Correlation between donating or accepting electron behavior of the adsorbed CO or H2 and its oxidation over TiO2 under ultraviolet light irradiation

Peng, Xiaoying; He, Zhoujun; Yang, Kai; Chen, Xun; Wang, Xuxu; Dai, Wenxin; Fu, Xianzhi

doi:10.1016/j.apsusc.2015.11.048

Cited by 28 publications

(14 citation statements)

References 47 publications

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“…Here H 2 molecules showed a lower adsorption energy than the Fermi level of TiO 2 . Thus, it acted as an electron acceptor which caused the resistance of TiO 2 to increase ( Figure 18 ) [ 52 ]. A similar result was observed by Wang, who used vertically aligned ZnO nanowires for CO sensing with light illumination at low intensity.…”

Section: Pure Metal Oxide Materials For Gas Sensingmentioning

confidence: 99%

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Light-Activated Metal Oxide Gas Sensors: A Review

Fang

2017

Micromachines

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Conductometric gas sensors facilitated by photons have been investigated for decades. Light illumination may enhance device attributes including operational temperature, sensing sensitivity and selectivity. This paper aims to provide an overview on the progress of light-activated gas sensors, with a specific focus on sensors based on metal oxides. The material systems that have been studied include pure metal oxides, heterostructures of semiconductor-metal oxides and metal-metal oxides, and metal oxides with dopant. Other reported works on the use of different nanostructures such as one-dimensional and porous nanostructures, study of sensing mechanisms and the interplay between various factors are also summarized. Possible directions for further improvement of sensing properties, through optimizing the size of nanomaterials, film thickness, light intensity and wavelength are discussed. Finally, we point out that the main challenge faced by light-activated gas sensors is their low optical response, and we have analyzed the feasibility of using localized surface plasmon resonance to solve this drawback. This article should offer readers some key and instructive insights into the current and future development of light-activated gas sensors.

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Section: Pure Metal Oxide Materials For Gas Sensingmentioning

confidence: 99%

“…The adsorption of H 2 causes the elevation of Fermi level (from EF to EF* (a quasi-Fermi level)) under UV irradiation, resulting in H 2 accepting electrons from TiO 2 , while CO still donate electrons to TiO 2 . Reproduced with permission from [ 52 ].…”

Section: Figurementioning

confidence: 99%

Light-Activated Metal Oxide Gas Sensors: A Review

Fang

2017

Micromachines

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“…However, UV light might cause the change in the surface state of TiO 2 (in fact, the process of UV irradiating TiO 2 can be regarded as a process of TiO 2 reduced by UV light), the generation of electrons, the recombination of electrons with holes, the capture of electrons by defects or surface hydroxyls, and the transfer of electrons will make some changes with the duration of introducing UV light, especially under the bias voltage. Therefore, the impedance of TiO 2 sensor sample increased slowly with the duration of UV irradiation [ 57 ]. With the introduction of H 2 , the impedance of TiO 2 -I sample decreased rapidly but that of TiO 2 -D sample increases.…”

Section: Resultsmentioning

confidence: 99%

“…With the introduction of H 2 , the impedance of TiO 2 -I sample decreased rapidly but that of TiO 2 -D sample increases. The latter indicates that the adsorbed H 2 could offer electrons to TiO 2 -I but accept electrons from the TiO 2 -D sample [ 57 ]. Moreover, TiO 2 -I exhibited a higher response to H 2 than TiO 2 -D ( Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

“…Obviously, it could be observed that the photocurrent of the TiO 2 (in-situ) electrode is much larger than the one obtained with the TiO 2 (commercial) electrode. With the irradiation prolonged, more and more photo-generated electrons and holes recombined or be captured on TiO 2 surface due to the reduction of TiO 2 by UV light [ 57 ], which resulted in the photocurrent decay. Note that the photocurrent value of TiO 2 (in-situ) is larger than that of TiO 2 (commercial), indicating that the recombination rate of TiO 2 (in-situ) is lower than that of TiO 2 (commercial).…”

Section: Resultsmentioning

confidence: 99%

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Comparative Study of Two Different TiO2 Film Sensors on Response to H2 under UV Light and Room Temperature

Peng

Wang

Huang

et al. 2016

Sensors

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An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature.

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Hydrothermal synthesis of hierarchical ZnO microspheres and UV-light-assisted CH4 sensing properties

Wang,

Zhang

et al. 2023

Appl. Phys. A

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Correlation between donating or accepting electron behavior of the adsorbed CO or H2 and its oxidation over TiO2 under ultraviolet light irradiation

Cited by 28 publications

References 47 publications

Light-Activated Metal Oxide Gas Sensors: A Review

Light-Activated Metal Oxide Gas Sensors: A Review

Comparative Study of Two Different TiO2 Film Sensors on Response to H2 under UV Light and Room Temperature

Hydrothermal synthesis of hierarchical ZnO microspheres and UV-light-assisted CH4 sensing properties

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