Transition metal oxides covered Pd film for optical H2 gas detection

Maciak, E.; Opilski, Z.

doi:10.1016/j.tsf.2007.03.022

Cited by 69 publications

(25 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At very low concentrations of these gases they are usually preconcentrated to obtain a low detection limit. Various methods have been developed to detect these gases [1,2]. The sensor using the propagation of Rayleigh surface acoustic waves (SAW) containing a suitably chosen chemically sensitive layer is adequate for detecting low concentrations of gases.…”

Section: Introductionmentioning

confidence: 99%

SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

Hejczyk¹,

Urbańczyk²,

Wituła³

et al. 2012

Bulletin of the Polish Academy of Sciences: Technical Sciences

Self Cite

View full text Add to dashboard Cite

Abstract. The paper presents the results of numerical analyses of the SAW gas sensor in the steady and non-steady state. The effect of SAW velocity changes vs. the surface electrical conductivity of the sensing layer is predicted. The conductivity of the porous sensing layer above the piezoelectric waveguide depends on the profile of the diffused gas molecule concentration inside the layer. Knudsen's model of gas diffusion was used. Numerical results for the gases CH4, C2H4, C3H8, C6H6 in the steady state and CH4 in the non-steady state in the WO3 sensing layer have been shown. The results of numerical analyzes allow to select the sensor design conditions, including the morphology of the sensor layer, its thickness and operating temperature. Some numerical results were verified in experimental studies concerning methane.

show abstract

Section: Introductionmentioning

confidence: 99%

SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

Hejczyk¹,

Urbańczyk²,

Wituła³

et al. 2012

Bulletin of the Polish Academy of Sciences: Technical Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, multilayer structures, especially layered nanostructures, have been used extensively to improve the sensitivity and reliability of conventional chemical and biological sensors [1][2][3][4][5][6][7][8][9][10][11][12]. For instance, thin single films of Pd and WO 3 do not ensure a sufficient sensitivity towards hydrogen molecules [5,13].…”

Section: Introductionmentioning

confidence: 99%

“…It also increases the response and decreases the maximum operating temperature of the sensor. In the case of sensing H 2 and NO 2 , the modification of metal oxides [8][9][10] (especially WO 3 ) by metal additives such as Pt, Pd, or Au by applying different techniques intensive investigations are under way. It is known that the sensitivity of gas depends on the large surface area and porosity, both of which are affected by the preparation method.…”

Section: Introductionmentioning

confidence: 99%

Layered thin film nanostructures of Pd/WO3-x as resistance gas sensors

Urbańczyk¹,

Maciak²,

Gut³

et al. 2011

Bulletin of the Polish Academy of Sciences: Technical Sciences

Self Cite

View full text Add to dashboard Cite

Abstract. Layered nanostructures of tungsten trioxide WO3-x about 62 nm thick, with a very thin film of palladium (about 3.3 nm) on the top, have been studied for gas-sensing application at temperatures 50• C and 120-130 • C and low NO2 and NH3 concentrations in 6%, 30% or 45% relative humidity in the air. Thin film WO3-x nanostructures were obtained by vacuum deposition on a common Si-SiO2 substrate at room temperature and 120• C. The palladium was coated by vacuum evaporation at room temperature and 4 · 10 −6 mbar on WO3-x layers obtained at two different substrate temperatures. The average rate of growth of the films, controlled by a QCM, was 0.1-0.2 nm/s. A multi-channel (four-channel interdigital gold electrodes) planar resistance gas sensor structure was used in the experiments. The surface of the nanostructures was characterized by means of the AFM method. Good sensor results have been observed at these layered nanostructures with an increasing resistance for NO2 molecules and decreasing resistance for NH3 molecules in a humid air atmosphere. The interaction and recovery speed were higher in the case of the nanostructure obtained at room temperature.

show abstract

“…Experimental results and numerical simulation show the training method available, a linear precision of 0. 1% for the optical hydrogen sensor is achieved.Hydrogen gas detection in different measuring environments has recently become a very important problem [1] , lots of efforts have been made to develop high-performance hydrogen sensors with safety and longer life, optical sensors and especially fiber optic sensor technology provide opportunities for applications of optical sensors. Most of the optical fiber sensors use palladium (Pd) film as transducer to detect the concentration of hydrogen.…”

mentioning

confidence: 99%

“…The Pd/Ag alloy could overcome the problem of hydrogen embrittlement. So far, Pd/Ag is perhaps the mostly studied alloy for hydrogen sensing [1] . Wang Min fabricated a zigzag-shaped microstructure of Pd-Ag plated on alumina substrate, the sensing performance of the mixed metal film is much better than that of pure palladium film [2] .…”

mentioning

confidence: 99%

An optical fiber hydrogen sensor with Pd/Ag film

Cui

Chen

Zhang

2009

Optoelectron. Lett.

View full text Add to dashboard Cite

A 20 nanometer palladium-silver (Pd/Ag) ultra-thin film was used for hydrogen gas sensing. The atomic ratio of Pd: Ag was 3:1, the thin film was evaporated on the optical glass, the Pd/Ag alloy could increase the life and provide the stability of the sensing film. The artificial neutral network was used for processing the data collected from the optical fiber bundle hydrogen sensor, which could enhance the measuring accuracy, at the same time, the intrinsic and extrinsic influences were eliminated mainly. Experimental results and numerical simulation show the training method available, a linear precision of 0. 1% for the optical hydrogen sensor is achieved.Hydrogen gas detection in different measuring environments has recently become a very important problem [1] , lots of efforts have been made to develop high-performance hydrogen sensors with safety and longer life, optical sensors and especially fiber optic sensor technology provide opportunities for applications of optical sensors. Most of the optical fiber sensors use palladium (Pd) film as transducer to detect the concentration of hydrogen. Nonetheless, although pure palladium sensors could provide the good hydrogen sensitivity, there are some drawbacks associated with pure palladium. During the process of absorption and adsorption in hydrogen, pure palladium film suffers the embrittlement phenomenon, the morphology of pure palladium undergoes the phase transformations, and the process is irreversible. After several cycle of exposure to hydrogen, the palladium breaks off from the substrate. So in order to overcome the problem, a great of experiment reports introduce other metals to form palladium alloy. The Pd/Ag alloy could overcome the problem of hydrogen embrittlement. So far, Pd/Ag is perhaps the mostly studied alloy for hydrogen sensing [1] . Wang Min fabricated a zigzag-shaped microstructure of Pd-Ag plated on alumina substrate, the sensing performance of the mixed metal film is much better than that of pure palladium film [2] . In this paper we adopt 20 nm Pd 75 Ag 25 ultrathin films evaporated on the float glass substrates in the optical fiber bundle sensor to overcome the well-known problem of hydrogen embrittlement.The optical fiber sensor is affected by the intrinsic and extrinsic influences, so the optical hydrogen sensor has the characteristics of non-linearization in the whole output process. The paper presents a key technology-artificial neural network (ANN) to process the output signal from the sensor probe, ANN enhances the detection accuracy and adjusts the output non-linearity in the hydrogen sensor.The preparation of Pd/Ag alloy membranes is carried out in a commercial magnetron sputtering machine (FJL560) equipped with dc and rf power sources and adjustable substrate stage(with heating capability up to 400 o C) . Fig.1 is a schematic representation of the magnetron sputtering deposition unit. Before actual deposition, pre-sputtering is done Fig.1 Schematic representation of magnetron sputtering deposition system

show abstract

Transition metal oxides covered Pd film for optical H2 gas detection

Cited by 69 publications

References 10 publications

SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

SAW sensor for detection of hydrocarbons. Numerical analysis and experimental results

Layered thin film nanostructures of Pd/WO3-x as resistance gas sensors

An optical fiber hydrogen sensor with Pd/Ag film

Contact Info

Product

Resources

About