Gas Sensing Performance and Mechanism of CuO(p)-WO3(n) Composites to H2S Gas

In this work, the compositional optimization in copper oxide/tungsten trioxide (CuO/WO3) composites was systematically studied for hydrogen sulfide (H2S) sensing. The response of CuO/WO3 composites changes from p-type to n-type as the CuO content decreases. Furthermore, the p-type response weakens while the n-type response strengthens as the Cu/W molar ratio decreases from 1:0 to 1:10. The optimal Cu/W molar ratio is 1:10, at which the sensor presents the ultrahigh n-type response of 1.19 × 105 to 20 ppm H2S gas at 40 °C. Once the temperature rises from 40 °C to 250 °C, the CuO/WO3 (1:1) sensor presents the p-n response transformation, and the CuO/WO3 (1:1.5) sensor changes from no response to n-type response, because the increased temperature facilitates the Cu-S bonds break and weakens the p-type CuO contribution to the total response, such that the CuS bond decomposition by a thermal effect was verified by a Raman analysis. In addition, with a decrease in CuO content, the CuO is transformed from partly to completely converting to CuS, causing the resistance of CuO to decrease from increasing and, hence, a weakening mode of p-CuO and n-WO3 to the total response turns to a synergistic mode to it.

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Simple post-synthesis of mesoporous p-type Co3O4 nanochains for enhanced H2S gas sensing performance

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2018.05.026 ◽

2018 ◽

Vol 270 ◽

pp. 158-166 ◽

Cited By ~ 26

Author(s):

Pham Long Quang ◽

Nguyen Duc Cuong ◽

Tran Thai Hoa ◽

Hoang Thai Long ◽

Chu Manh Hung ◽

...

Keyword(s):

Gas Sensing ◽

Post Synthesis ◽

P Type ◽

Sensing Performance

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Discriminable Sensing Response Behavior to Homogeneous Gases Based on n-ZnO/p-NiO Composites

Nanomaterials ◽

10.3390/nano10040785 ◽

2020 ◽

Vol 10 (4) ◽

pp. 785 ◽

Cited By ~ 24

Author(s):

Wen-Dong Zhou ◽

Davoud Dastan ◽

Jing Li ◽

Xi-Tao Yin ◽

Qi Wang

Keyword(s):

Gas Sensors ◽

Gas Sensing ◽

Sol Gel ◽

High Sensitivity ◽

Oxide Semiconductor ◽

Sensing Properties ◽

Gas Sensing Properties ◽

P Type ◽

Type Response ◽

Properties Of Composites

Metal oxide semiconductor (MOS) gas sensors have the advantages of high sensitivity, short response-recovery time and long-term stability. However, the shortcoming of poor discriminability of homogeneous gases limits their applications in gas sensors. It is well-known that the MOS materials have similar gas sensing responses to homogeneous gases such as CO and H2, so it is difficult for these gas sensors to distinguish the two gases. In this paper, simple sol–gel method was employed to obtain the ZnO–xNiO composites. Gas sensing performance results illustrated that the gas sensing properties of composites with x > 0.425 showed a p-type response to both CO and H2, while the gas sensing properties of composites with x < 0.425 showed an n-type response to both CO and H2. However, it was interesting that ZnO–0.425NiO showed a p-type response to CO but an discriminable response (n-type) to H2, which indicated that modulating the p-type or n-type semiconductor concentration in p-n composites could be an effective method with which to improve the discriminability of this type of gas sensor regarding CO and H2. The phenomenon of the special gas sensing behavior of ZnO–0.425NiO was explained based on the experimental observations and a range of characterization techniques, including XRD, HRTEM and XPS, in detail.

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A Room Temperature Gas Sensor Based on Sulfonated SWCNTs for the Detection of NO and NO2

Sensors ◽

10.3390/s19051116 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1116 ◽

Cited By ~ 6

Author(s):

Eusebiu Ionete ◽

Stefan Spiridon ◽

Bogdan Monea ◽

Elena Stratulat

Keyword(s):

Room Temperature ◽

Gas Sensing ◽

Electrical Response ◽

Long Term Stability ◽

Sensing Applications ◽

Specific Configuration ◽

P Type ◽

Walled Carbon Nanotubes ◽

Type Response

The electrical response of sulfonated single-walled carbon nanotubes (SWCNTs) to NO and NO2, for gas sensing applications, at room temperature, is reported in this work. A specific configuration based on SWCNT deposition between double pair configuration gold electrodes, supported on a substrate, was considered for the sensing device; employed characterization technique where FTIR and SEM. The experimental results showed a p-type response of the sulfonated SWCNTs, with decrease in resistance, under exposure to NO gas (40–200 ppb) and NO2 (40–200 ppb). Also, the sensor responses to successive exposures at NO2 800 ppb together with investigation of long term stability, at 485 ppb for NO, are reported. The reaction mechanism in case of NO and NO2 detection with sulfonated SWCNTs is presented.

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Gas sensing properties and p-type response of ALD TiO2coated carbon nanotubes

Nanotechnology ◽

10.1088/0957-4484/26/2/024004 ◽

2014 ◽

Vol 26 (2) ◽

pp. 024004 ◽

Cited By ~ 27

Author(s):

Catherine Marichy ◽

Nicola Donato ◽

Mariangela Latino ◽

Marc Georg Willinger ◽

Jean-Philippe Tessonnier ◽

...

Keyword(s):

Carbon Nanotubes ◽

Gas Sensing ◽

Sensing Properties ◽

Gas Sensing Properties ◽

P Type ◽

Type Response

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High-Performance Gas Sensor of Polyaniline/Carbon Nanotube Composites Promoted by Interface Engineering

Sensors ◽

10.3390/s20010149 ◽

2019 ◽

Vol 20 (1) ◽

pp. 149 ◽

Cited By ~ 9

Author(s):

Weiyu Zhang ◽

Shuai Cao ◽

Zhaofeng Wu ◽

Min Zhang ◽

Yali Cao ◽

...

Keyword(s):

High Performance ◽

Structural Changes ◽

Gas Sensing ◽

Response Times ◽

Limit Of Detection ◽

Hierarchical Structures ◽

Cost Effective ◽

One Dimensional ◽

P Type ◽

Sensing Performance

Inspired by the enhanced gas-sensing performance by the one-dimensional hierarchical structure, one-dimensional hierarchical polyaniline/multi-walled carbon nanotubes (PANI/CNT) fibers were prepared. Interestingly, the simple heating changed the sensing characteristics of PANI from p-type to n-type and n-type PANI and p-type CNTs form p–n hetero junctions at the core–shell interface of hierarchical PANI/CNT composites. The p-type PANI/CNT (p-PANI/CNT) and n-type PANI/CNT (n-PANI/CNT) performed the higher sensitivity to NO2 and NH3, respectively. The response times of p-PANI/CNT and n-PANI/CNT to 50 ppm of NO2 and NH3 are only 5.2 and 1.8 s, respectively, showing the real-time response. The estimated limit of detection for NO2 and NH3 is as low as to 16.7 and 6.4 ppb, respectively. After three months, the responses of p-PANI/CNT and n-PANI/CNT decreased by 19.1% and 11.3%, respectively. It was found that one-dimensional hierarchical structures and the deeper charge depletion layer enhanced by structural changes of PANI contributed to the sensitive and fast responses to NH3 and NO2. The formation process of the hierarchical PANI/CNT fibers, p–n transition, and the enhanced gas-sensing performance were systematically analyzed. This work also predicts the development prospects of cost-effective, high-performance PANI/CNT-based sensors.

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Pt Nanoparticles Sensitized Ordered Mesoporous WO 3 Semiconductor: Gas Sensing Performance and Mechanism Study

Advanced Functional Materials ◽

10.1002/adfm.201705268 ◽

2017 ◽

Vol 28 (6) ◽

pp. 1705268 ◽

Cited By ~ 87

Author(s):

Junhao Ma ◽

Yuan Ren ◽

Xinran Zhou ◽

Liangliang Liu ◽

Yongheng Zhu ◽

...

Keyword(s):

Gas Sensing ◽

Pt Nanoparticles ◽

Mechanism Study ◽

Ordered Mesoporous ◽

Performance And Mechanism ◽

Sensing Performance

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Sensors: Pt Nanoparticles Sensitized Ordered Mesoporous WO 3 Semiconductor: Gas Sensing Performance and Mechanism Study (Adv. Funct. Mater. 6/2018)

Advanced Functional Materials ◽

10.1002/adfm.201870040 ◽

2018 ◽

Vol 28 (6) ◽

pp. 1870040 ◽

Cited By ~ 2

Author(s):

Junhao Ma ◽

Yuan Ren ◽

Xinran Zhou ◽

Liangliang Liu ◽

Yongheng Zhu ◽

...

Keyword(s):

Gas Sensing ◽

Pt Nanoparticles ◽

Mechanism Study ◽

Ordered Mesoporous ◽

Performance And Mechanism ◽

Sensing Performance

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The highly improved gas-sensing performance of α-Fe2O3-decorated NiO nanowires and the interfacial effect of p–n heterojunctions

Journal of Materials Chemistry C ◽

10.1039/c9tc06614d ◽

2020 ◽

Vol 8 (11) ◽

pp. 3855-3864

Author(s):

L. Wang ◽

B. Hong ◽

H. D. Chen ◽

J. C. Xu ◽

Y. B. Han ◽

...

Keyword(s):

Gas Sensing ◽

Interfacial Effect ◽

P Type ◽

Sensing Performance

Mesoporous n-type α-Fe2O3-decorated p-type NiO NWs were synthesized by two-step nanocasting method, and the influence of the heterogeneous α-Fe2O3 decoration on the components, microstructure and gas-sensing performance of NiO NWs was discussed.

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A STUDY OF THE CHARACTERISTICS AND SELECTION OF DOPED MATERIALS FOR NIO TO OPTIMIZE GAS SENSING

International Journal of Advanced Research ◽

10.21474/ijar01/13399 ◽

2021 ◽

Vol 9 (09) ◽

pp. 240-241

Author(s):

Monika Singh ◽

◽

Shriom Mishra ◽

Shiksha Jain ◽

Mukul Saxena ◽

...

Keyword(s):

Gas Sensors ◽

Noble Metals ◽

Gas Sensing ◽

Human Life ◽

Transition Metal Dichalcogenide ◽

Surface Areas ◽

Doped Materials ◽

P Type ◽

Selection Of ◽

Sensing Performance

Gas sensing of hazardous has become a great challenge for several decades. Recently, technical and industrial advancements uninterruptedly produce the emission of hazardous and poisonous gases that are detrimental to human life as a consequence gas detecting devices that are extremely sensitive and selective to such gases are in a high demand. Presently, gas sensors based on p-type NiO are attracting more attention, because of its outstanding repeatability, high specific surface areas, strong sensitivity, cheap cost and environmental friendly. Herein, we evaluated the various production techniques on p-type NiO nanostructures and their use as gas sensors. The basic gas sensing process linked to the p-type NiO is briefly described. The impacts of noble metals, transition metals, and transition metal dichalcogenide and phosphors materials on the NiO gas sensing performance are also examined in depth. With various level of doping, heterostructure NiO depicts improved sensing performance for gases like HCHO, NH3, NO2, C2H5OH and H2. The arrangement of different semiconductor metal oxides to create heterostructures which further enhance the selectivity and sensitivity of the sensing parameters is also addressed. Heterostructure NiO has enhanced sensing capability for gases such as HCHO, NH3, NO2, C2H5OH, and H2 with varying levels of doping. There are many literatures on heterostructures linked to NiO based sensor significantly in last decade. The current work will aid researchers in the selection of doped materials for NiO gas sensors in order to enhance sensitivity.

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