A Review of Palladium-Based Fiber-Optic Sensors for Molecular Hydrogen Detection

Silva, Susana; Coelho, L.; Frazão, Orlando; Santos, J. L.; Malcata, F. Xavier

doi:10.1109/jsen.2011.2138130

Cited by 119 publications

(83 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, facet mirror designs have a high durability, low footprint, and show good repeatability, along with having a very low fabrication complexity. Some more thorough reviews and comparisons of hydrogen sensors in general can be found in [3,38,39].…”

Section: Fiber Optic Hydrogen Sensorsmentioning

confidence: 99%

Hydrogen Detection Using a Single Palladium Nano-Aperture on a Fiber Tip

McKeown

Goddard

2014

Springer Series in Surface Sciences

View full text Add to dashboard Cite

This chapter discusses the development of fiber optic hydrogen sensors. A motivation for these sensors is given followed by an explanation of the underlying physics of the palladium-hydrogen system. Research results and the strengths and weaknesses of several different fiber optic hydrogen sensor types are discussed. Specifically, the Pd fiber mirror, tapered fiber, Fabry-Pérot interferometer, Fiber Bragg grating, and long period grating sensor architectures are reviewed. Next, a new sensor topology that uses a nano-aperture patterned onto the tip of a Pd coated fiber is presented. The nano-aperture enhances sensitivity because it not only confines light tightly to the Pd surface, but it also creates a Fabry-Pérot resonant structure. Thus, the power shifts in transmission and reflection due to hydrogen induced optical and mechanical changes to the Pd film are amplified. Finally, some conclusions and suggestions for future work are given.

show abstract

Section: Fiber Optic Hydrogen Sensorsmentioning

confidence: 99%

Hydrogen Detection Using a Single Palladium Nano-Aperture on a Fiber Tip

McKeown

Goddard

2014

Springer Series in Surface Sciences

View full text Add to dashboard Cite

show abstract

“…A major safety concern with hydrogen is combustibility. Therefore, early leak detection and concentration determination of hydrogen have been areas of intense research [1][2][3] . There are various types of hydrogen sensors that use a wide range of detection mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…When the concentration is below the transition point for the pure β phase, the optical and mechanical properties of the Pd film will recover after hydrogen removal 13,14 . This property makes a Pd film an effective functional layer for optical hydrogen detection 3,31,33 . Pd-coated cantilevers were previously studied as capacitive hydrogen sensors [34][35][36] .…”

Section: Introductionmentioning

confidence: 99%

Realization of palladium-based optomechanical cantilever hydrogen sensor

McKeown

Wang

et al. 2017

Microsyst Nanoeng

View full text Add to dashboard Cite

Hydrogen has attracted attention as an alternative fuel source and as an energy storage medium. However, the flammability of hydrogen at low concentrations makes it a safety concern. Thus, gas concentration measurements are a vital safety issue. Here we present the experimental realization of a palladium thin film cantilever optomechanical hydrogen gas sensor. We measured the instantaneous shape of the cantilever to nanometer-level accuracy using diffraction phase microscopy. Thus, we were able to quantify changes in the curvature of the cantilever as a function of hydrogen concentration and observed that the sensor's minimum detection limit was well below the 250 p.p.m. limit of our test equipment. Using the change in curvature versus the hydrogen curve for calibration, we accurately determined the hydrogen concentrations for a random sequence of exposures. In addition, we calculated the change in film stress as a function of hydrogen concentration and observed a greater sensitivity at lower concentrations.Keywords: hydrogen detection; imaging and sensing; interference microscopy; optomechanics; optical sensors; surface dynamics INTRODUCTIONHydrogen has always been viewed as a promising alternative to fossil fuels, and it can also function as an effective energy storage medium for intermittent energy sources. In addition, hydrogen is used in a range of other industries, including chemical production, metal refining, and food processing. A major safety concern with hydrogen is combustibility. Therefore, early leak detection and concentration determination of hydrogen have been areas of intense research 1-3 . There are various types of hydrogen sensors that use a wide range of detection mechanisms. Lundström et al. 4 proposed metal oxide semiconductor (MOS)-type hydrogen sensors 5 . However, MOS sensors suffer from drawbacks such as premature saturation of detectable hydrogen concentrations and low sensitivity. Other MOS-based devices have been used as hydrogen sensors, such as MOS field-effect transistors (FETs) 6,7 , high electron mobility transistors [8][9][10] , and Schottky diode-type FETs 11,12 . However, these devices require complicated fabrication processes and have high production costs. Optical gas sensors 13-21 not only overcome these disadvantages but also have other unique advantages, such as negligible electrical interference, no risk of ignition from an electrical spark, and the ability to work at high temperatures or in harsh environments.Palladium (Pd) can absorb up to 900 times its own weight in hydrogen gas at room temperature 22 . Compared with platinum 23 , Pd film is more popular because of its lower cost. Pd alloys with Ag, Au, Ni, and WO 3 have also been studied 24-29 because of their improved response time 24,25,27 , sensitivity 28,29 , and durability 26 as a sensing material. The alloys can avoid blistering effects 26 and the α to β phase transition at higher hydrogen concentrations 25,27 .

show abstract

“…These sensing probes employ optical rather than electric power and thus are well suited to the measurement of flammable gases. As a result, a number of optical fiber hydrogen sensors have been proposed, including evanescent-wave absorption devices [6], micromirror optodes [7,8], Mach-Zehnder interferometers [9], surface plasmon resonance (SPR) devices [10] and fiber Bragg gratings (FBG) [10][11][12][13][14][15][16][17][18]. Among these, the FBG hydrogen sensors are most suitable for large scale monitoring since they lend themselves to distributed measurements [11].…”

Section: Introductionmentioning

confidence: 99%

“…The former type monitors the strain caused by the volume change of a Pd or Pd alloy in the presence of hydrogen gas [12][13][14] and can respond to hydrogen under low oxygen concentrations. However, this type has some deficits, including long response times and delamination of the sensor film with exposure to high concentrations of hydrogen [12]. The other type of sensor measures the temperature change of the FBG device induced by an exothermic reaction at a hydrogen sensor film [15].…”

Section: Introductionmentioning

confidence: 99%