Sub-second and ppm-level optical sensing of hydrogen using templated control of nano-hydride geometry and composition

Abstract

The use of hydrogen as a clean and renewable alternative to fossil fuels requires a suite of flammability mitigating technologies, particularly robust sensors for hydrogen leak detection and concentration monitoring. To this end, we have developed a class of lightweight optical hydrogen sensors based on a metasurface of Pd nano-patchy particle arrays, which fulfills the increasing requirements of a safe hydrogen fuel sensing system with no risk of sparking. The structure of the optical sensor is readily nano-engineered to yield extraordinarily rapid response to hydrogen gas (<3 s at 1 mbar H2) with a high degree of accuracy (<5%). By incorporating 20% Ag, Au or Co, the sensing performances of the Pd-alloy sensor are significantly enhanced, especially for the Pd80Co20 sensor whose optical response time at 1 mbar of H2 is just ~0.85 s, while preserving the excellent accuracy (<2.5%), limit of detection (2.5 ppm), and robustness against aging, temperature, and interfering gases. The superior performance of our sensor places it among the fastest and most sensitive optical hydrogen sensors.

Recent Development in Nanoconfined Hydrides for Energy Storage

“…This method relies on cycling the hydride under a flowing gas of constant hydrogen partial pressure, and the TGA curves are further analyzed using the van't Hoff equation to obtain the absorption/desorption enthalpies, which in the case of VTiCr-catalyzed Mg/MgH 2 materials, showed good agreement with traditional PCT results [34]. Other recent research established a nano-Pd patched surface of Pd 80 Co 20 to afford one of the most sensitive optical hydrogen sensors (fast response of <3 s, high accuracy of <5%, and very low limit of detection of 2.5 ppm) [35]. Employing interpretable machine learning could also help formulate general design principles for intermetallic hydride-based systems being used to validate limited data from the HydPARK experimental metal hydride database and stressing the recommendation for experimental groups to report ∆H, ∆S, P eq , T and V cell [27].…”

Pd80Co20Nanohole Arrays Coated with Poly(methyl methacrylate) for High-Speed Hydrogen Sensing with a Part-per-Billion Detection Limit

“…Such complex electron transport causes the reduction in the response time in the CHA 300 in comparison to the CHA 450 sensor. It should be noted that while the large SVR of the hole array structures is important for the sensing performance of both electrical sensors and optical sensors, the large material coverage and strong plasmonic property of the structures are necessary to obtain high-sensing performance in the optical sensors. , In general, the sensitivity of the sensor device as a function of H 2 gas pressure is defined as where R (H 2 ) and R (0) are resistances of the device with and without H 2 gas, respectively. The commonly used response time, t 80 , for the electric sensors is defined as the elapsed time from the baseline resistance to 80% of the saturation value, Δ R , and the release time t 20 is defined as the elapsed time from the saturated resistance down by 80% of Δ R to the resistance that is equal to 20% of Δ R (see Figure a) .…”

“…First, the plateau region upon (de)­hydrogenation of the Pd-Co-based sensor occurs at very high H 2 pressures (∼1 bar), allowing for high accuracy sensing readout spanning more than 5 orders of H 2 concentration/pressure. Second, our recent optical measurement shows that the response time upon hydrogenation in magnetic hydrides is an order of magnitude faster than that in the nonmagnetic alloys such as Pd-Au and Pd-Ag under the same conditions . This superior performance is likely related to a greater metal–hydrogen bond strength in magnetic materials, which could facilitate dissociative chemisorption of H 2 .…”

Ultrafast Metal Oxide Reduction at Pd/PdO2 Interface Enables One-Second Hydrogen Gas Detection Under Ambient Conditions

“…4 Only a few H2 sensors have been reported to respond to 4% H2 within 1 s (Table 1). [5][6][7][8][9][10][11][12][13][14][15] These sensors can be generally summarized as the following two types: nanogap and plasmonic. For the nanogap sensors, there are nanoscopic gaps in the Pd sensing material.…”

“…When the nanogaps are sufficiently small (< 50 nm), tresponse can be as short as 75 ms. 8 For the plasmonic sensors, the sensor response arises from the shift of the localized surface plasmon resonance peak of Pd-based nanoarchitectures upon H2 absorption by Pd. Their fast response was achieved by tailoring the volume-to-surface ratio in concert with reducing the apparent activation energy for H2 absorption by engineering the metal-polymer coating interface 10,11 and the sensing material composition 5,10,13,14 . However, in these prior works, the 1-s response time was achieved either in an inert gas environment (e.g., N2 and Ar) or under vacuum, not in the ambient air as required by the DOE.…”