Hydrogen Sulfide Gas Sensor Research Articles

Low-concentration H2S gas sensors based on MOF-derived Co3O4 nanomaterials

Metal-organic frameworks (MOF)-based gas sensors have garnered significant interest and are highly desirable for monitoring indoor air quality and mitigating various environmental reclamation challenges. Herein, we describe a unique approach for fabricating hydrogen sulfide (H2S) gas sensors based on MOF-derived cobalt oxide nanosheets (Co3O4 Ns) nanostructures. The surface morphology and porosity of the fabricated material were confirmed through comprehensive Brunauer-Emmett-Teller (BET) and electron microscopy analyses. Chemical composition and phase purity were identified using Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The sensor exhibited remarkable sensitivity towards hydrogen sulfide in the range of 0.5–100 ppm, reaching a maximum response of 1702.61 % at an operating temperature of 250 °C for 100 ppm H2S gas. Furthermore, the sensor demonstrated a detection limit of 500 ppb with a response rate of 78.22 %. A consistent stability over 30 days was observed, validating its suitability for real-world applications. The response and recovery times of the H2S gas sensors were assessed with τres/τrec = 63.56/103.34 s, offering valuable insights into their real-world applicability.

Surface acoustic wave hydrogen sulfide gas sensors based on porous SnO2-SiO2 composite films

A SnO2-SiO2 composite fabricated with an EBE method was developed as the sensitive film for a room-temperature SAW H2S in this work. In this film, the SnO2 nanoparticels, acting as the active adsorption sites, were uniformly deposited on the slanted SiO2 nanorods array with a mesoporous structure. This structure is found to be beneficial for adsorption and diffusion of H2S gas molecules, thus leading to an excellent sensing performance of the sensor. The fabricated sensor exhibited a frequency response ranging from −180 Hz to −13550 Hz toward H2S with a concentration varying from 0.05 ppm to 10 ppm and a fast response, good selectivity and stability. In addition, the sensing mechanism of the sensor was revealed to be lied on the change in film mass during the adsorption process.

Highly Selective and Sensitive Ag-Based Hydrogen Sulfide Gas Sensor Based on Precise Chip Temperature Management

Highly Selective and Sensitive Ag-Based Hydrogen Sulfide Gas Sensor Based on Precise Chip Temperature Management

Design and Simulation of an Ultra-Low-Power Hydrogen Sulfide Gas Sensor with a Cantilever Structure.

Metal oxide gas sensors usually require a few tens of milliwatts of power consumption to operate at high temperature, which limits their application in mobile and portable devices. Here, we proposed a cantilever structure to build an ultra-low power gas sensor for hydrogen sulfide gas detection. By employing a nano-film size effect to reduce the thermal conductivity of the material, and self-heated corrugation configuration, the power consumption of the gas sensor is significantly reduced. Through numerical analysis and finite element simulation, two different gas sensors were designed and the power consumption and stress distribution were analyzed and optimized. Under the operating temperature of 200 °C, only 0.27 mW power is consumed, the stress value is less than 250 MPa and the displacement is a few hundred of nanometers. The results serve as a guide and reference for ultra-low power MEMS device designs.

Achieving One Part Per Billion Hydrogen Sulfide (H2S) Level Detection through Optimizing Composition and Crystallinity of Gold-Decorated Tungsten Trioxide (Au-WO3) Nanofibers.

As a common environmental pollutant and an important breath biomarker for several diseases, it is essential to develop a hydrogen sulfide gas sensor with a low-ppb level detection limit to prevent harmful gas exposure and allow early diagnoses of diseases in low-resource settings. Gold doped/decorated tungsten trioxide (Au-WO3) nanofibers with various compositions and crystallinities were synthesized to optimize H2S-sensing performance. Systematically experimental results demonstrated the ability to detect 1 ppb H2S with a response value (Rair/Rgas) of 2.01 using a 5 at % Au-WO3 nanofibers with average grain sizes of around 15 nm. Additionally, energy barrier difference of sensing materials in air and nitrogen (ΔEb) and power law exponent (n) were determined to be 0.36 eV and 0.7, respectively, at 450 °C indicating that O- is predominately ionic oxygen species and adsorption of O- significantly altered the Schottky barrier between the grain. Such quantitative analysis provides a comprehensive understanding of H2S detection mechanism.

Hydrothermally synthesized MXene Ti3C2/Zn2SnO4 based nanocomposite for H2S sensing at room temperature

Hydrogen sulfide (H2S) gas sensors with high response and minimum limit of detection at room temperature are of great importance to ensure the safety of humans and the environment. A series of samples such as MXene Ti3C2, Ti3AlC2, WS2, MoSe2/Zn2SnO4 and spherical Zn2SnO4 nanoparticles were synthesized via hydrothermal method in this paper. Different characterizations were performed on these samples to check crystal structures, morphologies, chemical states, etc. And gas sensing properties were also performed and analyzed deeply. A series of sensor sheets were fabricated via the spin coating method based on synthesized samples for gas sensing properties. MXene Ti3C2/Zn2SnO4-5 based gas sensor detected the highest response (110) towards 8 ppm H2S with excellent selectivity, the minimum limit of detection (0.01 ppm), mediate long-term stability and good reproducibility compared with other fabricated sensors at room temperature. Also, the sensor response was increased with the increase of H2S concentration. Experimental results showed that the highest response of Ti3C2/Zn2SnO4-5 based gas sensor was accredited to heterojunction, higher BET surface area, and increased oxygen species. The simple way synthesized nanocomposite and fabricated sensors throw a novel idea for tracing H2S at the lowest concentration to prevent different diseases.

Semiconductive (Cu–S)n Metal–Organic Frameworks Hybrid Polyaniline Nanocomposites as Hydrogen Sulfide Gas Sensor

A semiconductive (Cu–S)n metal–organic framework (MOF) incorporated polyaniline (PANI) nanocomposite was applied for hydrogen sulfide (H2S) gas sensing. The (Cu–S)n MOF nanosheets were successfully synthesized using a one-pot reflux method. First, fiber-like (Cu–S)n MOF/ PANI nanocomposites were prepared through an in situ oxidative polymerization. As evaluated by field-emission transmission electron microscopy (FE-TEM), the nanosized spherical (Cu–S)n MOF particles were well-distributed in the fiber matrix. Then, the nanocomposite was spin-coated onto an interdigitated electrode (IDE) for H2S gas sensing, displaying high sensitivity, selectivity, repeatability, and stability similar to pure PANI. As a result, 3wt% (Cu–S)n MOF/ PANI nanocomposite showed the best performance for H2S detection. The mechanism for improving H2S sensing performance might be attributed to the conductive composite networks' significantly enhanced conductivity and increased doping sites of the (Cu–S)n MOF. In addition, the energy band gaps of PANI-based nanocomposites were optimized by the incorporated (Cu–S)n MOF, indicating the successful hybridization of energy levels between inorganic MOF and organic PANI. This study first demonstrates semiconductive MOF-PANI-based nanocomposites for H2S gas sensing.

Enhance hydrogen sulfide (H2S) gas sensor based on metal oxide semiconductor (NiO) thin films

Enhance hydrogen sulfide (H2S) gas sensor based on metal oxide semiconductor (NiO) thin films

A general and facile approach to flower-like ZnO fabrication

ZnO nanosheets with nanograin distributions, high mesoporosity, and ultrathin thickness have garnered considerable attention owing to their intriguing properties, such as high surface-to-volume ratio and chemical reactivity. Although various methods for fabricating two-dimensional structures have been reported, the surfactant-assisted method is advantageous as it produces nanosheet structures at the water–air interface without affecting the crystal structure of the material. This study developed an innovative surfactant-assisted synthesis method to fabricate flower-like Zinc Oxide (f-ZnO) nanostructures. The synthesis, performed at a mild temperature of 70 °C, yields f-ZnO with high surface area-to-volume ratios and porous morphology. The f-ZnO demonstrates photoelectrochemical (PEC) performance due to increased interfacial contact with electrolytes and the formation of a wurtzite ZnO crystal structure. Additionally, f-ZnO exhibits sensitivity and selectivity as a hydrogen sulfide (H2S) gas sensor. This facile synthesis method opens new avenues for developing functional oxide nanostructures for sensors, catalysts, and energy storage systems.

Fast-response hydrogen sulfide gas sensor based on electrospinning Co3O4 nanofibers-modified CuO nanoflowers: Experimental and DFT calculation

In this paper, copper oxide nanoflower/cobalt tetroxide nanofiber (CuO/Co3O4) composites are synthesized by hydrothermal method and electrospinning technology, and a high-performance gas sensor for H2S is successfully prepared. The morphology, microstructure and elemental composition of the materials are characterized by XRD, SEM, TEM and XPS. The CuO/Co3O4 sensor has the best response to H2S when the mass percentage of Co3O4 is 25 wt%, and the response is the highest at the operating temperature of 200 °C. By comparison, CuO/Co3O4 sensor has higher response (194 %@25 ppm) and faster response/recovery time (6 s/25 s@25 ppm) at the optimum temperature. It also has excellent repeatability, long-term stability and selectivity. According to the analysis, the improvement of H2S gas sensing properties of CuO/Co3O4 sensor is mainly due to the larger specific surface area brings more active sites, which promotes the adsorption of gas on the material surface. At the same time, the p-p heterojunction at the contact interface of CuO/Co3O4 nanocomposites also plays a very important role. In addition, theoretical calculation based on the first principle further reveals the improvement of H2S gas sensing performance of CuO/Co3O4 nanocomposites.

Solution-Processed, Highly-Efficient Organic Field-Effect Transistor Based Hydrogen Sulfide Gas Sensor at Sub-ppm Regime

Solution-Processed, Highly-Efficient Organic Field-Effect Transistor Based Hydrogen Sulfide Gas Sensor at Sub-ppm Regime

Investigation of the Morphological, Optical, and D.C Electrical Characteristics of Synthesized (Bi2O3/ZnO) Nanocomposites, as Well as Their Potential Use in Hydrogen Sulfide Gas Sensor

Investigation of the Morphological, Optical, and D.C Electrical Characteristics of Synthesized (Bi2O3/ZnO) Nanocomposites, as Well as Their Potential Use in Hydrogen Sulfide Gas Sensor

Cobalt ions induced morphology control of metal-organic framework-derived indium oxide nanostructures for high performance hydrogen sulfide gas sensors

Real-time gas sensors with high response and selectivity are highly desirable for hydrogen sulfide (H2S) monitoring concentration changes in the environment, especially at the ultra-trace level. Herein, cobalt-doped indium oxide (In2O3) with shorter-length nanorings was synthesized by foreign metal cobalt ions. By controlling the morphology of the material and calcinating the indium-based metal-organic frameworks (In-MOFs), the nanostructures of the obtained materials have a larger specific surface area, which further improves the sensing performance. The sensor prepared with a suitable amount of cobalt doping materials can exhibit the best gas-sensing performance. The Co-doped In2O3 sensor shows a high response to 2 ppm H2S (∼12.6) at 225 °C, low detection limits (100 ppb), and excellent selectivity, which is 5.34 times higher than pure In2O3 at 300 °C. Moreover, the potential growth mechanism speculates that the presence of Cobalt ions leads to a change in material morphology from nanorods to nanorings. This work provides an implementable method for controlling the morphology of the materials, which could facilitate the development of high-performance gas sensors.

Copper-multiwalled carbon nanotubes decorated fiber-optic surface plasmon resonance sensor for detection of trace hydrogen sulfide gas

A fiber-optic surface plasmon resonance (SPR) hydrogen sulfide (H2S) gas sensor is proposed and fabricated by using silver/triaminopropyltriethoxysilane/copper-multiwalled carbon nanotubes (Ag/APTES/Cu-MWCNT) as sensing film. A single-mode fiber (SMF) is spliced between two multimode fibers (MMF) to form an MMF-SMF-MMF sensing structure. The Ag/APTES/Cu-MWCNT sensing film is coated on the surface of SMF. The performance and stability of the sensor were investigated in detail. With the increase of H2S concentration in the range of 10–100 ppm, the redshift of the resonance dip reaches 126.465 nm, and the logarithm of H2S concentration and the resonance dip wavelength shift satisfy the linear relationship. In the range of 1–10 ppm, the wavelength shifts 117.421 nm, and H2S concentration and the dip wavelength shift meet a linear relationship. The sensitivity (12.9849 nm/ppm) is obtained, the detection limit (0.146 ± 0.031 ppm) is determined, and the response time is about 28 s. The sensor has excellent selectivity, good time, humidity and temperature stability, which has potential application in the field of trace H2S gas monitoring.

Unpolymerized and polymerized discotic liquid crystal-based materials for hydrogen sulfide gas-sensing applications

Hexa-peri-hexabenzocoronenene (HBC)-derived discotic liquid crystal (DLC)-based material carrying polymerizable diacetylene (DA) side chains, named HBC-1,2,4-Ph-DA-C12, was used to create a thin film as hydrogen sulfide (H2S) gas sensor. Both unpolymerized and polymerized DLC’s thin films show high performance for gas sensing. However, polymerized DLC-based thin film through ultraviolet (UV) irradiation demonstrated excellent mechanical properties and high environmental tolerance although slightly poorer gas sensing that the unpolymerized film. Resistivity measurement and UV–visible absorption spectra revealed that the DLC film functions as a gas sensor by exploiting the protic acid doping mechanism of H2S. At 60% and 80% relative humidity (RH) under N2 and air atmospheres, respectively, the sensors showed good repeatability, maintaining 50% accuracy under N2 after 30 days. These thin films exhibit a linear response to H2S concentrations of 1–10 ppm (maximal R2 = 0.9947) and a lower limit of detection of 1 ppm. Our results suggest that such DLC-based gas sensors are excellent at detecting H2S gas.

Parts-per-billion-level detection of hydrogen sulfide based on doubly resonant photoacoustic spectroscopy with line-locking

We report on the development of a highly sensitive hydrogen sulfide (H2S) gas sensor exploiting the doubly resonant photoacoustic spectroscopy technique and using a near-infrared laser emitting at 1578.128 nm. By targeting the R(4) transition of H2S, we achieved a minimum detection limit of 10 part per billion in concentration and a normalized noise equivalent absorption coefficient of 8.9 × 10−12 W cm−1 Hz−1/2. A laser-cavity-molecule locking strategy is proposed to enhance the sensor stability for fast measurement when dealing with external disturbances. A comparison among the state-of-the-art H2S sensors using various spectroscopic techniques confirmed the record sensitivity achieved in this work.

Synthesis, characterizations, and hydrogen sulfide gas sensing application of BiOx (x = 1, 1.5) nanostructures

Hydrogen sulfide is one of the harmful gases that contribute to air pollution. Therefore, there is a need to develop high-response hydrogen sulfide (H₂S) gas sensors. Herein, the bismuth oxide nanostructured material was prepared using the hydrothermal chemical route. The prepared material was characterized using XRD, FESEM, TEM, XPS, EDS, and UV–visible spectroscopy techniques. The gas sensor device was fabricated using bismuth oxide nanomaterial, and gas sensing properties were investigated. The sensor exhibited the highest response of 22–92% towards H₂S gas at 250 °C for 10–100 ppm concentration range, respectively. The 92% response was recorded for 100 ppm H2S gas with rapid response and recovery times of 511 and 492 s, respectively. The sensor was tested at different operating temperatures and H2S gas concentrations. The sensor's selectivity, dynamic resistance response repeatability, and long-term (30 days) stability were studied. The nanostructured bismuth oxide can be a promising candidate for high-response H₂S sensor applications.

Design and Characteristics of various types of gas sensors for hydrogen sulfide gas detection - A Review

This paper reviews the sensor design and the gas sensing characteristics such as stability, sensitivity, response time, range of operation etc. to detect and monitor highly toxic gas such as hydrogen sulfide. This gas is responsible for many deaths in the industrial environments and flaura and fauna of a region. The comparison between the gas sensors can be done on the basis of operating range of gas concentration and working principle. Also the various limitations of each gas sensor has been discussed. From this study the best possible materials that give best possible characteristics for the hydrogen sulfide gas sensor fabrication have been identified. Using this knowledge, a highly sensitive and selective gas sensor that will have industrial uses too will be fabricated.

Development of a Ferrite Film Based Solid State Sensor System for Ultra Low Concentration Hydrogen Sulfide Gas Detection

We report on a selective hydrogen sulfide gas sensor based on zinc ferrite film which is obtained by a microwave-assisted solvothermal deposition route. The response of the chemiresistive device is found to be in the range of 1872% - 90% for 5.6 ppm – 0.3 ppm of H₂S gas at an operating temperature of 250°C. The density functional theory studies suggest physisorption of the H₂S molecules at the partially-inverted ZnFe₂O₄ surface as the reason behind the fast rise (of the order of ~40 sec) and fall time (of the order of ~70 sec) with complete recovery of the device. Finally, a dual-differential subtractor based auto-balancing interface circuit is proposed to drive this sensor which is advantageous in terms of accuracy and particularly suitable for a device such as ours, which has a wide dynamic range.

Large‐Area Synthesis of Ultrathin, Flexible, and Transparent Conductive Metal–Organic Framework Thin Films via a Microfluidic‐Based Solution Shearing Process (Adv. Mater. 12/2022)

Gas Sensors In article number 2107696, Il-Doo Kim, Steve Park, and co-workers introduce a microfluidic-based solution shearing combined with post-synthetic rapid crystallization (MASS-PRC) process, which enables the formation of high-quality conductive, flexible and transparent Ni3(HITP)2 films with thickness controllability down to 10 nm in a rapid large-area scalable manner. They fabricate hydrogen sulfide (H2S) gas sensors using the film, which can detect the target gas under humid conditions, and exhibit the highest sensing performance to date.