scholarly journals Disordered Adsorbed Water Layers on TiO2 Nanoparticles under Subsaturated Humidity Conditions at 235 K

2019 ◽  
Vol 10 (23) ◽  
pp. 7433-7438 ◽  
Author(s):  
Fabrizio Orlando ◽  
Luca Artiglia ◽  
Huanyu Yang ◽  
Xiangrui Kong ◽  
Kanak Roy ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Adsorbed Water ◽  
Water Layers

Vertical and Lateral Order in Adsorbed Water Layers on Anatase TiO2(101)

Langmuir ◽  
2004 ◽  
Vol 20 (19) ◽  
pp. 8379-8384 ◽  
Author(s):  
Antonio Tilocca ◽  
Annabella Selloni
Keyword(s):  
Adsorbed Water ◽  
Anatase Tio2 ◽  
Water Layers

Contact Forces between TiO2Nanoparticles Governed by an Interplay of Adsorbed Water Layers and Roughness

Langmuir ◽  
2015 ◽  
Vol 31 (41) ◽  
pp. 11288-11295 ◽  
Author(s):  
Jens Laube ◽  
Samir Salameh ◽  
Michael Kappl ◽  
Lutz Mädler ◽  
Lucio Colombi Ciacchi
Keyword(s):  
Adsorbed Water ◽  
Contact Forces ◽  
Water Layers

scholarly journals RH Sensing by Means of TiO2 Nanoparticles: A Comparison among Different Sensing Techniques Based on Modeling and Chemical/Physical Interpretation

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 89 ◽  
Author(s):  
Irene Cappelli ◽  
Ada Fort ◽  
Anna Lo Grasso ◽  
Enza Panzardi ◽  
Marco Mugnaini ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Water Adsorption ◽  
Active Material ◽  
Volume Ratio ◽  
Adsorbed Water ◽  
Underlying Mechanism ◽  
Water Vapor Adsorption ◽  
Sensor Technology ◽  
Electrical Behavior ◽  
Advantages And Disadvantages

TiO2 nanoparticles coating has been proven to be an extremely performing sensing material for relative humidity (RH) measurements. The chemical activity of TiO2 toward water vapor adsorption and the very large surface to volume ratio typical of nanostructures are ideal characteristics for the development of RH fast and sensitive sensors. Different sensor technologies can be used in conjunction with this material to realize devices with satisfactory performance. In this paper, the authors aim to describe and discuss the main different possible choices and highlight the advantages and disadvantages, and linking them both to the underlying mechanism of water adsorption on the TiO2 sensing layer and to the modification of the electrical behavior due to the water adsorption. In particular, the authors start from results obtained by depositing TiO2 nanoparticles on a novel MEMS microbalance operating at low frequency, which allows to sense only the adsorbed water mass, and they exploit the sensor output to obtain a dynamic model of the water adsorption. They also link these results to those obtained with a Quartz Crystal Microbalance (QCM) functionalized with the same material operating at 10 MHz as a part of an oscillator. Finally, they establish a link with the results obtained by an RH impedance sensor, which exploits the same active material and the same deposition technique. With this sensor technology, the conductive and electrical behavior of the sensing and adsorbed films play a role. The whole work tries to unravel the different phenomena that contribute to the response of RH sensors not only based on TiO2 nanoparticles but also, more generally, based on nanostructured metal oxide materials.

Hydromechanical effects: (II) on the water-Na-smectite system

Clay Minerals ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 537-544 ◽  
Author(s):  
M. Al-mukhtar ◽  
Y. Qi ◽  
J . -F. Alcover ◽  
J . Conard ◽  
F. Bergaya
Keyword(s):  
Water Content ◽  
Mechanical Stress ◽  
Adsorbed Water ◽  
Bulk Water ◽  
Water Volume ◽  
X Ray Diffraction ◽  
Applied Water ◽  
X Ray ◽  
Water Layers ◽  
Different Types

AbstractThe localization and number of the different types of water in two Na-smectites (Laponite and hectorite) were studied as a function of the hydromechanical stresses applied. Water volume variation was obtained by macroscopic oedometric tests. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) were used to study water-smectite interactions. The TGA results show that the bulk water content decreases while the adsorbed water content remains practically constant with increasing mechanical stress; hectorite adsorbs less water than Laponite at low hydraulic stress. The proportion of adsorbed water obtained by NMR confirms the TGA data. The interlamellar space and the equivalent water layers decrease with increasing mechanical stress and is always lower in hectorite than in Laponite. Hydromechanical effects on the water-Na-smectite system are in agreement with microtexture changes measured by porosimetry. Differences in the properties of the two clays can be attributed to the higher extension of the layers in hectorite compared with Laponite.

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