A sensitive H2S sensor using MoS2/WO3 composite

Singh, Sukhwinder; Dogra, Nitesh; Sharma, Sandeep

doi:10.1016/j.matpr.2019.12.104

Cited by 14 publications

(10 citation statements)

References 5 publications

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“…In another case, Zhang et al have reported better ammonia and formaldehyde gas sensing via a metal oxide-graphene composite . In our previous report, we have also shown H 2 S detection using a MoS 2 /WO 3 composite, but at 350 °C . Here, a MoS 2 /WO 3 composite was obtained via a two-step synthesis approach.…”

Section: Introductionmentioning

confidence: 82%

“…In addition a doping based strategy has also been found to improve the sensing and selectivity properties of the MoS 2 or other host materials . Consequently, significant efforts have been devoted to combine materials with entirely different physical properties, so that enhanced gas-sensing performance with better response-recovery features can be obtained. − …”

Section: Introductionmentioning

confidence: 99%

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MoS₂/WO₃Nanosheets for Detection of Ammonia

Singh

Deb

Sarkar

et al. 2021

ACS Appl. Nano Mater.

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100

107

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This article demonstrates the use of a p-MoS2/n-WO3 heterojunctions based ultra sensitive and selective chemiresistive ammonia sensor that operates at 200◦ C. Surprisingly, the composite based sensor exhibited significant enhancement in ammonia sensing as compared to MoS2 (p-type) and WO3 (n-type) counterparts. The device also displayed excellent response-recovery features over a wider range of ammonia concentration together with superior selective nature toward ammonia as compared acetone, ethanol, methanol, isopropanol, formaldehyde, benzene, and hydrogen sulfide. Empowered by better signal-to-noise ratio, ammonia detection down to 1 ppm has become possible and can be further improved with the use of serpentine type electrodes. The device has shown a relative response of 207% for 200 ppm of ammonia with response and recovery times of 80 and 70 s, respectively. Moreover, these experimental results were further supplemented by density functional theory (DFT) simulation that were used to understand the adsorption kinetics and the sensing mechanism. A significant amount of charge transfer (0.082 e) between the adsorbed ammonia molecule and the MoS2/WO3 surface has been predicted by Bader analysis. Analysis also revealed a large negative adsorption energy ≈3.86 eV (373 kJ/mol) per ammonia molecule, implying the adsorption process to be chemisorption in nature. The band structure analysis further confirmed that ammonia adsorption on MoS2/WO3 is accompanied by an increase in band gap (by ≈ 96 meV). The present work illustrates the potential use of composite based heterostructures for monitoring ammonia gas in real fields.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

MoS₂/WO₃Nanosheets for Detection of Ammonia

Singh

Deb

Sarkar

et al. 2021

ACS Appl. Nano Mater.

Self Cite

100

107

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“…Most of the sensors display a significant decrease in the response under such highly humid conditions. ,, Hence, there exist enough opportunities for improving the material properties to address these limitations of sensor devices. Different strategies such as doping, grain size reduction, and hybridization have been adopted to address some of these challenges. − Among these, the hybridization or composite-based approach has proven to be useful as it offers improved performance and selectivity while maintaining the unique properties of the individual material. − For instance, improved performance in ammonia sensing was shown in the case of MoS 2 /CuO n–p heterojunctions, MoS 2 /Co 3 O 4 hybrid, MoS 2 /multiwalled carbon nanotubes, polyaniline/SrGe 4 O 9 nanocomposite, TiO 2 -supported Ti 3 C 2 T x nanosheets, and ref and MoS 2 /WO 3 composites . A ternary composite-based approach has also been reported to enhance the ammonia sensing properties of MoS 2 …”

Section: Introductionmentioning

confidence: 99%

MoS₂/MoO₃ Nanocomposite for Selective NH₃ Detection in a Humid Environment

Singh

Deb

Sarkar

et al. 2021

ACS Sustainable Chem. Eng.

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110

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Designing a material with novel sensing properties under extreme working conditions has remained a challenging task. Here, we report a facile two-step approach to develop a MoS 2 /MoO 3 composite with enhanced surface properties. When used as a gas sensor at 25 °C, it displayed superior sensing properties, selectivity, and a stable response toward ammonia against various reducing and oxidizing gases under highly humid conditions (relative humidity ≈ 95%). The composite exhibited a relative response of ≈55% (15% for 1 ppm) toward 50 ppm of NH 3 with smaller response τ res. and recovery τ rev. times of 45 and 53 s, respectively. It also displayed complete recovery without any external optical or thermal stimulus. The enhanced sensing properties of the composite are attributed to the synergistic effect arising from heterostructure formation between two base materials. The sensor displayed a decrease in resistance when exposed to NH 3 , a reducing gas, thus indicating its n-type character, which was further confirmed by performing Mott−Schottky (MS) measurements on MoS 2 and the MoS 2 /MoO 3 composite, both displaying n-type behavior with increased electron densities of the composite. Further, to understand the adsorption process and the resulting sensing properties, density functional theory simulations were performed using a pristine and a defect-enriched MoS 2 /MoO 3 surface. Large negative adsorption energies (for NH 3 ) of −344 and −519 meV, respectively, reflect that the adsorption process is feasible, and mechanism change from physisorption to chemisorption is predicted. Bader scheme was employed to evaluate the charge transfer between the NH 3 molecule and the pristine (defect-enriched) MoS 2 /MoO 3 surface and gave an amount of 0.073e (0.010e). Therefore, these results collectively justify the use of the MoS 2 /MoO 3 composite as a selective NH 3 sensor that can operate in humid air and environmental monitoring applications where such conditions exist.

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“…Therefore, combining MoS 2 with unique material is important for achieving an enhanced sensing performance. For instance, WO 3 /MoS 2 composites have been developed, and the nanocomposite exhibits excellent ammonia and hydrogen sulfide sensing properties (Singh et al, 2020, Singh et al, 2021. However, these sensor devices function only at temperatures higher than 200 °C. Besides, most of the previously developed hydrogen gas sensor exhibited low sensor response.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient MoS2/CsxWO3 Nanocomposite Hydrogen Gas Sensors

Shrisha

Motora

et al. 2022

Front. Mater.

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Hydrogen gas sensors are important because of the significant use of hydrogen in industrial and commercial applications. In this study, we synthesized a novel CsxWO3/MoS2 nanocomposite using a solvothermal method. The samples were spin-coated on Si/SiO2 substrates, and the sensors were fabricated with interdigital electrodes. The hydrogen gas sensing properties of the sensor were investigated. CsxWO3/MoS2 exhibited an outstanding hydrogen gas sensing ability at room temperature. In particular, the nanocomposite comprising 15 wt.% MoS2 (15% CsxWO3/MoS2) showed a 51% response to hydrogen gas at room temperature. Further, it exhibited an excellent cyclic stability for hydrogen gas sensing, which is crucial for practical applications. Therefore, this study facilitates the development of effective and efficient hydrogen gas sensors operable at room temperature.

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A sensitive H2S sensor using MoS2/WO3 composite

Cited by 14 publications

References 5 publications

MoS₂/WO₃Nanosheets for Detection of Ammonia

MoS₂/WO₃Nanosheets for Detection of Ammonia

MoS₂/MoO₃ Nanocomposite for Selective NH₃ Detection in a Humid Environment

Highly Efficient MoS2/CsxWO3 Nanocomposite Hydrogen Gas Sensors

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A sensitive H2S sensor using MoS2/WO3 composite

Cited by 14 publications

References 5 publications

MoS2/WO3Nanosheets for Detection of Ammonia

MoS2/WO3Nanosheets for Detection of Ammonia

MoS2/MoO3 Nanocomposite for Selective NH3 Detection in a Humid Environment

Highly Efficient MoS2/CsxWO3 Nanocomposite Hydrogen Gas Sensors

Contact Info

Product

Resources

About

MoS₂/WO₃Nanosheets for Detection of Ammonia

MoS₂/WO₃Nanosheets for Detection of Ammonia

MoS₂/MoO₃ Nanocomposite for Selective NH₃ Detection in a Humid Environment