5 s/7 s at operating temperature of 240 °C. Moreover, the remarkable long-term stability (<15 % fluctuation over 9 cyclic response cycles and 7 weeks of intermittent testing) of the PGZ gas sensor ensures its suitability for practical applications. The P-rGO enlarges the specific surface area of the material, which is conducive to accelerating the electron transfer in the reaction as well as the adsorption and desorption of the target gas, resulting in a rapid response recovery time. The porous structure can also effectively inhibit the agglomeration and growth of ZnO nanoparticles, thus improving long-term stability. Consequently, our study provides a new strategy for the application of 2D materials in gas sensing.

α-Fe2O3/TiO2/Ti3C2Tx Nanocomposites for Enhanced Acetone Gas Sensors.

Metal oxide semi-conductors are widely applied in various fields due to their low cost, easy processing, and good compatibility with microelectronic technology. In this study, ternary α-Fe2O3/TiO2/Ti3C2Tx nanocomposites were prepared via simple hydrothermal and annealing treatments. The composition, morphology, and crystal structure of the samples were studied using XPS, SEM, EDS, XRD, and multiple other testing methods. The gas-sensing measurement results suggest that the response value (34.66) of the F/M-3 sensor is 3.5 times higher than the pure α-Fe2O3 sensor (9.78) around 100 ppm acetone at 220°C, with a rapid response and recovery time (10/7 s). Furthermore, the sensors have an ultra-low detection limit (0.1 ppm acetone), excellent selectivity, and long-term stability. The improved sensitivity of the composites is mainly attributed to their excellent metal conductivity, the unique two-dimensional layered structure of Ti3C2Tx, and the heterojunction formed between the nanocomposite materials. This research paves a new route for the preparation of MXene derivatives and metal oxide nanocomposites.

Oxygen Vacancy-Rich Bimetallic Au@Pt Core-Shell Nanosphere-Functionalized Electrospun ZnFe2O4 Nanofibers for Chemiresistive Breath Acetone Detection.

Sensitive and selective acetone detection is of great significance in the fields of environmental protection, industrial production, and individual health monitoring from exhaled breath. To achieve this goal, bimetallic Au@Pt core-shell nanospheres (BNSs) functionalized-electrospun ZnFe2O4 nanofibers (ZFO NFs) are prepared in this work. Compared to pure NFs-650 analogue, the ZFO NFs/BNSs-2 sensor exhibits a stronger mean response (3.32 vs 1.84), quicker response/recovery speeds (33 s/28 s vs 54 s/42 s), and lower operating temperature (188 vs 273 °C) toward 0.5 ppm acetone. Note that an experimental detection limit of 30 ppb is achieved, which ranks among the best cases reported thus far. Besides the demonstrated excellent repeatability, humidity-enhanced response, and long-term stability, the selectivity toward acetone is remarkably improved after BNSs functionalization. Through material characterizations and DFT calculations, all these improvements could be attributed to the boosted oxygen vacancies and abundant Schottky junctions between ZFO NFs and BNSs, and the synergistic catalytic effect of BNSs. This work offers an alternative strategy to realize selective subppm acetone under high-humidity conditions catering for the future requirements of noninvasive breath diabetes diagnosis in the field of individual healthcare.

ErFeO3/α-Fe2O3 nanocomposites derived from MIL-100(Fe) for acetone sensing

Acetone, a flammable and volatile liquid, is toxic and can affect human well-being. Additionally, its presence in exhaled air can indicate the state of human respiratory health. Therefore, the investigation of an acetone gas sensor holds significant urgency in the realm of scientific research. Metal-organic frameworks (MOFs) exhibit significant promise in the field of gas detection due to their extensive surface areas, remarkable porosity, and the inclusion of unsaturated metallic sites. The study conducted the preparation of ErFeO3/α-Fe2O3 nanocomposites through impregnation and oxidation roasting methods. EF21 (MEr(NO3)3∙6H2O:MMIL-100(Fe) = 2:1) exhibited a large surface area of 43.7 m2/g and a high abundant oxygen vacancy of 12.5 %. Gas sensing experiments revealed that the EF21-based gas sensor exhibited a strong response of 55 towards 100 ppm acetone, with a low detection limit of 2 ppm (S = 3.3). Notably, the sensor demonstrated excellent selectivity towards acetone over other volatile organic compounds (e.g., ethanol, methanol, ammonia, ether, and toluene) in gas selectivity tests. Moreover, the EF21-based gas sensor maintained its responsiveness to acetone even under high relative humidity conditions (RH:90 %, S = 27) and demonstrated stability over a 15-day long-term test. The study provided a comprehensive explanation of the gas sensing mechanism responsible for the enhanced performance observed in ErFeO3/α-Fe2O3 through detailed analyses.