Hydrogen Detection Research Articles

Ultrahigh sensitivity of hydrogen detection with a perforated Pd film on a miniature fiber tip

Hydrogen (H2) is a renewable energy gas and an important industrial raw material playing important roles in many fields. However, H2 is colorless, odorless and highly flammable within a wide concentration range. So H2 detection is very important for leakage monitoring especially at low concentration. Here we propose an ultrahigh sensitivity H2 sensor with a perforated palladium (Pd) film on the tip of an optical fiber. The suspended Pd nanohole film forms a Fabry-P é rot (FP) interferometer with a silica capillary fused onto the fiber. Upon H2 adsorption, the Pd nanohole film bends inwards leading to spectral shift of the FP cavity. With the film perforated, its Young’s modulus becomes effectively smaller giving rise to larger spectral shift and higher H2 sensitivity. We experimentally studied the effect of the structural parameters of the holey film on the H2 sensing performance and achieved a H2 detection sensitivity of 7.1 pm/ppm and a detection limit of 1.7 ppm. The sensor also shows good repeatability and gas selectivity and is expected to find applications as optical H2 sensors working at low concentrations.

Impact and Detection of Hydrogen in Metals

AbstractThe widespread use of hydrogen as an energy carrier is considered one of the most important keys to achieving the decarbonization necessary for the energy transition in numerous areas of technology and society. Not least due to the associated contact of metallic components with (pressurized) hydrogen, there is a latent risk of hydrogen-induced cracking (“hydrogen embrittlement”). The cause of damage is the hydrogen absorbed by the material, which is mobile via interstitial lattice diffusion. In high-strength steels with a tensile strength of more than 800 MPa, even very low diffusive hydrogen contents of less than 1 ppm (parts per million) can have a crack-inducing effect. Hence, dedicated, highly accurate analytical and testing methods are required for the detection of hydrogen and its effect on the mechanical properties of metals. This paper summarizes the current state of knowledge regarding hydrogen embrittlement and reviews the analytical, mechanical, and fractographic investigation methods for detecting hydrogen in metals.

Synergistic effects of bimetallic Pd-Au(alloy)/SnO2 nanocomposites for low temperature and selective hydrogen gas sensors

In view of the explosive nature of hydrogen gas, the demand for detection is increasing. Although Pd-based chemiresistive sensors are gaining much attention in hydrogen detection, it is easily oxidized at high temperatures, leading to the deterioration of sensing performance. To address this issue, we synthesized bimetallic Pd-Au alloy nanoparticles (NPs) and mixed them with SnO2 powder for improving the hydrogen sensing performance. The response of the bimetallic Pd-Au(alloy)/SnO2 nanocomposites (NCs) sensor toward 100 ppm hydrogen was 72.78 which is 7 times higher than that of the pure SnO2 sensor at a relatively lower working temperature of 150°C. Furthermore, when compared to other interfering gases, the sensor revealed high selectivity for hydrogen gas. The enhanced hydrogen sensing performance was attributed to the synergistic effect arising from the formation of a heterojunction interface between Pd-Au alloy and SnO2 NPs and the decomposition and absorption of hydrogen molecules by Pd-Au alloy NPs.

Quantitative hydrogen and methane gas sensing via implementing AI based spectral analysis of plasma discharge

In this report we explore the feasibility of a quantitative gas detection system concept based on alternations in spectral emissions of a radio frequency power generated plasma in presence of a target gas. We then proceed with training a deep learning residual network computer vison model with the spectral data obtained from the plasma to be able to perform regressive calculation of the target gas content in the plasma. We explore this concept with hydrogen and methane gas present in the plasma at know quantities to evaluate the applicability of the concept as hydrogen or methane detection system. We will demonstrate that the system is well capable of quantitatively detecting either of the gases efficiently while it is challenging to estimate hydrogen content in presence of methane.

Hydrogen sensing capabilities of highly nanoporous black gold films

Hydrogen sensing is a crucial topic for many industrial and environmental applications regarding the green deal and the use of hydrogen as a next-generation energy source/energy-storage medium. Therefore, many different approaches are being used to find sensitive, reliable and inexpensive devices for hydrogen detection. One such approach is the use of chemiresistive nanostructured materials that provide a large surface area for hydrogen adsorption. In this paper, we present a detailed study of the hydrogen sensing capabilities of highly nanoporous black gold films that show fast response and recovery times (0.5 min) while operating at low temperatures (40 °C). To investigate the sensing properties of black gold, films with different levels of nanoporosity were prepared and tested to a hydrogen concentration in the range of 0.25–0.95 %. Film morphology was characterised by AFM, SEM and XPS. To correctly examine the nanopores and defects in prepared films, Variable Energy Positron Annihilation Spectroscopy (VEPAS) was used. We found that nanoporous black gold is suitable as an active layer of chemiresistor for hydrogen sensing and that its sensitivity is the function of the film nanoporosity. Possible mechanisms of hydrogen-gold interactions are discussed.

Enhancing high sensitive hydrogen detection of Bi2O3 nanoparticle decorated TiO2 nanotubes

An electrochemical anodization technique was used to create a hydrogen gas sensor based on TiO2 nanotubes decorated with bismuth oxide (Bi2O3). Bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) was employed as the source material for Bi2O3. The resulting nanotubes were annealed at 500 °C, revealing an amorphous structure with a mixed phase of rutile and anatase. Platinum (Pt) electrodes, with a thickness of 100 nm, were coated onto the Bi2O3@TiO2/Ti and TiO2/Ti structures for sensor testing. Energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM) were used to examine the structural, morphological, and surface properties of the Bi2O3@TiO2 and TiO2 nanotubes. The hydrogen sensing properties of the Pt/Bi2O3@TiO2/Ti and Pt/TiO2/Ti devices were evaluated at room temperature, with hydrogen concentrations ranging from 1000 ppm to 10 %. The I–V characterization of the sensor devices under 1 % H2 exhibited typical Schottky-type behavior. Remarkably, the Pt/Bi2O3@TiO2/Ti structure demonstrated a sensor response 1 × 107 times higher than that of in a dry air environment when the same voltage was applied under up to 1 % H2 conditions. The uniform dispersion of Bi2O3 nanoparticles throughout the structure contributed to the enhanced sensor response in the presence of H2.

The Pt-interfacial-reaction-based quantitative detection of trace H2 released from palladium hydride in aqueous solutions

Hydrogen gas holds tremendous potential across various domains, encompassing industrial applications, medical usage, and scientific research, among others. The precise and reliable detection of hydrogen gas is of paramount importance to ensure its safe utilization and accurate control of associated reactions, among other considerations. However, conventional approaches for quantitatively detecting H2, such as gas chromatography and hydrogen sensors, primarily focus on gas-phase detection, neglecting the detection of trace amounts of H2 in the liquid phase. This limitation becomes particularly pertinent when employing palladium hydride (PdHx) as a slow-releasing agent of hydrogen for medical purposes, necessitating the quantification of H2 released from PdHx in aqueous solutions, which is not straightforward to accomplish. This study presents a straightforward and convenient electrochemical method for quantifying H2 in an aqueous solution released from PdHx. The proposed method establishes a linear relationship between the theoretical concentration of H2 in the solution and the amount of H2 that reacted on the working electrode. Consequently, by measuring the amount of H2 that reacted on the working electrode in a PdHx dispersion, the actual concentration of H2 can be determined using the established linear relation. Specifically, it was found that the concentration of H2 released by 200 μg/mL PdHx at room temperature was determined to be 0.23 mM. To validate the findings, a simulation of the hydrogen detection reaction was conducted, which exhibited good agreement with the experimental results. The simulation results suggest that the presence of a peak near the primary hydrogen oxidation peak could be attributed to the adsorption of H2 and H+ near the electrode surface, and this effect diminishes with increasing temperature due to the weakening of species adsorption at elevated temperatures. Moreover, this study also demonstrated the quantitative verification of O2 in an aqueous solution using a similar method. The detection of trace amounts of H2 or O2 in aqueous solutions can find applications in determining the actual production of H2 in hydrogen evolution reactions facilitated by molecular catalysts and evaluating the trace amounts of H2 in photocatalysis as a complementary technique to gas chromatography. This methodology holds significant potential for advancing various areas of research.

Rapid detection of hydrogen using narrow bandwidth fiber-optic spectral combs with a low limit of detection.

The all-fiber detection solutions are the key technology to detecting hydrogen leakage in time because of the low explosive limit of the hydrogen-air mixture gas. However, most of the fiber-optic-based hydrogen sensing platforms must disrupt their structure to achieve a special architecture for interacting with the hydrogen. Here, we report a promising non-damaged structure of fiber-optic narrow bandwidth spectral combs, that can be developed to determine the refractive change as low as 10-5 using its cut-off cladding resonance mode. Such high performance of response for the refractive index induces a rapid detection of hydrogen after a proper thickness of palladium was deposited on the device. An average response time of hydrogen of 4 min with a low limit of detection of 348 ppm was achieved. It is demonstrated that these narrow bandwidth fiber-optic resonance combs can be used for gas detection after being combined with functional materials.

Field Effect Transistors With Semiconductor-Sensitized Gate for High-Sensitivity Hydrogen Detection

Field Effect Transistors With Semiconductor-Sensitized Gate for High-Sensitivity Hydrogen Detection

CeO2 nanorods decorated In2O3 nanoparticles for enhanced low temperature detection of hydrogen

Hydrogen (H2) detection sensors based on pure CeO2 nanorods (NRs) and In2O3-loaded CeO2 NRs with different In2O3 contents (5 wt%, 10 wt%, and 15 wt%) were investigated. The crystal phase evolution, morphology features, and response characteristics of the In2O3-loaded CeO2 NRs were analyzed in detail using characteristic techniques. Gas sensing results showed that the In2O3-loaded CeO2 gas sensors exhibited superior H2 sensing performances compared with pure CeO2 NRs under low operating temperature (100 °C). Notably, the gas sensors based on the 10 wt% In2O3-loaded CeO2 nanocomposite showed the most refined performance, with response values of 2.79 and 2.43 times higher than those of the pure CeO2 NRs sensors for 1000 ppm and 4000 ppm H2, respectively. The response values exhibited a linear relationship with the detection concentration. Moreover, the In2O3-loaded CeO2 gas sensor demonstrated enhanced H2 selectivity, good recyclability, and long-term stability. Finally, the improved gas sensing mechanism of the In2O3-loaded CeO2 gas sensor for H2 was also proposed.

Water-assisted hydrogen spillover in Pt nanoparticle-based metal–organic framework composites

Hydrogen spillover is the migration of activated hydrogen atoms from a metal particle onto the surface of catalyst support, which has made significant progress in heterogeneous catalysis. The phenomenon has been well researched on oxide supports, yet its occurrence, detection method and mechanism on non-oxide supports such as metal–organic frameworks (MOFs) remain controversial. Herein, we develop a facile strategy for efficiency enhancement of hydrogen spillover on various MOFs with the aid of water molecules. By encapsulating platinum (Pt) nanoparticles in MOF-801 for activating hydrogen and hydrogenation of C=C in the MOF ligand as activated hydrogen detector, a research platform is built with Pt@MOF-801 to measure the hydrogenation region for quantifying the efficiency and spatial extent of hydrogen spillover. A water-assisted hydrogen spillover path is found with lower migration energy barrier than the traditional spillover path via ligand. The synergy of the two paths explains a significant boost of hydrogen spillover in MOF-801 from imperceptible existence to spanning at least 100-nm-diameter region. Moreover, such strategy shows universality in different MOF and covalent organic framework materials for efficiency promotion of hydrogen spillover and improvement of catalytic activity and antitoxicity, opening up new horizons for catalyst design in porous crystalline materials.

Chemiresistive Gas Sensing using Graphene-Metal Oxide Hybrids.

Chemiresistive sensing lies in its ability to provide fast, accurate, and reliable detection of various gases in a cost-effective and non-invasive manner. In this context, graphene-functionalized metal oxides play crucial role in hydrogen gas sensing. However, a cost-effective, defect-free, and large production schemes of graphene-based sensors are required for industrial applications. This review focuses on graphene-functionalized metal oxide nanostructures designed for gaseous molecules detection, mainly hydrogen gas sensing applications. For the convenience of the reader and to understand the role of graphene-metal oxide hybrids (GMOH) in gas sensing activities, a brief overview of the properties and synthesis routes of graphene and GMOH have been reported in this paper. Metal oxides play an essential role in the GMOH construct for hydrogen gas sensing. Therefore, various metal oxides-decorated GMOH constructs are detailed in this review as gas sensing platforms, particularly for hydrogen detection. Finally, specific directions for future research works and challenges ahead in designing highly selective and sensitive hydrogen gas sensors have been highlighted. As illustrated in this review, understanding of the metal oxides-decorated GMOH constructs is expected to guide ones in developing emerging hybrid nanomaterials that are suitable for hydrogen gas sensing applications.

Sensitivity and selectivity Pt loaded SnO2–Co3O4 gas sensor for hydrogen detection

Here Pt loaded SnO2–Co3O4 composite was fabricated using a hydrothermal method and was applied to gas sensing for the first time. The structure, morphology, surface and gas sensing property of the sensing composites were respectively studied by XRD, SEM, HRTEM (Mapping), BET, XPS and electrochemical workstation. The gas sensing results showed that the response value of 1%Pt loaded SnO2/5%Co3O4 to hydrogen gas was 57.9, which was 9.6 times of pristine SnO2. And the response time of 1%Pt-loaded SnO2/5%Co3O4 to hydrogen was 12 s, which was much faster than that of pristine SnO2. The material also exhibited other excellent sensing performance such as selectivity for detecting H2 gas. Based on the experiments, the improved H2 sensing properties was due to synergistic effect of the spillover effect of Pt element and the formation of p-n junction. This work will provide valid method to fabricate SnO2-based gas sensing materials for real application to detect target gas.

High-performance H2 sensor based on Polyaniline-WO3 nanocomposite for portable batteries and breathomics-diagnosis of irritable bowel syndrome

Low-trace airborne hydrogen (H2) detection at room temperature is a prerequisite in designing sensors for portable batteries and breathomics-based diagnosis of human diseases/disorders. The state-of-the-art H2 sensor engineering is concerned with developing organic-inorganic nanocomposites with controlled morphology and enhanced physicochemical attributes. This unprecedented study reports a chemo-resistive-module H2 sensor based on polyaniline-tungsten oxide (PAni-WO3) nanocomposite fabricated through a facile and economic one-pot polymerization route. The morphological and structural analysis revealed the formation of nanocomposite consisting of WO3 nanorods (∼100 nm diameter) dispersed in the PAni matrix consists of particles with size around 200 nm. The PAni-WO3 chemiresistor exhibited a 5-fold enhanced performance towards one ppm of H2 at room temperature compared to pristine WO3 nanorods/PAni. It demonstrated high performance for room temperature H2 detection in terms of low detection limit (1 ppm), high sensitivity, prompt response, fast recovery, and high repeatability. Besides, the fabricated sensor is highly selective and stable for H2 monitoring in capricious environmental conditions (in varying humidity, temperature and interfering analytes). The well-engineered nanocomposite system possessing rational morphology has latent for real-time monitoring of low-trace human breath-borne H2 for non-invasive irritable bowel syndrome (IBS) diagnosis and for sensing leaks in portable batteries, hydrogen production and storage industries, and environmental monitoring.

2% Transmitted Electrochromic Films by Hydrogen Adsorption

Hydrogen adsorption in WO3 thin films is known to cause the change of color of the films. Due to its high sensitivity, chemical stability as well as biocompatibility, the WO3 offers itself as an efficient hydrogen sensor, especially for detection of hydrogen in humid environments. In this paper we report the preparation and characterization of WO3 electrochoromic thin films prepared on ITO substrates by thermal evaporation synthesis. These films show significant decreases in transparency from over 92% to as low as 2% at an applied bias of −0.7 V. Structure as well as the effect of annealing temperature on the structure and properties of the films are also studied. The changes of optical band gap and the role of hydrogen in coloration process are also discussed.

Enhancing Neutral Hydrogen (HI) Detection in Galaxies through Optimized Matched Filter Analysis

Neutral Hydrogen (HI) is a fundamental component in the composition of galaxies, providing crucial insights into their structure and dynamics. In this research, we propose a novel approach to improve the detection of H1 spectral lines in radio telescope data by employing a matched filter algorithm. The algorithm capitalizes on the convolution of a template function, optimized using the "Busy" function that defines the line profile properties, with a randomly generated H1 peak. This H1 peak is subsequently embedded within noisy data, accounting for the effects of telescope measurements, such as thermal broadening and radio-frequency interference. The incorporation of the Voigt profile in the noise generation ensures a realistic representation of these effects. Through comprehensive analysis, we demonstrate that a matched filter with a multi-layered convolution scheme yields the highest efficiency in recovering H1 peaks. The effectiveness of peak recovery is shown to be influenced by the injected noise profiles, allowing for a direct comparison of the matched filter’s performance concerning the Integrated and Peak Signal to Noise ratios. This research contributes to the advancement of observational techniques in astrophysics and deepens our understanding of the distribution and properties of Neutral Hydrogen in galaxies. It represents the first such exploration of this technique in the context of the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD), which is under construction at the Dominion Radio Astronomy Observatory in Penticton, BC and which will survey the HI sky more broadly and deeply than has been previously possible.

Anatase TiO2 aerogel with high specific surface areas and porous network structures for ultra-fast response hydrogen sensor

To better ensure the safe preparation, storage, transportation, and use of hydrogen, it is critical to find a convenient and effective method to monitor requests. In this study, an excellent hydrogen gas sensor based on the TiO2 aerogel structure with a high specific surface area has been successfully fabricated. In addition, we have obtained TiO2 aerogel with anatase crystal form and rutile crystal form through high-temperature crystallization to further explore the influence of TiO2 nanoparticles and TiO2 aerogel crystal form on the performance of hydrogen sensors. The results show that the sensitivity of anatase TiO2 aerogel hydrogen sensor to 100 ppm H2 at 450 °C is 3.1271, higher than TiO2 nanoparticles (1.4942), amorphous TiO2 aerogel (2.1796) and rutile TiO2 aerogel hydrogen sensor (2.8464), and it exhibits ultra-rapid response recovery characteristics, with a response time of 4 s and a recovery time of 29 s, respectively. Besides, the sensitivity of anatase TiO2 aerogel hydrogen sensor to 100 ppm H2 is twice that of 100 ppm ammonia (1.5668), 2.5 times that of 100 ppm methanol (1.2731), and 1.1 times that of 100 ppm ethanol, showing that anatase TiO2 aerogel has good selectivity in a complex gas environment. The 30 days repeatability test shows that the anatase TiO2 aerogel hydrogen sensor has good stability and linearity (100–1000 ppm H2 concentration). Finally, this work proposes a hydrogen sensing model, which is used to describe the hydrogen sensing mechanism of TiO2 aerogel, indicating that the high specific surface area and high porosity of TiO2 aerogel play an important role in hydrogen detection. Hydrogen sensors based on TiO2 aerogel are rarely reported at present, and this work has an important reference and guidance role for the future in-depth industrial research of hydrogen sensors.

The hydrogen sensing capability of zinc oxide-containing sensors: Modeling by the general regression artificial neural network

This research applies general regression (GR) neural networks to model the hydrogen sensing capability of pure zinc oxide (ZnO) and ZnO nanocomposites containing different additives. The sensor's topology/composition, temperature, and hydrogen concentration in the atmosphere are the independent features of the GR models. Sensitivity analysis approves that the Gaussian spread value must adjust to 23.5 × 10−6 to achieve the most accurate predictions. This model forecasts 297 actual responses of ten ZnO-containing sensors with mean absolute error, relative absolute error, and regression coefficient of 0.29, 1.56%, and 0.9977, respectively. These prediction accuracies are better than those obtained by cascade feedforward, radial basis, Elman recurrent, and multilayer perceptron neural networks. The relevancy test shows that the sensor's hydrogen detection ability improves with the sensor geometry and ZnO additive dose. ZnO–Co3O4 is the best sensor composition to detect even low hydrogen concentrations. Also, the nanowire and nanofiber are the best sensor topologies for the considered task.

Quantitative risk assessment of China's first liquid hydrogen refueling station.

Hydrogen refueling stations (HRSs) are among the most important infrastructures for fuel cell vehicles. However, the safety issue of HRSs has become a key constraint to the wide application and development of hydrogen energy. This article presents a quantitative risk assessment of the first liquid HRS (LHRS) in China and conducts a comprehensive assessment in terms of both individual (IR) and societal risks (SRs). The results showed that both the IRs and SRs related to the LHRS exceeded the risk acceptance criteria. The rupture of the flexible hose of the dispenser and the leak from the compressor are the main contributors to these risks. On the other hand, implementing appropriate mitigation measures on the level of the LHRS dispenser and compressor, including the addition of breakaway couplings in the flexible hose of the dispenser, the installation of hydrogen detection sensors, the arrangement of automatic and manual emergency shutdown buttons, and the elevation of the compressor, is capable of reducing the risk of the LHRS to be within the risk acceptance criteria.

Revolutionizing n‐type Co3O4 Nanowire for Hydrogen Gas Sensing

This study presents conductometric sensors based on Co3O4 nanowires for hydrogen detection at ppb levels. The nanowires are synthesized through thermal oxidation of a 50 nm cobalt layer, exhibiting diameters between 6–50 nm and lengths of 1–5 μm, primarily growing along the (311) direction of spinal Co3O4. Raman investigation reveals five characteristic peaks at 195, 482, 521, 620, and 692 cm−1, corresponding to symmetric phonon modes of crystalline Co3O4. Electron paramagnetic resonance measurements confirm the presence of a ferromagnetic phase, attributed to incomplete cobalt oxidation, which disappears after 8 h of thermal aging at 400 °C. Conductometry measurements are performed in the temperature range of 300–500 °C. At temperatures above 300 °C, sensors exhibit abnormal n‐type semiconducting behavior due to lattice oxygen's involvement in the hydrogen sensing mechanism. Operating at 450 °C in dry air, the sensor shows a higher 232% response to 100 ppm H2 compared to ethanol, acetone, methane, carbon monoxide, and nitrogen dioxide. Remarkably, the sensor maintains a consistent conductance baseline even under high humidity (90%) for 25 d, with three‐cycle repeatability. This distinctive gas‐sensing capability is attributed to the catalytic activity and elevated operating temperature.