A highly selective and sensitive H2S sensor at low temperatures based on Cr-doped α-Fe2O3 nanoparticles

A robust synthesis approach to develop CuO/ZnO nanocomposites using microwave-epoxide-assisted hydrothermal synthesis and their proficiency toward H 2 S gas-sensing application are reported. The lowcost metal salts (Cu and Zn) as precursors in aqueous media and epoxide (propylene oxide) as a proton scavenger/gelation agent are used for the formation of mixed metal hydroxides. The obtained sol was treated using the microwave hydrothermal process to yield the high-surface area (34.71 m 2 /g) CuO/ZnO nanocomposite. The developed nanocomposites (1.25−10 mol % Cu doping) showcase hexagonal ZnO and monoclinic CuO structures, with an average crystallite size in the range of 18−29 nm wrt Cu doping in the ZnO matrix. The optimized nanocomposite (2.5 mol % Cu doping) showed a lowest crystallite size of 21.64 nm, which reduced further to 18.06 nm upon graphene oxide addition. Morphological analyses (scanning electron microscopy and transmission electron microscopy) exhibited rounded grains along with copious channels typical for sol−gel-based materials . Elemental mapping displayed the good dispersion of Cu in the ZnO matrix. When these materials are employed as a gas sensor, they demonstrated high sensitivity and selectivity toward H 2 S gas in comparison with the reducing gases and volatile organic compounds under investigation. The systematic doping of Cu in the ZnO matrix exhibited an improved response from 76.66 to 94.28%, with reduction in operating temperature from 300 to 250 °C. The 2.5 mol % doped Cu in ZnO was found to impart a response of 23 s for 25 ppm of H 2 S. Gas-sensing properties are described using an interplay of epoxide-assisted sol−gel chemistry and structural and morphological properties of the developed material.

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“…As a result, the width of the depletion layer decreases and thus the resistance as well. The possible reactions are as follows …”

Section: Resultsmentioning

confidence: 99%

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H₂S Gas Sensors

et al. 2020

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“…and produces an odor like rotten eggs. [144,204,205] Depending upon exposure concentration and duration, H 2 S may either cause corneal erosion or even cause death. [144] Hence, detection of H 2 S gas is necessary for health and safety.…”

Section: Gaseous Pollutantsmentioning

confidence: 99%

Recent Advancements in Development of Wearable Gas Sensors

Bag

Lee

2021

Adv Materials Technologies

139

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In the era of the Internet of Things, wearable technologies are expected to become an indispensable part of daily life. In recent times, highly sensitive, flexible, and stretchable electronic gas sensors are gaining tremendous interest due to their applicability in wearable electronics applications. The construction of wearable gas sensors are reviewed for real‐time, highly sensitive, and selective detection of hazardous gases at room temperature (RT) that can be laminated onto a human body or integrated with body‐worn textile or other consumer products, utilizing carbon nanomaterials, conductive polymers, 2D nanostructured materials, and their composites. Sensing materials, transduction techniques, and substrates for high‐performance wearable gas sensing are discussed in detail. The critical challenges for future development of wearable gas sensors are presented. Wearable gas sensors are believed to have great potential in environmental monitoring, healthcare, public safety, security, as well as food quality monitoring.

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“…Research on MOS is also highly inspired by various desirable traits such as improved sensitivity [8], enhanced adsorption ability [9], extensive catalytic activity [10] and high thermodynamic stability [11] towards the analyte gases. Yet obtaining all of these characteristics using a single metal oxide has proved to be difficult.…”

Section: Introductionmentioning

confidence: 99%

Path Way For Electrical Conduction In ZnO Basedternary Nanocomposite Room Temperature Ethanol Sensors

Muthukumaravel¹,

Mangamma

Arumugam

et al. 2021

Preprint

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In the present investigations, the samples such as zinc oxide, tin oxide, vanadium oxide and their ternary combinations prepared by hydrothermal route were characterised using the state-of-the-art facilities and were systematically analysed. The interface properties between the grain and grain boundaries of these oxides were studied using Conductive atomic force microscopic (CAFM) studies. From the detailed investigations on topography and I-V characteristics, it is revealed that, zinc-tin-vanadium oxide nanocomposite with smaller barrier height of 0.189 eV exhibited pronounced response magnitude of 98.96 % at a faster rate of 32 s at room temperature. The outstanding ethanol sensing property of the ternary nanocomposite is attributed to the hierarchical morphology with large surface area, the formation of heterojunction at the interface, tuning the schottky barrier height, depletion layer manipulation and the electronic effects.

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A highly selective and sensitive H₂S sensor at low temperatures based on Cr-doped α-Fe₂O₃ nanoparticles

Abstract: Cr-doped α-Fe2O3 nanoparticles were synthesized by one-step hydrothermal reaction and showed high sensitivity and selectivity to H2S at low temperature.

Cited by 32 publications

References 48 publications

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H₂S Gas Sensors

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H₂S Gas Sensors

Recent Advancements in Development of Wearable Gas Sensors

Path Way For Electrical Conduction In ZnO Basedternary Nanocomposite Room Temperature Ethanol Sensors

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A highly selective and sensitive H2S sensor at low temperatures based on Cr-doped α-Fe2O3 nanoparticles

Abstract: Cr-doped α-Fe2O3 nanoparticles were synthesized by one-step hydrothermal reaction and showed high sensitivity and selectivity to H2S at low temperature.

Cited by 32 publications

References 48 publications

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H2S Gas Sensors

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H2S Gas Sensors

Recent Advancements in Development of Wearable Gas Sensors

Path Way For Electrical Conduction In ZnO Basedternary Nanocomposite Room Temperature Ethanol Sensors

Contact Info

Product

Resources

About

A highly selective and sensitive H₂S sensor at low temperatures based on Cr-doped α-Fe₂O₃ nanoparticles

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H₂S Gas Sensors

Microwave-Epoxide-Assisted Hydrothermal Synthesis of the CuO/ZnO Heterojunction: a Highly Versatile Route to Develop H₂S Gas Sensors