Sensitive Hydrogen Gas Sensor Research Articles

Pd Nanoparticles Decorated Hollow TiO2 Nanospheres for Highly Sensitive and Selective UV-Assisted Hydrogen Gas Sensors

Pd Nanoparticles Decorated Hollow TiO₂ Nanospheres for Highly Sensitive and Selective UV-Assisted Hydrogen Gas Sensors

Room temperature hydrogen gas sensor based on Pd decorated bridging GaN nanowires

A highly sensitive and low-power consumption hydrogen (H2) gas sensor based on palladium nanoparticles (Pd NPs) decorated bridging GaN nanowires (NWs) has been fabricated, which can be used for H2 detection at room temperature (RT). The bridging GaN NWs growth across the deep trench of GaN coated sapphire substrate were prepared by Metal-organic Chemical Vapor Deposition (MOCVD), and Pd NPs were deposited on the surface of GaN NWs using magnetron sputtering. The characterizations of the structure and morphology of Pd-GaN NWs indicated that the Pd NPs were successfully loaded on the surface of GaN NWs. The sensors with different Pd thickness (2 nm, 5 nm, 10 nm, and 15 nm) were measured at RT (∼ 25 ℃), with H2 concentrations varying from 1 to 10,000 ppm. When the Pd thickness is 10 nm, the H2 response reaches its maximum, has a fast response time (∼3 s toward 10,000 ppm H2) and a low detection limit (LOD) of 42.2 ppb H2. Moreover, the sensor has excellent repeatability, superior H2 selectivity, relatively good humidity-tolerant and long-term stability. In addition, H2 sensing characteristics at different self-heating power (1.9 mW, 6.6 mW, 18.4 mW, and 36.1 mW) were also measured, and found that the H2 response increased with the increase of self-heating power. The fabricated H2 sensor with low-power consumption (without heater or illumination) have a wide application in portable device or Internet of Things (IoT) system.

Characteristics of highly sensitive hydrogen gas sensor based on Pt-SiO2/Si microring resonator

A hydrogen gas sensor based on a silicon microring resonator (MRR) with a Pt–SiO2 thin film as a hydrogen-sensitive film is proposed and investigated to realize a high-sensitivity hydrogen sensor. The sensor detects hydrogen on the basis of the resonant wavelength shift caused by the reaction heat generated in the Pt–SiO2 film. In the hydrogen exposure measurement, resonant wavelength shifts of approximately 5.0 and 2.4 nm were observed at hydrogen concentrations of 4.0 and 0.4 vol%, respectively, showing the high sensitivity of the proposed sensor. In addition, an MRR sensor with an upper Al2O3 cladding layer is proposed and its higher sensitivity is theoretically demonstrated.

Optimizing coverage of palladium nanoparticles for a highly sensitive hydrogen gas sensor based on nanogaps via spray-deposition

Optimizing coverage of palladium nanoparticles for a highly sensitive hydrogen gas sensor based on nanogaps via spray-deposition

Preparation of ultra-sensitive and highly specific miniature hydrogen sensors by <i>in situ</i> synthesis methods

Hydrogen, as one of the most well-developed green energy materials, has played an important role in industrial development, human production and life, and the treatment of diseases in recent years. Hydrogen sensor is an important safety monitoring equipment in chemical production. Developing long-term and efficient hydrogen gas sensor for real-time monitoring has become increasingly important and urgent. Hydrogen, as one of the main combustible gases present in the petrochemical production process, is of great research significance and challenging in meeting the need of cycling gas identification and highly sensitive detection. Therefore, it is of great practical value to develop the low-cost, low-power and highly sensitive miniature hydrogen gas sensors . In this work, a gold-doped tin dioxide nanostructured ultra-sensitive and highly specific micro-nanosensor is obtained based on the in-situ synthesis of micro-hot plates. It is shown that the sensitivity of this nanosensor is as high as 100 for hydrogen at 50 ppm, and the sensitivity of ethanol, an important interference gas, is only 1/22 of that of hydrogen at the same concentration, which has an obvious suppression effect. For the same concentration of carbon monoxide, methane and other interference gases do not show any response. XPS characterization shows that the defective oxygen ratio of the material is the main reason for the ultra-sensitivity of the sensor. Meanwhile, in this study, the precursor solution of gold-doped tin dioxide is prepared by using chloroauric acid and tin tetrachloride crystals as raw materials; the nanosized morphology structure is prepared by templating the generation of sensitive materials using polystyrene microspheres; the in-situ synthesis method is realized by applying a voltage to the calcination of a micro hot plate. Through this nanoscale templating in-situ heating method, a gold-loaded tin dioxide nanosensor is prepared. Note that the template assisted in-situ grown <inline-formula><tex-math id="M5">\begin{document}$ {\mathrm{A}}{\mathrm{u}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M5.png"/></alternatives></inline-formula> loaded Tin Oxide nano sensor is abbreviated as <inline-formula><tex-math id="M6">\begin{document}$ {\mathrm{T}}{\mathrm{I}}{\mathrm{S}}\text{-}{\mathrm{Au}}\text{-}{{\mathrm{S}}{\mathrm{n}}{\mathrm{O}}}_{2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M6.png"/></alternatives></inline-formula> Sensor . In order to illustrate the sensing mechanism, we analyze the elemental compositions, and the results show that under the condition of the high defective oxygen content, the in-situ heating method of templated preparation of <inline-formula><tex-math id="M7">\begin{document}$ {\mathrm{A}}{\mathrm{u}}\text{-}{{\mathrm{S}}{\mathrm{n}}{\mathrm{O}}}_{2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231265_M7.png"/></alternatives></inline-formula> nano-sensor containing arrays of polystyrene spheres becomes an important reason for the ultra-sensitivity to hydrogen, high specificity, and the suppression of the important interfering gas, ethanol. Moreover, the in situ preparation method can be flexibly and scalably used to prepare high-performance miniaturized gas sensors with a variety of hollow-sphere nanostructured metal oxides, in order to obtain excellent sensitivity and adjustable selectivity.

Catalytic synergy of WS2-anchored PdSe2 for highly sensitive hydrogen gas sensor.

Hydrogen (H2) is widely used in industrial processes and is one of the well-known choices for storage of renewable energy. H2 detection has become crucial for safety in manufacturing, storage, and transportation due to its strong explosivity. To overcome the issue of explosion, there is a need for highly selective and sensitive H2 sensors that can function at low temperatures. In this research, we have adequately fabricated an unreported van der Waals (vdWs) PdSe2/WS2 heterostructure, which exhibits exceptional properties as a H2 sensor. The formation of these heterostructure devices involves the direct selenization process using chemical vapor deposition (CVD) of Pd films that have been deposited on the substrate of SiO2/Si by DC sputtering, followed by drop casting of WS2 nanoparticles prepared by a hydrothermal method onto device substrates including pre-patterned electrodes. The confirmation of the heterostructure has been done through the utilization of powder X-ray diffraction (XRD), depth-dependent X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FE-SEM) techniques. Also, the average roughness of thin films is decided by Atomic Force Microscopy (AFM). The comprehensive research shows that the PdSe2/WS2 heterostructure-based sensor produces a response that is equivalent to 67.4% towards 50 ppm H2 at 100 °C. The response could be a result of the heterostructure effect and the superior selectivity for H2 gas in contrast to other gases, including NO2, CH4, CO and CO2, suggesting tremendous potential for H2 detection. Significantly, the sensor exhibits fast response and a recovery time of 31.5 s and 136.6 s, respectively. Moreover, the explanation of the improvement in gas sensitivity was suggested by exploiting the energy band positioning of the PdSe2/WS2 heterostructure, along with a detailed study of variations in the surface potential. This study has the potential to provide a road map for the advancement of gas sensors utilizing two-dimensional (2D) vdWs heterostructures, which exhibit superior performance at low temperatures.

Fabrication and characterization of highly responsive hydrogen sensor based on Fe2O3:ZnO nanostructured thin film

This work aimed to manufacture a highly sensitive hydrogen gas sensor based on Fe2O3:ZnO thin film. The Fe2O3:ZnO based sputtering target was synthesized by a solid-state synthesis method. Gas-sensitive thin films were deposited onto the alumina substrate by the high-frequency (RF) magnetron sputtering method. The thickness of the sensing film was measured and the morphology of the sensing layers was studied. The Fe2O3:ZnO sensor showed the highest hydrogen gas response at 100 ᵒC and the operating temperature of 150 ᵒC was selected as the optimum working temperature. The sensor showed sensitivity even to extremely low concentrations of hydrogen (100 ppm), where the response was 4.6. The sensing parameters of the fabricated sensor confirm that the Fe2O3:ZnO material may become an excellent nanostructure for the detection of low concentrations of hydrogen.

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.

Highly Sensitive and Selective Hydrogen Gas Sensor with Humidity Tolerance Using Pd-Capped SnO2 Thin Films of Various Thicknesses

Detecting and identifying hydrogen gas leakage before a potential disaster is a critical safety concern. To address this issue, a low-cost and simple-design sensor is required with high response and fast sensing time, capable of detecting hydrogen gas even at low concentrations of 5–500 ppm. This study investigates the use of magnetron-sputtered SnO2 thin films with palladium as a catalytic layer to achieve better sensing output. The developed Pd-caped SnO2 thin film sensors showed increased sensitivity with increasing thickness, up to 246.1 nm at an operating temperature of 250 °C. The sensor with a thickness of 246.1 nm exhibited excellent selectivity for H2 gas, even in humid conditions, and was able to distinguish it from other gases such as CO, NH3, and NO2. The sensor demonstrated high response (99%) with a response/recovery time of 58 s/35 s for (5–500 ppm) hydrogen gas. The sensor showed linear response to H2 gas concentration variation (5–500 ppm) at 250 °C. The sensor was found to be mechanically stable even after 60 days in a high-humidity environment. The LOD of sensor was 151.6 ppb, making it a suitable candidate for applied sensing applications. The Pd-caped SnO2 thin film sensor with thickness of ~245 nm could potentially improve the safety of hydrogen gas handling.

Investigation of palladium gated polarity controllable FET as a highly sensitive and robust hydrogen gas sensor

AbstractThe paper investigates the design and performance of a novel palladium gated‐polarity controllable Field Effect Transistor (FET) (PC‐FET) for hydrogen gas sensing applications. In the present work, catalytic sensing metal gate (palladium) is chosen as control gate (CG) and hydrogen gas molecules are exposed on the region controlled by CG. A compact analytical model has been derived for PC‐FET based sensor and the performance of the proposed gas sensor has been examined in terms of energy band profile, surface potential, electric field, transfer characteristics and transconductance and the derived analytical results are verified using TCAD simulated results. Furthermore, the sensitivity metrics such as threshold voltage sensitivity, drain current sensitivity, transconductance sensitivity and ION/OFF sensitivity have also been extensively investigated for both modes of proposed sensor for a wide range of pressure that is, 10−14–10−8 Torr.

Improvement of hydrogen detection sensitivity of palladium film by in-plane compressive plastic deformation and application to hydrogen gas sensor

The hydrogen energy, which is environmentally friendly and does not emit carbon dioxide, has been attracting attention as an alternative fuel to the fossil fuel. In the shift to a hydrogen energy society, the highly sensitive hydrogen gas sensor has been required for the storage and management of hydrogen gas. In this study, we propose a film deposition method to induce the in-plane plastic deformation in the thin film and apply it to a hydrogen gas sensor, where the palladium film formed by this method is deposited on a thin quartz resonator. It is found that the sensor chip with the plastically deformed palladium film is about 1.5 times more sensitive than the conventional sensor chip and has high-speed response. The developed sensor is a novel device that can be used in an oxygen-free environment without any temperature compensation and constant heating.

First principles study of Rh-doped SnO2 for highly sensitive and selective hydrogen detection

Tin dioxide is a low-cost and efficient material with large potential in applications of hydrogen detection. Doping metals in SnO2 is a solution to further improve its electrical performance, however, atomic-scale understanding of detection mechanism of doped SnO2 is very limited. In this work, first principles and molecular dynamics method are applied to investigate adsorption properties and diffusion effects of CH4, CO2, H2, N2 on Rh-doped SnO2. By calculating adsorption energy, adsorption distance, charge density difference, density of states, it is concluded that Rh-SnO2 shows a strong sensing characteristics towards H2, which is consistent with experiment result. After adsorption of H2, the main energy bands of DOS shift to a lower level of energy, and the Fermi level move to higher level of energy. H2 shows a strong chemical adsorption effect on Rh-SnO2, while CH4, CO2 and N2 only present weak physical adsorption on Rh-SnO2. Furthermore, the diffusion of H2 in Rh-SnO2 is easier than those of other gases. Our study provides a fundamental and new perspective for designing highly sensitive hydrogen gas sensor from atomic and electronic level.

Fabrication and characterization of a highly sensitive hydrogen gas sensor

A rapidly growing world where sources are decreasing mmoneoney, time causes a big problem for some region. Contaminations get expanding step by step because of the contamination and waste that comes from businesses in light of petroleum derivative. To diminish the utilization of petroleum products around then a characteristic wellspring of energy went about as a deliverer which was not just utilized as a perfect wellspring of energy yet in addition utilized in different fuel and modern cycles. Such gas is hydrogen gas which is the most ideal decision likewise universally acknowledged and present in bounty sum. Yet, hydrogen gas is exceptionally combustible and as its particles are minuscule in size, its scentless, vapid property makes it hard to perceive and recognize effectively in the event that any measure of gas is releasing, such little leakage can bring about a major debacle and its impact stay for a significant stretch. To forestall and recognize such leakage and mishap a sensor should be planned and creation is fundamental. This paper talks about different materials, strategies, and cycles expected to make a viable detecting gadget. Likewise, the entire cycle stream and other plan boundaries are examined with an alternate writing review of paper to make a powerful and valuable sensor for the identification of Hydrogen gas.

Development of Highly Sensitive, Stable and Selective Hydrogen Gas Sensors Based on Sol-Gel Spin-Coated Nb2o5 Thin Films

Development of Highly Sensitive, Stable and Selective Hydrogen Gas Sensors Based on Sol-Gel Spin-Coated Nb2o5 Thin Films

An Analysis of a Highly Sensitive and Selective Hydrogen Gas Sensor Based on a 3D Cu-Doped SnO2 Sensing Material by Efficient Electronic Sensor Interface.

In this research, a highly sensitive and selective hydrogen gas sensor was developed based on Cu-doped SnO2. Sensing characteristics were compared based on SnO2 doped with different concentrations of Cu, and the highest sensitivity and fastest response time were shown when 3% Cu was contained. A 3D structure was formed using a polystyrene to increase the surface-to-volume ratio, which allows more oxygen molecules to bond with the surface of the SnO2 sensing material. Extremely increased sensitivity was observed as compared to the planar structure. A temperature sensor and micro-heater were integrated into the sensor, and the surface temperature was maintained constant regardless of external influences. In addition, an electronic sensor interface was developed for the efficient analysis of real-time data. The developed sensor was wire-bonded to the flexible printed circuit board (FPCB) cable and connected with the sensor interface. Sensitivity and linearity measured based on the developed sensor and interface system were analyzed as 0.286%/ppm and 0.98, respectively, which were almost similar to the results observed by a digital multimeter (DMM). This indicates that our developed sensor system can be a very promising candidate for real-time measurement and can be applied in various fields. The enhanced sensitivity of 3% doped SnO2 toward hydrogen is attributed to the huge number of oxygen vacancies in the doped sample.

Performance Investigation of Novel Pt/Pd-SiO2 Junctionless FinFET as a High Sensitive Hydrogen Gas Sensor for Industrial Applications

In this paper, a junctionless (JL) Silicon FinFET (Fin Field effect transistor) has been designed as a hydrogen gas (H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) sensor. An analytical model has been developed to analyze the response of junctionless FinFET for detection of hydrogen gas. Palladium is used as a catalytic metal gate. The variation in the gas molecule concentration alters the pressure induced on the catalytic metal gate which changes work function of the metal gate. This variation in metal gate work function is used for detecting the presence of the hydrogen gas. Various electrical parameters for which designed gas sensor is analyzed are- surface potential, threshold voltage, drain current, transconductance, output conductance and charge concentration. The sensitivity analysis in terms of threshold voltage and drain current at different pressures is also carried out. The performance of the sensor with catalytic gate metals-palladium (Pd) and platinum (Pt) is analyzed to find which metal gate gives better response as a hydrogen gas sensor. The JL FinFET is also compared with JL Gate All Around (GAA) transistor for threshold voltage and drain current sensitivity.

Highly Fast Response of Pd/Ta2O5/SiC and Pd/Ta2O5/Si Schottky Diode-Based Hydrogen Sensors.

Herein, the fabrication of a novel highly sensitive and fast hydrogen (H2) gas sensor, based on the Ta2O5 Schottky diode, is described. First, Ta2O5 thin films are deposited on silicon carbide (SiC) and silicon (Si) substrates via a radio frequency (RF) sputtering method. Then, Pd and Ni are respectively deposited on the front and back of the device. The deposited Pd serves as a H2 catalyst, while the Ni functions as an Ohmic contact. The devices are then tested under various concentrations of H2 gas at operating temperatures of 300, 500, and 700 °C. The results indicate that the Pd/Ta2O5 Schottky diode on the SiC substrate exhibits larger concentration and temperature sensitivities than those of the device based on the Si substrate. In addition, the optimum operating temperature of the Pd/Ta2O5 Schottky diode for use in H2 sensing is shown to be about 300 °C. At this optimum temperature, the dynamic responses of the sensors towards various concentrations of H2 gas are then examined under a constant bias current of 1 mA. The results indicate a fast rise time of 7.1 s, and a decay of 18 s, for the sensor based on the SiC substrate.

Effect of nanoparticle-embedded 1 dimensional-nanostructures to fabricate highly sensitive and selective hydrogen gas sensors

Owing to the increasing development of in hydrogen economy in modern society, hydrogen gas detection technologies have become important for preventing accidents caused by hydrogen gas buildup, such as explosions and fire outbreaks. Herein, In2O3 nanoparticle (NP)-embedded TiO2 nanofibers (NFs) are synthesized by an electrospinning process, wherein hydrothermally synthesized In2O3 NPs are added to fabricate highly sensitive and selective hydrogen gas detectors. Several TiO2 NF samples corresponding to different amounts of In2O3 NPs were synthesized, and their sensing properties were measured to determine the gas sensor composition with an optimal response to hydrogen. According to the results, the optimum sensor consisted of 0.6 wt% of In2O3 NPs embedded in TiO2 NFs and exhibited a sensing response to 1000 ppm of hydrogen gas 50 times higher than that of a pure TiO2 NF sensor. Furthermore, its hydrogen selectivity was improved, and the responses to several gases measured herein were almost negligible, except for hydrogen gas. Here, the hydrogen sensing properties of In2O3 NP-embedded TiO2 NFs are demonstrated, and their mechanism of operation and optimal constitution determined.

Palladium nanoparticle-decorated multi-layer Ti3C2T x dual-functioning as a highly sensitive hydrogen gas sensor and hydrogen storage.

In this work, palladium nanoparticle (PdNP)-decorated Ti3C2Tx MXene (Pd–Ti3C2Tx) was synthesized by a simple two-step process. For this, multilayer Ti3C2Tx MXene (ML-Ti3C2Tx) was first prepared by a selective HF etching technique, and PdNPs were directly grown on the surface of ML-Ti3C2Tx flakes using a polyol method. The relative weight fraction of PdNPs to ML-Ti3C2Tx was elaborately controlled to derive the optimal size and distribution of PdNPs, thereby to maximize its performance as a hydrogen sensor. The optimized Pd–Ti3C2Tx nanocomposite showed superb hydrogen-sensing capability even at room temperature with sharp, large, reproducible, concentration-dependent, and hydrogen-selective responses. Furthermore, the nanocomposite also unveiled some extent of hydrogen storage capability at room temperature and 77 K, raising a possibility that it can dual-function as a hydrogen sensor and hydrogen storage.

Sputter-Grown Pd-Capped CuO Thin Films for a Highly Sensitive and Selective Hydrogen Gas Sensor

In the present work, hydrogen gas sensing properties of palladium-capped copper oxide (Pd/CuO) thin films have been investigated. The Pd/CuO thin films were deposited on glass substrate for different deposition times (10–30 min) using direct current magnetron sputtering. The Pd/CuO thin films were characterized by x-ray diffraction, field emission scanning electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy for their structural, morphological and compositional properties, respectively. The Pd/CuO thin film sensor deposited for 10 min presents a remarkable sensing performance with fast response/recovery time of 10 s/50 s for hydrogen gas at a concentration of (1000 ppm) and optimum operating temperature of 300°C. The sensor is observed to be highly selective towards hydrogen (H2) gas compared to the other gases such as carbon monoxide (CO) and ammonia (NH3). The sensor is stable under high humidity conditions (60% RH). The studied Pd/CuO thin film sensor can be used to design a simple and low-cost sensor to detect low concentrations of H2 gas for use in hydrogen-driven industries.