The rise in gas leakage incidents underscores the urgent need for advanced gas-sensing platforms with ultra-low concentration detection capability.Sensing gate field effect transistor(FET)gas sensors,renowned for the ...The rise in gas leakage incidents underscores the urgent need for advanced gas-sensing platforms with ultra-low concentration detection capability.Sensing gate field effect transistor(FET)gas sensors,renowned for the gas-induced signal amplification without directly exposing the channel to the ambient environment,play a pivotal role in detecting trace-level hazardous gases with high sensitivity and good stability.In this work,carbon nanotubes are employed as the conducting channel,and yttrium oxide(Y_(2)O_(3))is utilized as the gate dielectric layer.Noble metal Pd is incorporated as a sensing gate for hydrogen(H_(2))detection,leveraging its catalytic properties and unique adsorption capability.The fabricated carbon-based FET gas sensor demonstrates a remarkable detection limit of 20×10^(–9) for H_(2) under an air environment,enabling early warning in case of gas leakage.Moreover,the as-prepared sensor exhibited good selectivity,repeatability,and anti-humidity properties.Further experiments elucidate the interaction between H_(2) and sensing electrode under an air/nitrogen environment,providing insights into the underlying oxygen-assisted recoverable sensing mechanism.It is our aspiration for this research to establish a robust experimental foundation for achieving high performance and highly integrated fabrication of trace gas sensors.展开更多
Hydrogen is known for its efficient combustion,abundant natural availability,and environmentally friendly characteristics.It is recognized as a promising energy source for the future and is already utilized in various...Hydrogen is known for its efficient combustion,abundant natural availability,and environmentally friendly characteristics.It is recognized as a promising energy source for the future and is already utilized in various industries,including petrochemicals,electronics,food processing,aerospace,and new energy vehicles.However,challenges arise in the storage and use of hydrogen owing to its tendency to leak,its potential for explosion within a specific concentration range of 4%-75%,and itslow ignition energy requirements.Consequently,there is a demand for hydrogen sensors capable of quickly and accurately detecting low levels of hydrogen leaks.Microelectromechanical systems-based chemiresistive hydrogen sensors offer advantages such as low cost,compact size,low energy consumption,and superior sensing performance,making them a major focus of recent research.This article provides a comprehensive overview and comparison of the sensing principles of various hydrogen sensors,including chemiresistive sensors,electrochemical sensors,thermocatalytic sensors,acoustic sensors,and mechanical sensors.Micro-chemiresistive hydrogen sensors exhibit high sensitivity,low cost,and ease of integration,making them highly promising for practical applications.In response to the challenges encountered in practical applications of chemiresistive hydrogen sensors,such as high operating temperatures and high power consumption,this review explores emerging trends in chemiresistive hydrogen sensor technology from the perspectives of novel materials and activation methods.Finally,it discusses the applications and potential further developments of chemiresistive hydrogen sensors.展开更多
The steel contains a small amount of hydrogen which will escape during the heat treatment.The hydrogen pressure in 16MnRE steel was investigated with a hydrogen sensor,which used SrCe0.95Yb0.05O3-α proton conductor a...The steel contains a small amount of hydrogen which will escape during the heat treatment.The hydrogen pressure in 16MnRE steel was investigated with a hydrogen sensor,which used SrCe0.95Yb0.05O3-α proton conductor as a solid electrolyte,YHx＋YH2z as a solid state reference electrode and Ni wire as electrode constructing a hydrogen concentration cell,shown as Ni｜YHx＋YH2z ｜SrCe0.95Yb0.05O3-α ｜[H] steel ｜Ni.The response time of sensor is less than 10s.The relational expression of hydrogen partial pressure with temperatures was determined using two shape proton conductors.The results showed the regularity in experimental temperature range,and the hydrogen partial pressure increased as its temperature was raised.展开更多
The principle, design, construction and performance of the amperometric and potentiometric sensors for measuring the permeation rate of hydrogen through the wall of metal equipment were investigated in order to develo...The principle, design, construction and performance of the amperometric and potentiometric sensors for measuring the permeation rate of hydrogen through the wall of metal equipment were investigated in order to develop a new type of hydrogen sensor with high accuracy. The transient curves of hydrogen permeation under a given charging condition were employed to evaluate the performance of two types of hydrogen sensors. The relative deviation of the hydrogen concentration detected with two types of sensors under the same condition varied from 3.0% to 13%. The accuracy, response time, reproducibility, and installation were discussed and compared. Response time of the potentiometric sensor （E-sensor） was shorter than that of the amperometric sensor （I-sensor）. Both types of sensors exhibited good reproducibility. Development of I-sensor composed of a kind of proton conductor adhesives or non-fluid electrolytes which contain two functions of high electrical conductivity and a strong adhesion will be a promising prospect in order to measure hydrogen permeation at high temperature.展开更多
Hydrogen is a promising renewable energy source for fossil-free transportation and electrical energy generation.However,leaking hydrogen in high-temperature production processes can cause an explosion,which endangers ...Hydrogen is a promising renewable energy source for fossil-free transportation and electrical energy generation.However,leaking hydrogen in high-temperature production processes can cause an explosion,which endangers production workers and surrounding areas.To detect leaks early,we used a sensor material based on a wide bandgap aluminum nitride(AlN)that can withstand a high-temperature environment.Three unique AlN morphologies(rod-like,nest-like,and hexagonal plate-like)were synthesized by a direct nitridation method at 1400℃usingγ-AlOOH as a precursor.The gas-sensing performance shows that a hexagonal plate-like morphology exhibited p-type sensing behavior and showed good repeatability as well as the highest response(S=58.7)toward a 750 ppm leak of H2 gas at high temperature(500°C)compared with the rod-like and nest-like morphologies.Furthermore,the hexagonal plate-like morphology showed fast response and recovery times of 40 and 82 s,respectively.The surface facet of the hexagonal morphology of AlN might be energetically favorable for gas adsorption–desorption for enhanced hydrogen detection.展开更多
In this paper,palladium-silver (Pd-Ag) system was studied for hydrogen sensing.Nanofilm of Pd-Ag was fabricated on a porous ceramic substrate through a combination of microfabrication techniques.The electric resistan...In this paper,palladium-silver (Pd-Ag) system was studied for hydrogen sensing.Nanofilm of Pd-Ag was fabricated on a porous ceramic substrate through a combination of microfabrication techniques.The electric resistance of the zigzag-shaped microstructure was measured toward hydrogen concentration change.The sensing element demonstrates high sensitivity,fast response and fast recovery to hydrogen.The Pd-Ag film was characterized by scanning electron microscopy (SEM) equipped with X probe to correlate its physical and chemical properties to its sensing performance.The present sensor is very promising for room temperature hydrogen leakage detection and related applications.The temperature effect on the sensing performance of the metal film was also investigated.展开更多
Peculiarities of the low-frequency noise spectroscopy of hydrogen gas sensors made on MgFeO4 n-type porous semiconductor covered by the palladium catalytic nanosize particles are investigated. Behavior of the low-freq...Peculiarities of the low-frequency noise spectroscopy of hydrogen gas sensors made on MgFeO4 n-type porous semiconductor covered by the palladium catalytic nanosize particles are investigated. Behavior of the low-frequency noise spectral density and its exponent value from sensitive layer thickness in the frequency range 2 - 300 Hz are analyzed. Sensitivity of the sensor calculated by the noise method is several tenth times higher as compared with the resistive method. It is shown that besides of the well-known applications, noise spectroscopy can be also used for definition of the unknown thickness of gas sensitive layer, for definition of the sensitive layer subsurface role in the formation of the low-frequency noises and for definition of the intensity of trapping-detrapping processes of the gas molecules.展开更多
Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate...Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate. Therefore, the development of hydrogen sensor with high accuracy and reliability that can detect hydrogen easily is required. Especially, a flexible hydrogen sensor is useful because it has a high degree of freedom with respect to the shape of location in which the sensor is to be located. A flexible hydrogen sensor—namely, a WO3 thin film formed on a PET film by the sol-gel method using photo irradiation—based on gasochromism of WO3 was developed. By irradiating a thin film, which was prepared by using WO3 precursor solution synthesized by the sol-gel method, with ultraviolet rays, a high-purity WO3 film could be prepared on PET at low temperature. The sensor was structured as a polystyrene (PS) film containing palladium (Pd) laminated on a WO3 film. The WO3 layer was porous, so the PS containing Pd atoms solution penetrated the WO3 layer. WO3 reacted with hydrogen gas and instantly turned blue as the transmittance of the WO3 layer changed. The sensor showed high reactivity even for hydrogen concentration below 4% (1%, 0.5%, 0.25%, and 0.1%), which was the lower limit of hydrogen ignition, and a linear relationship between hydrogen concentration and change in transmittance was found. Moreover, the resistance of the WO3 film significantly and instantaneously changed due to hydrogen-gas exposure, and the hydrogen concentration and resistance change showed a linear relationship. It is therefore possible to quantitatively detect low concentrations of hydrogen by using changes in transmittance and resistance as indices. Since these changes occur selectively under hydrogen at room temperature and normal pressure, they form the basis of a highly sensitive hydrogen sensor. Since the developed sensor is flexible, it has a high degree of freedom with respect to the shape of location in which the sensor is to be展开更多
Graphene has exceptional electrical,optical and thermal properties,and is widely used to create thinner,lighter and faster sensors.In this study,graphene was fabricated by mechanically exfoliating on the SiO_(2)/Si su...Graphene has exceptional electrical,optical and thermal properties,and is widely used to create thinner,lighter and faster sensors.In this study,graphene was fabricated by mechanically exfoliating on the SiO_(2)/Si substrate and the graphene field effect transistor(FET)was prepared by photolithography.Platinum(Pt)particles were doped on the surface of graphene by the hydrazine hydrate reduction method to endow a Pt/graphene sensor with gas-sensing properties.By being tested on a gas detection platform,the characteristics of the electrical(Ⅰ-Ⅴ)curves and resistance response curves were obtained in different hydrogen environments.The results show that the Pt/graphene sensor exhibits a high sensitivity to hydrogen at room temperature,with a resistance response rate of 33.35%at a hydrogen volume fraction of 1.00%.However,the sensitivity lifetime study shows an essential hysteresis in desorption process,which leads to gradually decreases in the resistance response rate.This research provides an improved production method of graphene-based gas sensors,which has a wide range of potential applications in aero-space industry.展开更多
A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the l...A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in theπ-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology.Since the hydrogen sensitivity between the notch and flank wavelengths of theπ-phase-shifted grating is different due to the partial coating only on theπ-phase-shifted grating region,the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper.The hydrogen calibration results show that the sensor shows the good response and repeatability.At the temperature of 20 and℃the hydrogen concentration of 2%,the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm,respectively.展开更多
Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face chal...Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.展开更多
A fiber-optic Fabry-Perot hydrogen sensor was developed by measuring the fringe contrast changes at different hydrogen concentrations. The experimental results indicated that the sensing performance with the Pd-Y film...A fiber-optic Fabry-Perot hydrogen sensor was developed by measuring the fringe contrast changes at different hydrogen concentrations. The experimental results indicated that the sensing performance with the Pd-Y film was better than that with the Pd film. A fringe contrast with a decrease of 0.5 dB was detected with a hydrogen concentration change from 0% to 5.5%. The temperature response of the sensor was also measured.展开更多
In this paper, high-quality nanocrystalline SnO_2 thin film was grown on bare Si(100) substrates by a sol–gel method. A metal–semiconductor–metal gas sensor was fabricated using nanocrystalline SnO_2 thin film and ...In this paper, high-quality nanocrystalline SnO_2 thin film was grown on bare Si(100) substrates by a sol–gel method. A metal–semiconductor–metal gas sensor was fabricated using nanocrystalline SnO_2 thin film and palladium(Pd)metal. The contact between Pd and nanocrystalline SnO_2 film is tunable. Ohmic barrier contact was formed without addition of glycerin, while Schottky contact formed by adding glycerin. Two kinds of sensor devices with Schottky contact were fabricated(Device 1: 8 h, 500 °C; Device 2: 10 h, 400 °C). The room temperature sensitivity for hydrogen(H_2) was120 and 95 % in 1000 ppm H_2, and the low power consumption was 65 and 86 l W for two devices, respectively. At higher temperature of 125 °C, the sensitivity was increased to 195 and 160 %, respectively. The sensing measurements were repeatable at various temperatures(room temperature, 75, 125 °C) for over 50 min. It was found that Device 1 has better sensitivity than Device 2 due to its better crystallinity. These findings indicate that the sensors fabricated on bare Si by adding glycerin to the sol solution have strong ability to detect H_2 gas under different concentrations and temperatures.展开更多
The principle, construction and application of two types of electrochemical sensors-amperometric and potentiometric are surveyed. Both types of sensors are very sensitive to changes in temperature. The accuracy of hyd...The principle, construction and application of two types of electrochemical sensors-amperometric and potentiometric are surveyed. Both types of sensors are very sensitive to changes in temperature. The accuracy of hydrogen measurement depends on both the precision of sensors developed and the reliable technique of installation and security of sensors. The two types of sensors have been used for in-situ determining hydrogen permeated in steels owing to a corrosive reaction, a hydrogen gas circumstance at elevated temperatures and high pressure or also a pretreatment process such as pickling and plating process, etc.展开更多
A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobal...A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.展开更多
Hydrogen gas sensor device with simple planar structure based on p^+ silicon substrate with n-type epi-layer was fabricated only by using a lift-off technique of an evaporated metal film.The device consists of Ohmic s...Hydrogen gas sensor device with simple planar structure based on p^+ silicon substrate with n-type epi-layer was fabricated only by using a lift-off technique of an evaporated metal film.The device consists of Ohmic source and drain electrodes and platinum Schottky gate electrode.This sensor device has a little similar property as FET.Current-voltage characteristics between the source and drain of the device are sensitive to hydrogen gas.The voltage difference between in hydrogen ambient and oxygen ambient is about 2.3 volts for a constant current of 0.9 mA.The device can detect 0.4% hydrogen gas in air.Based on oxidation reaction of hydrogen on the surface of the platinum gate,hydrogen sensitivity of the device changes by the coexisting oxygen concentration.Electrons flow in the buried channel formed between the gate electrode and the p^+n junction.It was confirmed that the gate bias influences the properties.The current-voltage property changes also depending on the wiring method.展开更多
The Prussian blue nanoparticles（PBNPs） were prepared by a self-assembly process, on a glassy carbon（GC） electrode modified with a poly（o-phenylenediamine）（Po PD） film. The stepwise fabrication process of PBNPs...The Prussian blue nanoparticles（PBNPs） were prepared by a self-assembly process, on a glassy carbon（GC） electrode modified with a poly（o-phenylenediamine）（Po PD） film. The stepwise fabrication process of PBNPs-modified Po PD/GCE was characterized by scanning electron microscopy（SEM） and electrochemical impedance spectroscopy. The prepared PBNPs showed an average size of 70 nm and a homogeneous distribution on the surface of modified electrodes. The PBNPs/Po PD/GCE showed adequate mechanical, electrochemical stability and good sensitivity in comparison with other PB based H2O2 sensors. The present modified electrode exhibited a linear response for H2O2 reduction over the concentration range of 1–58.22 mmol L ^-1with a detection limit of ca. 0.8 mmol L ^-1（S/N = 3）, and sensitivity of 3187.89 m A（mol L ^-1） ^-1cm ^-2using the amperometric method. This sensor was employed for the H2O2 determination in real sample and also exhibited good interference resistance and selectivity.展开更多
An optical hydrogen sulfide(H_2S) sensor based on wavelength modulation spectroscopy with the second harmonic(2f) corrected by the first harmonic(1f) signal(WMS-2f/1f) is developed using a distributed feedback(DFB) la...An optical hydrogen sulfide(H_2S) sensor based on wavelength modulation spectroscopy with the second harmonic(2f) corrected by the first harmonic(1f) signal(WMS-2f/1f) is developed using a distributed feedback(DFB) laser emitting at 1.578 μm and a homemade gas cell with 1-m-long optical path length. The novel sensor is constructed by an electrical cabinet and an optical reflecting and receiving end. The DFB laser is employed for targeting a strong H_2S line at 6 336.62 cm^(-1) in the fundamental absorption band of H_2S. The sensor performance, including the minimum detection limit and the stability, can be improved by reducing the laser intensity drift and common mode noise by means of the WMS-2f/1f technique. The experimental results indicate that the linearity and response time of the sensor are 0.999 26 and 6 s(in concentration range of 15.2—45.6 mg/m^3), respectively. The maximum relative deviation for continuous detection(60 min) of 30.4 mg/m^3 H_2S is 0.48% and the minimum detection limit obtained by Allan variance is 79 μg/m^3 with optimal integration time of 32 s. The optical H_2S sensor can be applied to environmental monitoring and industrial production, and it has significance for real-time online detection in many fields.展开更多
hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxi...hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxidase(HRP)was then immobiliged on the DMFc-Nafion film,forming a HRp-DMFc-Nafion modi- fied electrode. The chracteristics of the sensor has been shown by cyclic voltam- metry and constant potential measurements,The sensor responds fastly to hydro- gen peroxide,the time required to reach 95%of the steady-state current is less than 50s. The sensor displays a sensitive catalytic current response to hydrogen peroxide and can be operated at a potential range in which the oxidation of common interfering species,such as ascorbic acid and uric acid,does not occur. The sensor is stable for 20 days and its detection limit is 1 μmol/L.展开更多
Silk is widely used in the production of high-quality textiles.At the same time,the amount of silk textiles no longer in use and discarded is increasing,resulting in significant waste and pollution.This issue is of gr...Silk is widely used in the production of high-quality textiles.At the same time,the amount of silk textiles no longer in use and discarded is increasing,resulting in significant waste and pollution.This issue is of great concern in many countries where silk is used.Hydrogen peroxide as a naturally occurring compound is an important indicator of detection in both biology and the environment.This study aims to develop a composite fiber with hydrogen peroxide-sensing properties using discarded silk materials.To achieve this goal,firstly,polydopamine(PDA)was used to encapsulate the ZnFe_(2)O_(4) NPs to achieve the improvement of dispersion,and then regenerated silk fibroin(RSF)and PDA@ZnFe_(2)O_(4)/RSF hybrid fibers are prepared by wet spinning.Research has shown that PDA@ZnFe_(2)O_(4)/RSF demonstrates exceptional sensitivity,selectivity,and stability in detecting hydrogen peroxide,while maintaining high mechanical strength.Furthermore,the complete hybridization of PDA@ZnFe_(2)O_(4) with silk fibroin not only results in the combination of the durability of silk fibroin and PDA@ZnFe_(2)O_(4)’s rigidity,ensuring a reliable service life,but also makes PDA@ZnFe_(2)O_(4)/RSF exhibit excellent catalytic activity and biocompatibility.Therefore,the composite fiber exhibits exceptional mechanical properties and reliable hydrogen peroxide sensing capabilities,making it a promising material for biological and medical applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.62071410 and 62101477)Hunan Provincial Natural Science Foundation(No.2021JJ40542).
文摘The rise in gas leakage incidents underscores the urgent need for advanced gas-sensing platforms with ultra-low concentration detection capability.Sensing gate field effect transistor(FET)gas sensors,renowned for the gas-induced signal amplification without directly exposing the channel to the ambient environment,play a pivotal role in detecting trace-level hazardous gases with high sensitivity and good stability.In this work,carbon nanotubes are employed as the conducting channel,and yttrium oxide(Y_(2)O_(3))is utilized as the gate dielectric layer.Noble metal Pd is incorporated as a sensing gate for hydrogen(H_(2))detection,leveraging its catalytic properties and unique adsorption capability.The fabricated carbon-based FET gas sensor demonstrates a remarkable detection limit of 20×10^(–9) for H_(2) under an air environment,enabling early warning in case of gas leakage.Moreover,the as-prepared sensor exhibited good selectivity,repeatability,and anti-humidity properties.Further experiments elucidate the interaction between H_(2) and sensing electrode under an air/nitrogen environment,providing insights into the underlying oxygen-assisted recoverable sensing mechanism.It is our aspiration for this research to establish a robust experimental foundation for achieving high performance and highly integrated fabrication of trace gas sensors.
基金support from the National Key R&D Program of China(Grant No.2018YFE0118700)the National Natural Science Foundation of China(NSFC No.62174119)+1 种基金the 111 Project(Grant No.B07014)the Foundation for Talent Scientists of Nanchang Institute for Micro-technology of Tianjin University.
文摘Hydrogen is known for its efficient combustion,abundant natural availability,and environmentally friendly characteristics.It is recognized as a promising energy source for the future and is already utilized in various industries,including petrochemicals,electronics,food processing,aerospace,and new energy vehicles.However,challenges arise in the storage and use of hydrogen owing to its tendency to leak,its potential for explosion within a specific concentration range of 4%-75%,and itslow ignition energy requirements.Consequently,there is a demand for hydrogen sensors capable of quickly and accurately detecting low levels of hydrogen leaks.Microelectromechanical systems-based chemiresistive hydrogen sensors offer advantages such as low cost,compact size,low energy consumption,and superior sensing performance,making them a major focus of recent research.This article provides a comprehensive overview and comparison of the sensing principles of various hydrogen sensors,including chemiresistive sensors,electrochemical sensors,thermocatalytic sensors,acoustic sensors,and mechanical sensors.Micro-chemiresistive hydrogen sensors exhibit high sensitivity,low cost,and ease of integration,making them highly promising for practical applications.In response to the challenges encountered in practical applications of chemiresistive hydrogen sensors,such as high operating temperatures and high power consumption,this review explores emerging trends in chemiresistive hydrogen sensor technology from the perspectives of novel materials and activation methods.Finally,it discusses the applications and potential further developments of chemiresistive hydrogen sensors.
基金supported by the National Natural Science Foundation of China under Grant No.50774018
文摘The steel contains a small amount of hydrogen which will escape during the heat treatment.The hydrogen pressure in 16MnRE steel was investigated with a hydrogen sensor,which used SrCe0.95Yb0.05O3-α proton conductor as a solid electrolyte,YHx＋YH2z as a solid state reference electrode and Ni wire as electrode constructing a hydrogen concentration cell,shown as Ni｜YHx＋YH2z ｜SrCe0.95Yb0.05O3-α ｜[H] steel ｜Ni.The response time of sensor is less than 10s.The relational expression of hydrogen partial pressure with temperatures was determined using two shape proton conductors.The results showed the regularity in experimental temperature range,and the hydrogen partial pressure increased as its temperature was raised.
基金supported by National Natural Science Foundation of China (No.21176061)China and Science and Technology Planning Project (2013FJ3023) of Hunan Province in China
文摘The principle, design, construction and performance of the amperometric and potentiometric sensors for measuring the permeation rate of hydrogen through the wall of metal equipment were investigated in order to develop a new type of hydrogen sensor with high accuracy. The transient curves of hydrogen permeation under a given charging condition were employed to evaluate the performance of two types of hydrogen sensors. The relative deviation of the hydrogen concentration detected with two types of sensors under the same condition varied from 3.0% to 13%. The accuracy, response time, reproducibility, and installation were discussed and compared. Response time of the potentiometric sensor （E-sensor） was shorter than that of the amperometric sensor （I-sensor）. Both types of sensors exhibited good reproducibility. Development of I-sensor composed of a kind of proton conductor adhesives or non-fluid electrolytes which contain two functions of high electrical conductivity and a strong adhesion will be a promising prospect in order to measure hydrogen permeation at high temperature.
基金This work was financially support by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for Scientific Research(KAKENHI)(No.20H00297 and Innovative Areas No.JP16H06439)the Cooperative Research Program of Dynamic Alliance for Open Innovations Bridging Human,Environment and Materials in the“Network Joint Research Center for Materials and Devices”.
文摘Hydrogen is a promising renewable energy source for fossil-free transportation and electrical energy generation.However,leaking hydrogen in high-temperature production processes can cause an explosion,which endangers production workers and surrounding areas.To detect leaks early,we used a sensor material based on a wide bandgap aluminum nitride(AlN)that can withstand a high-temperature environment.Three unique AlN morphologies(rod-like,nest-like,and hexagonal plate-like)were synthesized by a direct nitridation method at 1400℃usingγ-AlOOH as a precursor.The gas-sensing performance shows that a hexagonal plate-like morphology exhibited p-type sensing behavior and showed good repeatability as well as the highest response(S=58.7)toward a 750 ppm leak of H2 gas at high temperature(500°C)compared with the rod-like and nest-like morphologies.Furthermore,the hexagonal plate-like morphology showed fast response and recovery times of 40 and 82 s,respectively.The surface facet of the hexagonal morphology of AlN might be energetically favorable for gas adsorption–desorption for enhanced hydrogen detection.
基金The project is sponsored by the Scientific Research Foundation for the Returned 0verseas Chinese Scholars；State Education Ministry；the Zhejiang Natural Science Foundation under Grant No. Y404325.
文摘In this paper,palladium-silver (Pd-Ag) system was studied for hydrogen sensing.Nanofilm of Pd-Ag was fabricated on a porous ceramic substrate through a combination of microfabrication techniques.The electric resistance of the zigzag-shaped microstructure was measured toward hydrogen concentration change.The sensing element demonstrates high sensitivity,fast response and fast recovery to hydrogen.The Pd-Ag film was characterized by scanning electron microscopy (SEM) equipped with X probe to correlate its physical and chemical properties to its sensing performance.The present sensor is very promising for room temperature hydrogen leakage detection and related applications.The temperature effect on the sensing performance of the metal film was also investigated.
文摘Peculiarities of the low-frequency noise spectroscopy of hydrogen gas sensors made on MgFeO4 n-type porous semiconductor covered by the palladium catalytic nanosize particles are investigated. Behavior of the low-frequency noise spectral density and its exponent value from sensitive layer thickness in the frequency range 2 - 300 Hz are analyzed. Sensitivity of the sensor calculated by the noise method is several tenth times higher as compared with the resistive method. It is shown that besides of the well-known applications, noise spectroscopy can be also used for definition of the unknown thickness of gas sensitive layer, for definition of the sensitive layer subsurface role in the formation of the low-frequency noises and for definition of the intensity of trapping-detrapping processes of the gas molecules.
文摘Hydrogen has been recently attracted much attention with respect to high energy-conversion efficiency and low environmental burden. However, hydrogen gas is dangerous due to an explosive gas and a fast combustion rate. Therefore, the development of hydrogen sensor with high accuracy and reliability that can detect hydrogen easily is required. Especially, a flexible hydrogen sensor is useful because it has a high degree of freedom with respect to the shape of location in which the sensor is to be located. A flexible hydrogen sensor—namely, a WO3 thin film formed on a PET film by the sol-gel method using photo irradiation—based on gasochromism of WO3 was developed. By irradiating a thin film, which was prepared by using WO3 precursor solution synthesized by the sol-gel method, with ultraviolet rays, a high-purity WO3 film could be prepared on PET at low temperature. The sensor was structured as a polystyrene (PS) film containing palladium (Pd) laminated on a WO3 film. The WO3 layer was porous, so the PS containing Pd atoms solution penetrated the WO3 layer. WO3 reacted with hydrogen gas and instantly turned blue as the transmittance of the WO3 layer changed. The sensor showed high reactivity even for hydrogen concentration below 4% (1%, 0.5%, 0.25%, and 0.1%), which was the lower limit of hydrogen ignition, and a linear relationship between hydrogen concentration and change in transmittance was found. Moreover, the resistance of the WO3 film significantly and instantaneously changed due to hydrogen-gas exposure, and the hydrogen concentration and resistance change showed a linear relationship. It is therefore possible to quantitatively detect low concentrations of hydrogen by using changes in transmittance and resistance as indices. Since these changes occur selectively under hydrogen at room temperature and normal pressure, they form the basis of a highly sensitive hydrogen sensor. Since the developed sensor is flexible, it has a high degree of freedom with respect to the shape of location in which the sensor is to be
基金National Natural Science Foundation of China(No.51905090)。
文摘Graphene has exceptional electrical,optical and thermal properties,and is widely used to create thinner,lighter and faster sensors.In this study,graphene was fabricated by mechanically exfoliating on the SiO_(2)/Si substrate and the graphene field effect transistor(FET)was prepared by photolithography.Platinum(Pt)particles were doped on the surface of graphene by the hydrazine hydrate reduction method to endow a Pt/graphene sensor with gas-sensing properties.By being tested on a gas detection platform,the characteristics of the electrical(Ⅰ-Ⅴ)curves and resistance response curves were obtained in different hydrogen environments.The results show that the Pt/graphene sensor exhibits a high sensitivity to hydrogen at room temperature,with a resistance response rate of 33.35%at a hydrogen volume fraction of 1.00%.However,the sensitivity lifetime study shows an essential hysteresis in desorption process,which leads to gradually decreases in the resistance response rate.This research provides an improved production method of graphene-based gas sensors,which has a wide range of potential applications in aero-space industry.
基金supported in part by the National Natural Science Foundation of China(Grant No.62025505)in part by the National Science Fund for Distinguished Young Scholars of China(Grant No.62061136002)in part by Deutsche Forschungsgemeinschaft(DFG),Germany(Grant No.448330062).
文摘A novel optical fiber hydrogen sensor based on theπ-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper.The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in theπ-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology.Since the hydrogen sensitivity between the notch and flank wavelengths of theπ-phase-shifted grating is different due to the partial coating only on theπ-phase-shifted grating region,the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper.The hydrogen calibration results show that the sensor shows the good response and repeatability.At the temperature of 20 and℃the hydrogen concentration of 2%,the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm,respectively.
基金financial supports from National Key Research and Development Program of China(2023YFB3209500)National Natural Science Foundation of China(NSFC)(12274052 and 62171076)+1 种基金Fundamental Research Funds for the Central Universities(DUT24ZD203)Bolian Research Funds of Dalian Maritime University and Fundamental Research Funds for the Central Universities(3132024605).
文摘Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.
基金This work is supported by the National Natural Science Foundation of China （61107073, 61107072, and 61290312）, Fundamental Research Funds for the Central Universities （ZYGX2011J002）, Research Fund for the Doctoral Program of Higher Education of China （20110185120020）, Program for Changjiang Scholars and Innovative Research Team in University （PCSIRT, IRT1218）, and the 111 Project （B 14039）.
文摘A fiber-optic Fabry-Perot hydrogen sensor was developed by measuring the fringe contrast changes at different hydrogen concentrations. The experimental results indicated that the sensing performance with the Pd-Y film was better than that with the Pd film. A fringe contrast with a decrease of 0.5 dB was detected with a hydrogen concentration change from 0% to 5.5%. The temperature response of the sensor was also measured.
基金conducted under FRGS Grant:203/PFIZIK/6711197 the support from Universiti Sains Malaysia gratefully acknowledged
文摘In this paper, high-quality nanocrystalline SnO_2 thin film was grown on bare Si(100) substrates by a sol–gel method. A metal–semiconductor–metal gas sensor was fabricated using nanocrystalline SnO_2 thin film and palladium(Pd)metal. The contact between Pd and nanocrystalline SnO_2 film is tunable. Ohmic barrier contact was formed without addition of glycerin, while Schottky contact formed by adding glycerin. Two kinds of sensor devices with Schottky contact were fabricated(Device 1: 8 h, 500 °C; Device 2: 10 h, 400 °C). The room temperature sensitivity for hydrogen(H_2) was120 and 95 % in 1000 ppm H_2, and the low power consumption was 65 and 86 l W for two devices, respectively. At higher temperature of 125 °C, the sensitivity was increased to 195 and 160 %, respectively. The sensing measurements were repeatable at various temperatures(room temperature, 75, 125 °C) for over 50 min. It was found that Device 1 has better sensitivity than Device 2 due to its better crystallinity. These findings indicate that the sensors fabricated on bare Si by adding glycerin to the sol solution have strong ability to detect H_2 gas under different concentrations and temperatures.
文摘The principle, construction and application of two types of electrochemical sensors-amperometric and potentiometric are surveyed. Both types of sensors are very sensitive to changes in temperature. The accuracy of hydrogen measurement depends on both the precision of sensors developed and the reliable technique of installation and security of sensors. The two types of sensors have been used for in-situ determining hydrogen permeated in steels owing to a corrosive reaction, a hydrogen gas circumstance at elevated temperatures and high pressure or also a pretreatment process such as pickling and plating process, etc.
文摘A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.
文摘Hydrogen gas sensor device with simple planar structure based on p^+ silicon substrate with n-type epi-layer was fabricated only by using a lift-off technique of an evaporated metal film.The device consists of Ohmic source and drain electrodes and platinum Schottky gate electrode.This sensor device has a little similar property as FET.Current-voltage characteristics between the source and drain of the device are sensitive to hydrogen gas.The voltage difference between in hydrogen ambient and oxygen ambient is about 2.3 volts for a constant current of 0.9 mA.The device can detect 0.4% hydrogen gas in air.Based on oxidation reaction of hydrogen on the surface of the platinum gate,hydrogen sensitivity of the device changes by the coexisting oxygen concentration.Electrons flow in the buried channel formed between the gate electrode and the p^+n junction.It was confirmed that the gate bias influences the properties.The current-voltage property changes also depending on the wiring method.
基金University of Mazandaran,Babolsar,for their support
文摘The Prussian blue nanoparticles（PBNPs） were prepared by a self-assembly process, on a glassy carbon（GC） electrode modified with a poly（o-phenylenediamine）（Po PD） film. The stepwise fabrication process of PBNPs-modified Po PD/GCE was characterized by scanning electron microscopy（SEM） and electrochemical impedance spectroscopy. The prepared PBNPs showed an average size of 70 nm and a homogeneous distribution on the surface of modified electrodes. The PBNPs/Po PD/GCE showed adequate mechanical, electrochemical stability and good sensitivity in comparison with other PB based H2O2 sensors. The present modified electrode exhibited a linear response for H2O2 reduction over the concentration range of 1–58.22 mmol L ^-1with a detection limit of ca. 0.8 mmol L ^-1（S/N = 3）, and sensitivity of 3187.89 m A（mol L ^-1） ^-1cm ^-2using the amperometric method. This sensor was employed for the H2O2 determination in real sample and also exhibited good interference resistance and selectivity.
基金supported by the National Natural Science Foundation of China(Nos.60808020 and 61078041)the Natural Science Foundation of Tianjin(Nos.16JCQNJC02100,15JCYBJC51700 and 16JCYBJC15400)the National Science and Technology Support(No.2014BAH03F01)
文摘An optical hydrogen sulfide(H_2S) sensor based on wavelength modulation spectroscopy with the second harmonic(2f) corrected by the first harmonic(1f) signal(WMS-2f/1f) is developed using a distributed feedback(DFB) laser emitting at 1.578 μm and a homemade gas cell with 1-m-long optical path length. The novel sensor is constructed by an electrical cabinet and an optical reflecting and receiving end. The DFB laser is employed for targeting a strong H_2S line at 6 336.62 cm^(-1) in the fundamental absorption band of H_2S. The sensor performance, including the minimum detection limit and the stability, can be improved by reducing the laser intensity drift and common mode noise by means of the WMS-2f/1f technique. The experimental results indicate that the linearity and response time of the sensor are 0.999 26 and 6 s(in concentration range of 15.2—45.6 mg/m^3), respectively. The maximum relative deviation for continuous detection(60 min) of 30.4 mg/m^3 H_2S is 0.48% and the minimum detection limit obtained by Allan variance is 79 μg/m^3 with optimal integration time of 32 s. The optical H_2S sensor can be applied to environmental monitoring and industrial production, and it has significance for real-time online detection in many fields.
文摘hydrogen peroxide electrode with 1,1'-dimethylferrocene(DMFc)used as an electron transfer mediator has been described.Using Nafion, DMFc was modified on a glassy carbon electrode(GCE)surface,and horseradish peroxidase(HRP)was then immobiliged on the DMFc-Nafion film,forming a HRp-DMFc-Nafion modi- fied electrode. The chracteristics of the sensor has been shown by cyclic voltam- metry and constant potential measurements,The sensor responds fastly to hydro- gen peroxide,the time required to reach 95%of the steady-state current is less than 50s. The sensor displays a sensitive catalytic current response to hydrogen peroxide and can be operated at a potential range in which the oxidation of common interfering species,such as ascorbic acid and uric acid,does not occur. The sensor is stable for 20 days and its detection limit is 1 μmol/L.
基金supported by Guizhou Provincial Basic Research Program(Natural Science)(ZK[2024]574)Anshun University PhD Fund Project(No.asxybsjj202302)+1 种基金the National Synchrotron Radiation Laboratory(NSRL,Hefei,China)(No.2021-HLS-PT-004163)Shanghai Synchrotron Radiation Facility(SSRF,Shanghai,China)(No.2018-NFPS-PT-002700).
文摘Silk is widely used in the production of high-quality textiles.At the same time,the amount of silk textiles no longer in use and discarded is increasing,resulting in significant waste and pollution.This issue is of great concern in many countries where silk is used.Hydrogen peroxide as a naturally occurring compound is an important indicator of detection in both biology and the environment.This study aims to develop a composite fiber with hydrogen peroxide-sensing properties using discarded silk materials.To achieve this goal,firstly,polydopamine(PDA)was used to encapsulate the ZnFe_(2)O_(4) NPs to achieve the improvement of dispersion,and then regenerated silk fibroin(RSF)and PDA@ZnFe_(2)O_(4)/RSF hybrid fibers are prepared by wet spinning.Research has shown that PDA@ZnFe_(2)O_(4)/RSF demonstrates exceptional sensitivity,selectivity,and stability in detecting hydrogen peroxide,while maintaining high mechanical strength.Furthermore,the complete hybridization of PDA@ZnFe_(2)O_(4) with silk fibroin not only results in the combination of the durability of silk fibroin and PDA@ZnFe_(2)O_(4)’s rigidity,ensuring a reliable service life,but also makes PDA@ZnFe_(2)O_(4)/RSF exhibit excellent catalytic activity and biocompatibility.Therefore,the composite fiber exhibits exceptional mechanical properties and reliable hydrogen peroxide sensing capabilities,making it a promising material for biological and medical applications.
