H2S Sensor Research Articles

Ultra-thin ALD CoOx-ZnO heterogenous films as highly sensitive and environmentally friendly H2S sensor

Ultra-thin ALD CoOx-ZnO heterogenous films as highly sensitive and environmentally friendly H2S sensor

A comparative DFT study of H2S adsorption and sensor properties of pristine, mono- and bimetallic cobalt doped arsenene

The adsorption and sensor performance of atmospheric hazardous gas H2S on pristine, Co and Co2-doped arsenene monolayers were investigated by density function theory. By comparative analyzing the parameters of density of state, adsorption energy, charge transfer, energy band structure, recovery time and sensitivity of three systems, the excellent degree of the adsorption performance for H2S was revealed. The findings show that the pristine arsenene monolayer exhibits poor sensor properties for H2S gas. After the doping of Co metal atoms, the adsorption properties of arsenene are significantly improved. Therefore, the study reveals that Co monoatomic doped arsenene can be used as a sensor and Co2 diatomic doped arsenene can be used as an adsorbent for H2S. The study indicates that the doping of Co can produce better sensing performance than pristine arsenene, which provides valuable guidance for research on arsenene as gas sensor or adsorbent.

Ultraviolet-Induced Gas Sensing Performance of Ag/WO3/rGO Nanocomposites for H2S Gas Sensors

The attention toward cost-effective and high-performance H2S sensors is increasing due to the growing need for physical health and environmental monitoring. In this paper, Ag/WO3/reduced graphene oxide (rGO) nanocomposites were synthesized by using a microwave-assisted gas–liquid interfacial method. Nanomaterials with different Ag doping contents were successfully prepared with AgNO3 as an additive. The Ag/WO3/rGO sensors exhibit remarkable selectivity toward H2S, and the gas sensing performances of Ag-doped WO3/rGO gas sensors are significantly better than those of WO3/rGO. At 150 °C, the response value of the 10 wt % Ag/WO3/rGO gas sensor to 100 ppm H2S is 204.5, which is 7 times higher than that of WO3/rGO, and the response/recovery time of the sensor is 9/49 s, respectively. Additionally, the gas sensing performance of the sensor is further enhanced under ultraviolet (UV) irradiation. The response value is enhanced to 685.8, which is 3 times higher than that without UV irradiation, and the response/recovery time is reduced to 8/38 s, respectively. The sensing mechanism is also discussed. This work offers a potential application for H2S detection in environmental monitoring and smart healthcare.

Plasmonic grating H2S sensor based on a chitosan-polyaniline-nano-composite

In this study, a plasmonic sensor was designed based on the grating coupling to detect the low concentration of H2S as a toxic chemical. The polyaniline nanostructure was prepared using the laser ablation technique in a chitosan solution and the final products were tested using analytical methods. The chitosan-polyaniline nanocomposite layer was used as a sensing layer and coated on the surface of 1D polydimethylsiloxane grating. The variation of reflectivity with different concentrations of H2S was registered from the surface of the grating for evaluating the sensor’s response. Finally, it was explained using the Langmuir isotherm absorption model. The limit of detection and the sensitivity of chitosan-polyaniline-nanocomposite were about 1 ppm and 0.10767 for the detection of H2S, respectively.

Cu-doped SnO2/rGO nanocomposites for ultrasensitive H2S detection at low temperature

Hydrogen sulfide (H2S) detection remains a significant concern and the sensitivity, selectivity, and detection limit must be balanced at low temperatures. Herein, we utilized a facile solvothermal method to prepare Cu-doped SnO2/rGO nanocomposites that have emerged as promising candidate materials for H2S sensors. Characterization of the Cu-SnO2/rGO was carried out to determine its surface morphology, chemical composition, and crystal defects. The optimal sensor response for 10 ppm H2S was ~1415.7 at 120 °C, which was over 320 times higher than that seen for pristine SnO2 CQDs (Ra/Rg = 4.4) at 280 °C. Moreover, the sensor material exhibited excellent selectivity, a superior linear working range (R2 = 0.991, 1–150 ppm), a fast response time (31 s to 2 ppm), and ppb-level H2S detection (Ra/Rg = 1.26 to 50 ppb) at 120 °C. In addition, the sensor maintained a high performance even at extremely high humidity (90%) and showed outstanding long-term stability. These superb H2S sensing properties were attributed to catalytic sensitization by the Cu dopant and a synergistic effect of the Cu-SnO2 and rGO, which offered abundant active sites for O2 and H2S absorption and accelerated the transfer of electrons/holes.

Heterostructure construction of SnS2 Debye nanowires modified with ZnO nanorods for chemiresistive H2S detection in sulfur hexafluoride decomposition products

The fast detection of low concentration of H2S sensor has certain engineering significance for SF6 electrical equipment. Here, a sensitive material based on ZnO nanorods-modified SnS2 Debye nanowires was prepared for the purpose of detecting H2S in the SF6 background. At the optimum operating temperature (180 °C), the sensor response and recovery times to 30 ppm H2S were 10 s and 51 s, respectively. The response value of the sensor was 71.2%. The sensor has a lower detection limit of 50 ppb for H2S and exhibits excellent stability, moisture resistance, and long-term stability. The sensor has specific selection for H2S in SF6 decomposition products. In addition, it is proved by first principles calculation that ZnO enhances the adsorption performance of SnS2 on H2S. The H2S sensor prepared by ZnO-SnS2 is expected to be a candidate for detecting hazardous gases in the environment and detecting SF6 decomposition products.

Highly selective H2S sensor realized via the facile synthesis of N-doped ZnO nanocrystalline films

Highly selective H2S sensor realized via the facile synthesis of N-doped ZnO nanocrystalline films

Reperfusion-induced injury and the effects of the dithioacetate type hydrogen sulfide donor ibuprofen derivative, BM-88, in isolated rat hearts

Hydrogen sulfide (H2S) plays an important role in cardiac protection by regulating various redox signalings associated with myocardial ischemia/reperfusion (I/R) induced injury. The goal of the present investigations is the synthesis of a newly designed H2S-releasing ibuprofen derivative, BM-88, and its pharmacological characterization regarding the cardioprotective effects in isolated rat hearts. Cytotoxicity of BM-88 was also estimated in H9c2 cells. H2S-release was measured by an H2S sensor from the coronary perfusate. Increasing concentrations of BM-88 (1.0 to 20.0 µM) were tested in vitro studies. Preadministration of 10 µM BM-88 significantly reduced the incidence of reperfusion-induced ventricular fibrillation (VF) from its drug-free control value of 92% to 12%. However, no clear dose dependent reduction in the incidence of reperfusion-induced VF was observed while different concentrations of BM-88 were used. It was also found that 10 µM BM-88 provided a substantial protection and significantly reduced the infarct size in the ischemic/reperfused myocardium. However, this cardiac protection was not reflected in any significant changes in coronary flow and heart rates. The results support the fact that H2S release plays an important role mitigating reperfusion-induced cardiac damage.

Batch fabrication of H2S sensors based on evaporated Pd/WO3 film with ppb-level detection limit

H2S is an extremely toxic gas that can cause damage to the respiratory and nervous systems or even death, therefore it is of great significance to develop high performance H2S sensors. However, traditional techniques including brush painting and drop casting methods adversely affect the batch response consistency of the sensors owing to the uncontrollable film formation process, impeding the mass industrial manufacture of gas sensors. In this work, WO3 and Pd are sequentially deposited onto alumina substrates by e-beam evaporation. The results show that the Pd/WO3 sensor exhibits high sensitivity (2.68 ppm−1), short response time (14 s toward 0.7 ppm), and low detection limit (50 ppb) toward H2S at an optimal operating temperature of 250 °C. Moreover, owing to the uniform distribution of Pd/WO3 film, the prepared H2S sensors present a good batch response uniformity with a low relative standard deviation of response values of less than 4.80%. This work provides an effective method for batch-preparing high performance H2S sensors with ppb-level detection limits, which is expected to realize a reliable and massive fabrication method for gas sensors.

Composition of the Gas-Air Mixture in the Containment and Suppression of Forest Fires with Promising Extinguishing Agents

This paper presents experimental research findings on the gas composition of pyrolysis and combustion products of typical forest fuels (leaves, needles, twigs, a mixture of these, and timber). These experiments were performed for the combustion and application of a fire extinguishing agent to a pyrolyzing material. Water, a bischofite solution, a bentonite slurry, and a foaming agent solution were utilized. Two gas analysis systems were used, as follows: an industrial one based on CO2, CO, H2, CH4, and O2 sensors and a scientific one (a gas analyzer with H2, CH4, H2S, SO2, CO, and CO2 sensors). Fires were extinguished by using two common techniques, as follows: continuous liquid supply and cycling spraying. The comparative efficiency of applying a group of fire extinguishing agents to forest fires was estimated, taking account of liquid consumption, suppression time, and environmental pollution. A method was proposed for calculating the relative efficiency factors of fire extinguishing agents when containing and suppressing forest fires, allowing for the consumed time, resources, and anthropogenic emissions.

Feasible H2S Sensing in Water with a Printed Amperometric Microsensor.

Concern over pollution has led to an increase in wastewater treatment systems, which require constant monitorization. In particular, hydrogen sulfide (H2S) is a toxic gas, soluble in water, commonly found in industrial and urban effluents. For proper removal control, fast, durable, and easy-to-handle analytical systems, capable of on-line measurements, such as electrochemical sensors, are required. Moreover, for a proper monitoring of said treatment processes, analysis must be carried out through all steps, thus needing for an economic and highly reproducible method of sensor fabrication. Digital printing have risen in the last few years as technologies capable of mass producing miniaturized electronical devices, allowing for the fabrication of amperometric sensors. Here, a 2 mm2 graphite (Gr) electrode, modified with different dispersions of single-walled carbon nanotubes (SWCNTs), poly(vinyl alcohol), poly(diallyl dimethylammonium chloride), and polylactic acid (PLA), is presented as a H2S sensor. SWCNTs allow for lower oxidation potentials, higher sensitivity, and a reduced rate of sulfur poisoning, while polymer dispersion of PLA increases mechanical stability and as a result, electrochemical performance. This microsensor presents an optimal pH working range between 7.5 and 11.0, a limit of detection of 4.3 μM, and the capacity to operate on complex matrices for H2S contamination detection.

Ppb-level all-optical off-axis QEPAS gas sensor based on dual-wavelength demodulation of out-of-plane vibration mode

In Quartz Enhanced Photoacoustic Spectroscopy (QEPAS), due to the strained material and piezoelectric effect of the Quartz Tuning Fork (QTF), the in-plane mode of QTF is generally detected, requiring micron-scale precise and stable optical alignment and convergence. It poses a significant challenge for the use of light sources and has become a bottleneck for practical implementations of QEPAS. In this paper, a ppb-level all-optical off-axis QEPAS gas sensor based on dual-wavelength demodulation of out-of-plane mode is proposed and experimentally demonstrated. A dual-wavelength Fabry-Perot (FP) Interferometer with Ellipse Fitting-Differential Cross Multiply (EF-DCM) algorithm is designed and employed to demodulate the out-of-plane mode of off-axis QTF, which is approximately 80 times stronger than the conventional in-plane mode. This work established a novel ultra-sensitive off-axis QEPAS-based hydrogen sulfide (H2S) sensor with a 1.5 W fiber-amplified near-infrared diode laser. The minimum detection limit and normalized noise equivalent absorption of the developed H2S sensor is 74.19 ppb with 1 s integration time and 2.68 × 10−9 W∙cm−1∙Hz−1/2 respectively, beyond previously reported QEPAS-based H2S sensors. This technique effectively utilizes the out-of-plane mode of QTF and realizes the simultaneous enhancement of off-axis location and out-of-plane vibration mode detection in QEPAS, allowing a novel approach for the development of ultra-sensitive QEPAS gas sensors with notable practical application prospects.

Monitoring of COS, SO2, H2S, and CS2 gases by Al24P24 nanoclusters: a DFT inspection

Through utilizing density functional theory (DFT), the current work investigates the potential uses of Al24P24 fullerene for detecting CS2, H2S, SO2, and COS. The interaction order for the stability of these gases was SO2 > H2S > COS > CS2. The moment of electric dipole and molecules' adsorption energy seems correlated. Al24P24 fullerene is regarded as an electronic sensor of the Ф-type for detecting SO2 and CS2. According to the findings, CS2 and SO2 might act as Al24P24 fullerenes when H2S is present. Nevertheless, we cannot presume it to be a COS and H2S sensor of Ф-type. At room temperature, the fullerene of Al24P24 has a quick recovery time of 0.50μs and 0.17s in CS2 and SO2 desorption from the surface. It can thus be inferred that it has the ability to function in moist media.

Ag2SO4-Ag2S transformation in SnO2-based nanofibers for high selectivity and response H2S sensors

Tin-based gas sensors have been developed for many years owing to their advantages of low price, high response and stability. However, selectivity remains a significant issue. Herein, Ag-SnO2 nanofibers are synthesized using AgCl as the doping reagent. The 3%Ag-SnO2 nanofibers sensors show a high response of 68 toward 1 ppm H2S at 90 °C. Besides, the sensor with 3% AgCl possesses the shortest response time about 136 s at 150 °C which is only 30% value of the sensor without AgCl doping. It is also demonstrated that the nanofibers show a high selectivity towards H2S. According to the ex situ x-ray photoelectron spectrum and x-ray diffraction results, AgCl was transferred to Ag2S after Ag-SnO2 was exposed to H2S, and reversible transformation between Ag2SO4 and Ag2S was the main mechanism for H2S detection. Compared with pure SnO2 nanofiber sensors, the presence of Ag2S with high conductivity greatly affects the resistance to H2S, resulting in high selectivity and response. This mechanism differs from that of the transformation between Ag2O and Ag2SO4. This study may provide a new strategy for the design and investigation of sensors with high selectivity.

Regulating the electronic status on open WO2.83 surfaces for ultrasensitive H2S sensors

Engineering open nanostructures with regulable surface electron status possess great potential to increase gas-sensing performance of metal oxide semiconductor. Here, we develop a mesoporous tungsten oxide with special non-stoichiometric nature and double-activated surface electron status to realize ultralow-concentration detection of hydrogen sulfide. We found that the ordered mesoporous framework plays a crucial role in inducing the kinetic evolution to selectively form fixed non-stoichiometric meso-WO2.83 crystal, while the bulk-WO3 trends to lead the formation of bulk-WO2.9 or bulk-WO2.72 crystal. Impressively, the meso-WO2.83 crystal and co-existing oxygen defects exhibit obviously enhanced surface electron resonance and delocalization, thus leading a marked localized surface plasmon resonance (LSPR) effect. Further theoretical and experimental results confirm that the LSPR effect and oxygen defects endow special surface electron status to markedly improve the adsorption and electron transfer process of H2S molecules. The as-obtained meso-WO2.83 based MEMS sensors exhibit superior sensitivity, rapid response (<7 s), and ultralow detection limit of 5 ppb H2S. Our proposed strategy of open nanostructures with regulable surface electron status may create a new path to design fast and highly-effective H2S detection.

Pd/Pt-Bimetallic-Nanoparticle-Doped In2O3 Hollow Microspheres for Rapid and Sensitive H2S Sensing at Low Temperature

H2S is a poisonous gas that is widespread in nature and human activities. Its rapid and sensitive detection is essential to prevent it from damaging health. Herein, we report Pd- and Pt-bimetallic-nanoparticle-doped In2O3 hollow microspheres that are synthesized using solvothermal and in situ reduction methods for H2S detection. The structure of as-synthesized 1 at% Pd/Pt-In2O3 comprises porous hollow microspheres assembled from In2O3 nanosheets with Pd and Pt bimetallic nanoparticles loaded on its surface. The response of 1 at% Pd/Pt-In2O3 to 5 ppm H2S is 140 (70 times that of pure In2O3), and the response time is 3 s at a low temperature of 50 °C. In addition, it can detect trace H2S (as low as 50 ppb) and has superior selectivity and an excellent anti-interference ability. These outstanding gas-sensing performances of 1 at% Pd/Pt-In2O3 are attributed to the chemical sensitization of Pt, the electronic sensitization of Pd, and the synergistic effect between them. This work supplements the research of In2O3-based H2S sensors and proves that Pd- and Pt-bimetallic-doped In2O3 can be applied in the detection of H2S.

Tailoring Of Poly(N-Methyl Pyrrole) Thin Film Surface With Au-Nanoparticles For Selective Sensing Of H2S

We have demonstrated a highly selective H2S sensor fabricated out of Au-nanoparticles decorated Poly (N-Methyl Pyrrole) thin film. Electrochemical process parameters were initially optimized for uniform deposition of Poly (N-Methyl Pyrrole) on planar platinum substrate. Single step chronopotentiometric deposition resulted in a uniform and adhesive polymeric matrix which served as the basic sensing platform. To inculcate selectivity to the synthesized sensor backbone, the polymeric surface was tailored with Au nanoparticles via cyclic voltammetry. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX) and FTIR spectroscopy were carried out to investigate morphological and structural aspects of the sensory material. The semiconductive regime of operation of the sensor was revealed by V-I characterization. Comparative investigations clearly indicated inclusion of Au nanoparticles resulted in better sensing behaviour than pristine polymeric matrix. Most interesting results were obtained on validating the sensor under independent atmospheres of NH3, NO2, SO2, and H2S where the sensor reflected fingerprinting of H2S. Successful detection of H2S with commendable response and recovery behaviour was possible down to concentration of 5 ppm. The overall sensing behaviour of the nanoparticles tailored polymeric matrix could open up opportunities for complex sensing platforms like e-noses.

H2S Sensors: Synthesis, Optical Properties, and Selected Biomedical Applications under Visible and NIR Light.

Hydrogen sulfide (H2S) is an essential signaling gas within the cell, and its endogenous levels are correlated with various health diseases such as Alzheimer's disease, diabetes, Down's syndrome, and cardiovascular disease. Because it plays such diverse biological functions, being able to detect H2S quickly and accurately in vivo is an area of heightened scientific interest. Using probes that fluoresce in the near-infrared (NIR) region is an effective and convenient method of detecting H2S. This approach allows for compounds of high sensitivity and selectivity to be developed while minimizing cytotoxicity. Herein, we report a review on the synthesis, mechanisms, optical properties, and selected biomedical applications of H2S sensors.

Valorization of Agricultural Waste as a Chemiresistor H2S-Gas Sensor: A Composite of Biodegradable-Electroactive Polyurethane-Urea and Activated-Carbon Composite Derived from Coconut-Shell Waste.

In this study, a high-performance H2S sensor that operates at RT was successfully fabricated using biodegradable electroactive polymer-polyurethane-urea (PUU) and PUU-activated-carbon (AC) composites as sensitive material. The PUU was synthesized through the copolymerization of biodegradable polycaprolactone diol and an electroactive amine-capped aniline trimer. AC, with a large surface area of 1620 m2/g and a pore diameter of 2 nm, was derived from coconut-shell waste. The composites, labeled PUU-AC1 and PUU-AC3, were prepared using a physical mixing method. The H2S-gas-sensing performance of PUU-AC0, PUU-AC1, and PUU-AC3 was evaluated. It was found that the PUU sensor demonstrated good H2S-sensing performance, with a sensitivity of 0.1269 ppm-1 H2S. The H2S-gas-sensing results indicated that the PUU-AC composites showed a higher response, compared with PUU-AC0. The enhanced H2S-response of the PUU-AC composites was speculated to be due to the high surface-area and abounding reaction-sites, which accelerated gas diffusion and adsorption and electron transfer. When detecting trace levels of H2S gas at 20 ppm, the sensitivity of the sensors based on PUU-AC1 and PUU-AC3 increased significantly. An observed 1.66 and 2.42 times' enhancement, respectively, in the sensors' sensitivity was evident, compared with PUU-AC0 alone. Moreover, the as-prepared sensors exhibited significantly high selectivity toward H2S, with minimal to almost negligible responses toward other gases, such as SO2, NO2, NH3, CO, and CO2.

Highly Selective H2S Gas Sensor Based on Ti3C2Tx MXene-Organic Composites.

Cost-effective and high-performance H2S sensors are required for human health and environmental monitoring. 2D transition-metal carbides and nitrides (MXenes) are appealing candidates for gas sensing due to good conductivity and abundant surface functional groups but have been studied primarily for detecting NH3 and VOCs, with generally positive responses that are not highly selective to the target gases. Here, we report on a negative response of pristine Ti3C2Tx thin films for H2S gas sensing (in contrast to the other tested gases) and further optimization of the sensor performance using a composite of Ti3C2Tx flakes and conjugated polymers (poly[3,6-diamino-10-methylacridinium chloride-co-3,6-diaminoacridine-squaraine], PDS-Cl) with polar charged nitrogen. The composite, preserving the high selectivity of pristine Ti3C2Tx, exhibits an H2S sensing response of 2% at 5 ppm (a thirtyfold sensing enhancement) and a low limit of detection of 500 ppb. In addition, our density functional theory calculations indicate that the mixture of MXene surface functional groups needs to be taken into account to describe the sensing mechanism and the selectivity of the sensor in agreement with the experimental results. Thus, this report extends the application range of MXene-based composites to H2S sensors and deepens the understanding of their gas sensing mechanisms.