Field emission energy distribution studies of single multi-walled carbon nanotube emitter with gas adsorptions

Zhu, Wei; Qian, Weijin; Liu, Ruizi; Huang, Weijun; Luo, Haijun; Dong, Changkun

doi:10.1016/j.vacuum.2022.110933

Cited by 5 publications

(1 citation statement)

References 29 publications

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“…In recent years, gas sensors have attracted immense attention as they are safe and can be used to address several environmental issues [1,2]. The adsorption properties of gas molecules present on crystal planes are being increasingly studied in recent times [3][4][5]. Many metal-based semiconductor oxides have been used to research gas-sensitive materials, such as SnO 2 , ZnO, and TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Co2+ Doping and Molecular Adsorption Behavior of Anatase TiO2 (001) Crystal Plane

Fang¹,

Li²,

Bai³

et al. 2022

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TiO2 (001) crystal plane exhibits molecular adsorption and photocatalytic activity. The loading capacity of reactive oxygen species present on crystal planes helps in the significant improvement of catalytic activity. The methods of synthesis and conditions of existence significantly affect the molecular adsorption properties of crystal planes, which in turn affects the ability of the system to load reactive oxygen species. Herein, we report the simulation of the molecular adsorption behavior on the TiO2 (001) using the density functional theory technique. The results show that the crystal plane doped with Co2+ produces an oxygen defect and chemisorbs O2 molecules present in the vicinity. Under conditions of adequate O2 concentration, the second O2 molecule is chemisorbed. This significantly improves the ability of the crystal plane to store oxygen. However, the undoped planes adsorb H2O molecules and undergo hydroxylation under the synthesis and processing conditions. The ability to adsorb O2 molecules is poor. The doping of Co2+ increases the electrical conductivity of the crystal plane and the electrical sensitivity of adsorbed O2 molecules, which is beneficial to the further improvement of the catalytic activity of the system. Fourier transform infrared spectroscopy (FTIR), and electrochemical impedance spectroscopy (EIS) techniques were used to confirm these results. The results indicate that the adsorption capacity of O2 present on the TiO2 (001) crystal plane can be changed by Co2+ doping to improve the catalytic activity of the crystal plane.

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Section: Introductionmentioning

confidence: 99%

Co2+ Doping and Molecular Adsorption Behavior of Anatase TiO2 (001) Crystal Plane

Fang¹,

Li²,

Bai³

et al. 2022

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Miniature vacuum sensor based on gas adsorptions from carbon nanotube field emitters

Kang

Qian

Liu

et al. 2023

Vacuum

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Metal- and Nitrogen-Codoped Carbon Nanotube Field Emitters for Low-Pressure Hydrogen Sensing

Chen,

Luo,

Qian

et al. 2024

ACS Appl. Nano Mater.

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Metal-doped carbon nanotubes (CNTs) have great potential in hydrogen detection because of their large specific surface areas, good catalytic activity, and numerous defect states. However, CNT-based sensing materials have the problem of insufficient hydrogen sensing responsiveness at low pressure, and the effects of different types of catalytic metals on low-pressure hydrogen sensing are still unknown. In this paper, low-pressure hydrogen sensing properties were studied by construction of Fe/Co/Ni-and nitrogen-codoped CNT cathodes, and the pressure was detected from 10 −7 to 10 −4 Pa. In addition, the hydrogen sensing mechanism was studied using first-principles simulations. The experimental results suggested that the Co−N-codoped CNT cathode exhibits the best hydrogen detection properties with a field mission current increase of 224% in 5 min. Furthermore, the FE current could increase 145% in 1 min at a pressure of 4.28 × 10 −4 Pa, promising for quick detection. The simulation revealed that the work functions of metal-and nitrogen-codoped CNTs decreased rapidly with the increase of hydrogen atoms, leading to the obvious improvement of hydrogen sensing properties. These conclusions not only bring good insights into the hydrogen sensing enhancement mechanism for metal−nitrogen-codoped CNT cathodes but also provide a promising way to develop practical cathodes for quick low-pressure hydrogen detections.

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Field emission energy distribution studies of single multi-walled carbon nanotube emitter with gas adsorptions

Cited by 5 publications

References 29 publications

Co2+ Doping and Molecular Adsorption Behavior of Anatase TiO2 (001) Crystal Plane

Co2+ Doping and Molecular Adsorption Behavior of Anatase TiO2 (001) Crystal Plane

Miniature vacuum sensor based on gas adsorptions from carbon nanotube field emitters

Metal- and Nitrogen-Codoped Carbon Nanotube Field Emitters for Low-Pressure Hydrogen Sensing

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