TiO2-Based Nanoheterostructures for Promoting Gas Sensitivity Performance: Designs, Developments, and Prospects

Wang, Yuan; Wu, Tao; Zhou, Yun; Meng, Chao; Zhu, Weiliang; Liu, Lixin

doi:10.3390/s17091971

Cited by 76 publications

(47 citation statements)

References 172 publications

(217 reference statements)

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“…Among many other inorganic semiconductor-based structures, TiO 2 -based structures are often used for the development of gas-sensing devices due to their sensing properties [1]. Titanium dioxide (TiO 2 ) is an n-type semiconductor, which exists in three main phases (i) anatase, (ii) rutile and (iii) brookite with bandgaps of 3.02, 3.23, and 2.96 eV, respectively [2].…”

Section: Introductionmentioning

confidence: 99%

TiO2-x/TiO2-Structure Based ‘Self-Heated’ Sensor for the Determination of Some Reducing Gases

Ramanavičius

Tereshchenko

Karpicz

et al. 2019

Sensors

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In this research we report the gas-sensing properties of TiO2-x/TiO2-based hetero-structure, which was ‘self-heated’ by current that at constant potential passed through the structure. Amperometric measurements were applied for the evaluation of sensor response towards ethanol, methanol, n-propanol and acetone gases/vapours. The sensitivity towards these gases was based on electrical resistance changes, which were determined by amperometric measurements of current at fixed voltage applied between Pt-based contacts/electrodes deposited on the TiO2-x/TiO2-based layer. X-ray diffraction (XRD) analysis revealed the formation of TiO2-x/TiO2-based hetero-structure, which is mainly based on Ti3O5/TiO2 formed during the hydro-thermal oxidation-based sensing-layer preparation process. Additionally, photoluminescence and time-resolved photoluminescence decay kinetics-based signals of this sensing structure revealed the presence of TiO2 mainly in the anatase phase in the TiO2-x/TiO2-based hetero-structure, which was formed at 400 °C annealing temperature. The evaluation of TiO2-x/TiO2-based gas-sensing layer was performed at several different temperatures (25 °C, 72 °C, 150 °C, 180 °C) and at these temperatures different sensitivity to the aforementioned gaseous materials was determined.

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Section: Introductionmentioning

confidence: 99%

TiO2-x/TiO2-Structure Based ‘Self-Heated’ Sensor for the Determination of Some Reducing Gases

Ramanavičius

Tereshchenko

Karpicz

et al. 2019

Sensors

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“…In particular, the different morphologies of ZnO NRs significantly affect the detection property of NO 2 gas sensors [11]; moreover, ZnO NRs-based sensors have a very low detection limit (10 ppm) for NO 2 gas at 250 • C, along with short response and recovery times [12]. TiO 2 is another very promising material for NO 2 gas detection because of its high temperature stability, harsh environment tolerance, and catalytic properties [13]. Therefore, combined ZnO/TiO 2 nanostructures can achieve better physical and chemical properties than of the corresponding individual ones because of the modification of their electronic states [14,15].…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet Photoactivated Room Temperature NO2 Gas Sensor of ZnO Hemitubes and Nanotubes Covered with TiO2 Nanoparticles

et al. 2020

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Prolonged exposure to NO2 can cause lung tissue inflammation, bronchiolitis fibrosa obliterans, and silo filler’s disease. In recent years, nanostructured semiconducting metal oxides have been widely used to fabricate gas sensors because of their unique structure and surface-to-volume ratio compared to layered materials. In particular, the different morphologies of ZnO-based nanostructures significantly affect the detection property of NO2 gas sensors. However, because of the large interaction energy of chemisorption (1–10 eV), metal oxide-based gas sensors are typically operated above 100 °C, overcoming the energy limits to attain high sensitivity and fast reaction. High operating temperature negatively affects the reliability and durability of semiconductor-based sensors; at high temperature, the diffusion and sintering effects at the metal oxide grain boundaries are major factors causing undesirable long-term drift problems and preventing stability improvements. Therefore, we demonstrate NO2 gas sensors consisting of ZnO hemitubes (HTs) and nanotubes (NTs) covered with TiO2 nanoparticles (NPs). To operate the gas sensor at room temperature (RT), we measured the gas-sensing properties with ultraviolet illumination onto the active region of the gas sensor for photoactivation instead of conventional thermal activation by heating. The performance of these gas sensors was enhanced by the change of barrier potential at the ZnO/TiO2 interfaces, and their depletion layer was expanded by the NPs formation. The gas sensor based on ZnO HTs showed 1.2 times higher detection property than those consisting of ZnO NTs at the 25 ppm NO2 gas.

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“…Among various n-type semiconductors, TiO 2 has been widely studied for gas sensing (Zhao et al, 2015;Wang et al, 2017). A TiO 2 ordered nanotube was proved to have exceptionally high response to hydrogen owing to its unique hierarchical morphology (Varghese et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Improving Hydrogen Sensing Performance of TiO2 Nanotube Arrays by ZnO Modification

Xun

2019

Front. Mater.

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In this work, anodization was utilized to synthesize highly ordered TiO 2 nanotube arrays, and ZnO was successfully decorated onto the surface of as-prepared TiO 2 nanotubes via a facile impregnation method. The gas sensing performance of a TiO 2 @ZnO composite was systematically studied. At a working temperature of 300 • C, the response of TiO 2 @ZnO to 100 ppm H 2 was ∼340, 2.7 times larger than that of pristine TiO 2 . A power-law relationship between the response and H 2 concentration was observed. In addition, the response time was significantly reduced by four times, and improved selectivity to H 2 was achieved. The highly improved sensing performance of TiO 2 nanotubes by ZnO decoration may be attributed to the enhanced oxygen adsorption and formation of n-n heterojunctions.

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TiO2-Based Nanoheterostructures for Promoting Gas Sensitivity Performance: Designs, Developments, and Prospects

Cited by 76 publications

References 172 publications

TiO2-x/TiO2-Structure Based ‘Self-Heated’ Sensor for the Determination of Some Reducing Gases

TiO2-x/TiO2-Structure Based ‘Self-Heated’ Sensor for the Determination of Some Reducing Gases

Ultraviolet Photoactivated Room Temperature NO2 Gas Sensor of ZnO Hemitubes and Nanotubes Covered with TiO2 Nanoparticles

Improving Hydrogen Sensing Performance of TiO2 Nanotube Arrays by ZnO Modification

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