Latest ArticlesFlexible trimethylamine sensor has been realized based on In2O3 nanofibers via electrospinning and a deposition technique. The web-like In2O3 nanofibers with high length-to-diameter ratios are benefit for gas adsorption and desorption. High trimethylamine sensing properties are observed. The sensors can detect trimethylamine gas down to 1 ppm at 80 ℃ with the response up to 3.8. Additionally, rapid response (6 s) and recovery (10 s) behavior can also be obtained. Good reliability and flexibility are observed in 100 bending/extending cycles. Our results open a new route to construct flexible gas sensors in practice.
In order to improve the convenience and sensitivity of amphetamines drug testing and reduce the threat of drugs to humans, we have designed a QCM gas sensor to detect amine-containing drugs. The sensing material is designed based on the chemical nature of amine drugs. The sensing mechanism is derived from a reversible Schiff base interaction between the amino group of the drug and the carbonyl group of the novel calix[6]arene derivatives as well as the hydrogen bond interaction between amino group and hydroxyl. The new composite material was well characterized by different analytical techniques including 1H nuclear magnetic resonance (1H-NMR), fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM), transmission electron microscope (TEM), Raman spectra, powder X-ray diffraction, etc. The sensing experiments were conducted by coating the composite onto quartz crystal microbalance (QCM) transducers. The experimental results indicated that the novel calixarene derivatives and their GO complexes based on the design have excellent selectivity, high sensitivity and repeatability to β-phenylethylamine.
The morphological and structural design provides an efficient protocol to optimize the performance of gas sensing materials. In this work, a gas sensor with high sensitivity for triethylamine (TEA) detection is developed based on p-type NiCo2O4 hierarchical microspheres. The NiCo2O4 microspheres, synthesized by a hydrothermal route, have a three-dimensional (3D) urchin-like structure assembled by nanorod building blocks. The structure-property correlation has been investigated by powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscope, scanning electron microscope, N2 adsorption-desorption tests and comprehensive gas sensing experiments. The influence of calcination temperature on the morphological structure and sensing performances has been investigated. Results reveal that the material annealed at 300 ℃ has a very large specific surface area of 125.27 m2/g, thereby demonstrating the best TEA sensing properties including high response and low limit of detection (145 ppb), good selectivity and stability. The further increase of the calcination temperature leads to the collapse of the 3D hierarchical structure with significantly decreased surface area, which is found to decline the sensing performances. This work indicates the promise of ternary p-type metal oxide nanostructures for application in highly sensitive gas sensors.
Dihydronicotinamide adenine dinucleotide (NADH) is an important enzyme in all living cells, which is found to be abnormally expressed in cancer cells. Since it is redox-active, an electrochemical detection method would be suitable for monitoring its concentration in biological fluids. Here we present a strategy for specific determination of NADH in real human serum by using RhIr@MoS2 nanohybrids based microsensor. To implement the protocol, RhIr nanocrysrals are in-situ grown onto MoS2 interlayers forming a nanohybrid structure (RhIr@MoS2). After being locally deposited on an electrochemical microsensor, it could be used for the analysis of NADH. The developed RhIr@MoS2 nanohybrids based microsensor possesses the ability for analyzing NADH at the applied potential of 0.07 V (much lower than most reported values). The detection limit is evaluated as low as 1 nmol/L even in bovine serum albumin (BSA) media. In addition, the sampling analysis of human serum from cancer patients and health controls shows that the microsensor displays good diagnostic sensitivity and specificity, illustrating that this developed detection technique is a relatively accurate method for measuring NADH in biological fluids. The proposed electrochemical microsensor assay also owns the benefits of convenience, disposable and easy processing, which make it a great possibility for future point-of-care cancer diagnosis.
Detection of trace-level hydrogen sulfide (H2S) gas is of great importance whether in industrial production or disease diagnosis. This research presents a novel H2S gas sensor based on integrated resonant dual-microcantilevers which can identify and detect trace-level H2S in real-time. The sensor consists of two integrated resonant microcantilever sensors with different functions. One cantilever sensor can identify H2S by outputting positive frequency shift signals, while the other cantilever sensor will detect H2S as a normally used cantilever sensor with negative frequency shifts. Combined the two cantilever sensors, the proposed gas sensor can distinguish H2S from a variety of common gases, and the detection limit to H2S of the sensor is as sensitive as below 1 ppb.
Tin dioxide is important gas sensor material and has wide applications in the detection of toxic gases and volatile organic compounds. Here, we synthesized a 3D laminated structural CuO/SnO2 material possessing p-n heterostructures. The morphology and structure were characterized by XRD, SEM, TEM and XPS techniques and the sensing properties were investigated for the detection of triethylamine (TEA). The results indicate that 3D laminated CuO/SnO2 material, assembled by lamellae consisting of ordered nanoparticles, exhibit an enhanced sensing performance compared with SnO2, and notably, CuO/SnO2 with size less than 1 μm has obvious high selectivity in the detection of 100 ppm TEA. Particularly, it has a high response and stability to 1 and 5 ppm TEA (S is 8 and 33), and that is higher than SnO2 material, suggesting 3D laminated CuO/SnO2 is an effective candidate material served as sensor platform to detect low-concentration amines.
Ethylene (C2H4), as a plant hormone, its emission can be served as an indicator to measure fruit quality. Due to the limited physiochemical reactivity of C2H4, it is a challenge to develop high performance C2H4 sensors for fruit detection. Herein, this paper presents a resistive-type C2H4 sensor based on Pd-loaded tin oxide (SnO2). The C2H4 sensing performance of proposed sensor are tested at optimum operating temperature (250 ℃) with ambient relative humidity (51.9% RH). The results show that the response of Pd-loaded SnO2 sensor (11.1, Ra/Rg) is about 3 times higher than that of pristine SnO2 (3.5) for 100 ppm C2H4. The response time is also significantly shortened from 7 s to 1 s compared with pristine SnO2. Especially, the Pd-loaded SnO2 sensor possesses good sensitivity (0.58 ppm-1) at low concentration (0.05-1 ppm) with excellent linearity (R2=0.9963) and low detection limit (50 ppb). The high sensing performance of Pd-loaded SnO2 are attributed to the excellent adsorption and catalysis effects of Pd nanoparticle. Meaningfully, the potential applications of C2H4 sensor are performed for monitoring the maturity and freshness of fruits, which presents a promising prospect in fruit quality evaluation.
Due to the "trade-off" effect between the high water adsorption and low stability under high Relative Humidity of polymer matrix, fabrication of resistive-type polymer-based humidity sensors with a wide impedance response and excellent stability in high relative humidity remains a great challenge. Aim at solving that, a novel polymeric humidity sensing matrix, specifically a tadpole-shaped, polyhedral oligomeric silsesquioxane (POSS) containing block copolymers (BCPs) of POSS-poly(methyl methacrylate)-polystyrene (POSS-PMMA-SPS) were proposed. This novel BCP was synthesized using atom transfer radical polymerization (ATRP) employing a two-step approach, and following post sulfonation, a series of sulfonated BCPs (POSS-PMMA-SPS) with different sulfonation degree was obtained. The subject humidity sensors were produced using different sulfonated BCPs employing a dip-coating technique, and three wide-impedance response humidity sensors were produced. Each of these sensors exhibited an excellent humidity-sensing response of more than 104 within the humidity range from 11% to 95% RH. In particular, the humidity sensor S-6 that had a proper degree of sulfonation presented a relatively fast response (t90% of 11 s and 80 s in both the water adsorption and desorption processes), and superior repeatability for more than 30 days.
Metal oxide semiconductors (MOS)-reduced graphene oxide (rGO) nanocomposites have attracted great attention for room-temperature gas sensing applications. The development of novel sensing materials is the key issue for the effective detection of ammoniagas at room temperature. In the present work, the novel reduced graphene oxide (rGO)-In2O3 nanocubes hybrid materials have been prepared via a simple electrostatic self-assembly strategy. Characterization results exhibit that the intimate interfacial contact between In2O3 nanocubes and the rGO sheets are achieved. Particularly, the as-prepared rGO/In2O3 nanocomposites displayed high sensitivity, fast response and excellent selectivity towards ammonia (NH3) at room-temperature, which clearly uncovers the merit of structural design and rational integration with rGO sheets. The superior gas sensing performance of the rGO/In2O3 nanocomposites can be attributed to the synergetic effects of rGO sheets and porous In2O3 nanocubes. The reported synthesis offers a general approach to rGO/MOS-based semiconductor composites for room-temperature gas sensing applications.
In this paper, the Pt/SnO2 nanostructures were prepared via a facile one-step microwave assisted hydrothermal route. The structure of the introduced Pt/SnO2 and its gas-sensing properties toward CO were investigated. The results from the TEM test reveal that Pt grows on the SnO2 nanostructure, which was not found for bulk in this situ method, constructing Pt/SnO2. The results indicated that the sensor using 3.0 wt% Pt/SnO2 to 100 ppm carbon monoxide performed a superior sensing properties compared to 1.5 wt% and 4.5 wt% Pt/SnO2 at 225 ℃. The response time of 3.0 wt% sensor is 16 s to 100 ppm CO at 225 ℃. Such enhanced gas sensing performances could be attributed to the chemical and electrical factors. In view of chemical factors, the presence of Pt facilitates the surface reaction, which will improve the gas sensing properties. With respect to the electrical factors, the Pt/SnO2 plays roles in increasing the sensor's response due to its characteristic configuration. In addition, the one-step in situ microwave assisted process provides a promising and versatile choice for the preparation of gas sensing materials.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
