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Rational design of sensitivity enhanced and stability improved TEA gas sensor assembled with Pd nanoparticles-functionalized In2O3 composites
摘要： In this work, special triethylamine (TEA) gas sensors based on Pd nanoparticles (NPs)-decorated In2O3 microstructures with different Pd amount have been successfully fabricated. The optimal sensor based on 3 wt% Pd-loaded In2O3 shows higher gas response compared with other content of Pd wt% and exhibits the highest response of 47.56 when exposed to 50 ppm TEA gas. Furthermore, 3 wt% Pd NPs-In2O3 sensor not only possesses superior response and recovery properties of 4 s and 17 s under 50 ppm TEA gas, respectively, but also displays outstanding selectivity to TEA gas at the existence of other interfering gases. Based on the model of depletion layer, the possible gas sensing mechanism are studied and the results show that, the synergistic effect between the sensitization exerted by Pd nanoparticles and structural defects may be responsible for the remarkably enhanced TEA sensing performance. Considering the superiority including low cost, simple structure, and facile fabrication, 3 wt% Pd NPs-In2O3 microstructures are promising for high-performance TEA sensing applications.
关键词： Triethylamine,In2O3,Gas sensors
更新于2025-11-14 17:04:02
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Metal–organic framework-derived ZnO hollow nanocages functionalized with nanoscale Ag catalysts for enhanced ethanol sensing properties
摘要： Increase of porosity and functionalization with nanoscale catalysts are two significant aspects for achieving high-performance metal oxide-based resistive gas sensors. In this work, a simple metal–organic framework (MOF) route has been developed to fabricate Ag nanocatalysts functionalized ZnO hollow nanocages (NCs). Nanoscale Ag catalysts with a small size of approximately 10 nm are uniformly encapsulated within the cavities of MOFs (ZIF-8). The high porosity, hollow structure, and functionalization with uniformly-distributed nanoscale Ag catalysts have been simultaneously achieved for MOF-derived ZnO. This type of porous Ag–ZnO hollow NCs show much enhanced ethanol sensing performances and reduced operating temperature in comparison with pure ZnO nanoparticles (NPs) and ZnO NCs. In particular, the 1 ml Ag–ZnO NCs exhibit the highest response of 84.6 to 100 ppm ethanol at 250 °C, which is 6.4 and 3.3 times higher than those of pure ZnO NPs and ZnO NCs at the optimum operating temperature of 275 °C, respectively. The Ag–ZnO NCs also display fast response/recovery times, good ethanol selectivity, and response reproducibility. The enhanced ethanol sensing properties are attributed to the synergistic effects of several points including the electron sensitization effects and catalytic effects of nanoscale Ag catalysts, porous and hollow structures, high surface area, and high surface O? species absorbing capability of Ag–ZnO NCs.
关键词： ZnO,Gas sensors,Metal–organic frameworks,Ag,Hollow
更新于2025-11-14 17:03:37
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Combination of Pd loading and electron beam irradiation for superior hydrogen sensing of electrospun ZnO nanofibers
摘要： We evaluated the hydrogen gas-sensing characteristics of Pd-loaded (0.1, 0.3, 0.6, and 1 wt%) ZnO nano?bers prepared by a facile electrospinning technique and the e?ect of di?erent electron beam (e-beam) doses (50, 100, and 150 kGy) on sensing performance. The sensor loaded with 0.6 wt% Pd had the highest response to hydrogen among the Pd-loaded sensors. The sensor irradiated with 150 kGy had the high response (Ra/Rg) of 74.7–100 ppb of H2 at 350 °C. Metallization e?ects in ZnO, the formation of structural defects due to e-beam irradiation, the catalytic activity of Pd, and the presence of ZnO–Pd heterojunctions were the main factors yielding high sensitivity towards H2. The strategy of combining e-beam irradiation and Pd loading to enhance H2 sensing can be applied to realize reliable gas sensors and the widespread use of hydrogen as a green energy alternative to fossil fuels.
关键词： H2,Electron beam irradiation,Gas sensors,ZnO nano?bers,Pd nanoparticles
更新于2025-09-23 15:23:52
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Understanding the Sensing Mechanism of Rh2O3 loaded In2O3
摘要： The effect of Rh loading on CO sensing was studied for the case of In2O3. This was done by performing measurements with sensors based on loaded and unloaded materials that were performed at an operation temperature of 300 °C in the presence of low background oxygen concentration according to an experimental procedure that was demonstrated to help clarify the reception/transduction functions of loaded Semiconducting Metal Oxides (SMOX). The experimental investigation methods were DC resistance and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that in the case of Rh2O3 loaded In2O3 the reaction primary takes place on the Rh2O3 cluster and the electrical properties of the In2O3 are controlled by the pinning of the SMOX Fermi-level to the one of the Rh2O3 cluster.
关键词： SMOX,surface chemistry,gas sensors,operando,Rh2O3 loading,DRIFTS,In2O3
更新于2025-09-23 15:23:52
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SO <sub/>2</sub> -sensing properties of NiO nanowalls synthesized by the reaction of Ni foil in NH <sub/>4</sub> OH solution
摘要： Nickel oxide (NiO) is a p-type metal-oxide semiconductor with wide-ranging applications. Recent studies have focused on the gas-sensing properties of this semiconductor. This study introduces an easy process for growing NiO nanowalls on a glass substrate using Ni foil and aqueous NH4OH. The morphology and structure of the NiO nanowalls are investigated and confirmed by field-emission scanning electron microscopy and x-ray diffraction (XRD) analyses. The gas-sensing properties of the prepared nanowalls are tested using a dynamic gas-testing system wherein the target gases are H2S, NO2, NH3 and SO2. Gas-sensing data show that the synthesized NiO nanowalls are highly responsive toward SO2. Additionally, a sensing device prepared based on the NiO nanowalls is found to be stable during measurements, exhibiting a linear variation with changes in SO2 concentration.
关键词： gas sensors,surface reactions,nanowalls,NiO
更新于2025-09-23 15:23:52
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Highly Stable and Ultrafast Hydrogen Gas Sensor Based on 15 nm Nanogaps Switching in a Palladium-Gold Nanoribbons Array
摘要： Palladium (Pd) nanogap hydrogen gas (H2) sensors based on the large volume expansion of β phase palladium hydride (β-PdH) are highly promising, owing to their fast and accurate sensing capability at room temperature in air. However, such sensors do not work well at H2 concentrations below 1%. At such low H2 concentrations, Pd exists as α-PdH, which has a slow and insufficient volume expansion and cannot completely close nanogaps. Furthermore, the lattice strains induced from the phase transition (α-PdH → β-PdH) behavior degrade the stable and repeatable long-term sensing capability. Here, these issues are resolved by fabricating an array of periodically aligned alloyed palladium–gold nanoribbons (PdAu NRB) with uniform 15 nm nanogaps. The PdAu NRB sensor enables highly stable and ultrafast H2 sensing at the full detection range of H2 concentrations from 0.005% to 10% along with the excellent limit of detection (≈0.0027%), which is sufficiently maintained even after seven months of storage in ambient atmosphere. These breakthrough results will pave the way for developing a practical high-performance H2 sensor chip in the future hydrogen era.
关键词： palladium nanogap,nanoribbon,hydrogen gas sensors,polystyrene thermal shrinkage
更新于2025-09-23 15:22:29
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Morphology Controllable Synthesis of Hierarchical WO3 Nanostructures and C2H2 Sensing Properties
摘要： In this paper, we reported the morphology controllable synthesis of hierarchical WO3 nanostructures, i.e. nanorods, nanospheres and nanoflowers, via a facile hydrothermal route. All the obtained WO3 nanostructures were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET), respectively. A possible growth mechanism for the three various nanomaterials was proposed in detail. WO3 based gas sensors were fabricated with the synthesized nanomaterials and the gas sensing performances to acetylene (C2H2), one of the fault characteristic gases dissolved in power transformer oil, were systematically measured. It was found that the sensor based on nanosheet-assembled nanoflowers with largest surface (56.74 m2g-1) exhibits the highest sensing performance including gas response (32.31) and response-recovery time (12 s, 17 s) to 200 ppm C2H2. The results indicate that WO3 sensing materials could be a promising choice for synthesizing high-performance C2H2 sensors for the judgement of the early latent faults of the oil immersed transformer.
关键词： Hierarchical WO3,Gas sensors,Growth mechanism,C2H2 sensing performances
更新于2025-09-23 15:22:29
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Properties of Porous Silicon Precipitated with Nickel for Gas Sensors
摘要： The preparation and properties of modified porous silicon is discussed and a proposal of a sensitive layer for a gas detector is presented. The modification is done by precipitation and electrochemical deposition of nickel. The morphology of sample surfaces is examined by atomic force microscopy and scanning electron microscopy (SEM). SEM-coupled energy dispersive spectroscopy is used to analyse the chemical composition of the samples. Magnetic response is measured with a SQUID magnetometer. Electrochemical impedance spectroscopy is used to study the sensitivity of the samples to isopropanol vapour in the presence of alternating electric current. A series of samples prepared with a higher anodic current density show higher sensitivity to isopropanol vapours in comparison to a lower anodic current.
关键词： Electrochemical Impedance Spectroscopy,Porous Silicon,Gas Sensors,SQUID,Electroless Nickel Deposition,Atomic Force Microscopy
更新于2025-09-23 15:22:29
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Superior Sensing Properties of Black Phosphorus as Gas Sensors: A Case Study on the Volatile Organic Compounds
摘要： The unique structure and prominent properties of black phosphorus (BP) and its monolayer and multilayers in device applications have attracted significant attention to this elemental 2D material. In this study, a comprehensive evaluation of the candidacy of monolayer BP as a channel material for high-performance volatile organic compound (VOC) sensors is conducted combining first-principles density functional theory calculations and non-equilibrium Green’s function formalism. The adsorption configurations and energetics of several typical VOCs (ethanol, propionaldehyde, acetone, toluene, and hexane) on monolayer BP are examined and it is demonstrated that VOCs generally exhibit stronger interaction with monolayer BP than with the widely studied monolayer MoS2, indicative of monolayer BP potentially being a more sensitive VOC sensor. Monolayer BP is shown to exhibit highly anisotropic transport behaviors, whereas the absolute modification of current–voltage responses due to VOCs is found to show a trend that is direction independent. Moreover, the adsorption of VOCs on monolayer BP is strong enough to resist thermal disturbance, yet allows fast recovery time. The results suggest that BP is a compelling and feasible candidate for sensing applications of VOCs.
关键词： density functional theory calculations,gas sensors,black phosphorus,volatile organic compounds,non-equilibrium Green’s function formalism
更新于2025-09-23 15:22:29
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Direct-printed nanoscale metal-oxide-wire electronics
摘要： One-dimensional metal oxide (MO) micro-wires and nano-wires (MOWs) can be excellent functional units for integrated and transparent electronics. However, MOWs produced using conventional synthesis methods are short, uncontrollable, and randomly-distributed, so they cannot be easily used to fabricate high-density transistor arrays with precisely-controlled MOW-channels. Here, we describe a large-scale direct-printed universal nanoscale MOW electronics which includes highly-aligned, digitally-controlled and arbitrarily-long MOW arrays and various nanoscale applications of MOW field-effect transistors (FETs), neuromorphic synaptic transistors, and gas sensors. Broad classes of pristine, doped and alloyed MOWs are fabricated, so we demonstrated all-MOWFETs composed of conducting indium oxide (In2O3) wires and semiconducting indium zinc oxide (IZO) wires; the devices show a high carrier mobility μ ~17.67 cm2 V-1 s-1, comparable to μ of MO thin-film FETs. MOW synaptic transistors show presynaptic signals dependent postsynaptic behaviors similar to biological synaptic responses; which can be promising nano-electronic units of high-density neuromorphic devices. We also demonstrated MOW gas sensors which show high response to NO2 gas. Our direct-printed, large-scale, and individually-controlled MOW electronics would be a promising approach in development of industrially-viable MOW electronics and open new horizons for precisely-controlled inorganic MOW electronics and nanoscale printed electronics.
关键词： synaptic transistors,metal oxide nanowires,metal oxide gas sensors,nanowire printing,metal oxide transistors,nanowire electronics
更新于2025-09-23 15:22:29