scholarly journals How do the doping concentrations of N and B in graphene modify the water adsorption?

RSC Advances ◽  
2021 ◽  
Vol 11 (32) ◽  
pp. 19560-19568
Author(s):  
Thi Tan Pham ◽  
Thanh Ngoc Pham ◽  
Viorel Chihaia ◽  
Quang Anh Vu ◽  
Thuat T. Trinh ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Water Adsorption ◽  
Geometrical Structure ◽  
Adsorbed Water ◽  
Doping Content ◽  
B Doping

N and B doping content in graphene alters the microscopic geometrical structure and electronic properties of adsorbed water.

scholarly journals Calorimetric and Spectroscopic Studies of Water Adsorption onto Alkaline Earth Fluorides

2005 ◽  
Vol 23 (6) ◽  
pp. 425-436
Author(s):  
Toshinori Mori ◽  
Yasushige Kuroda ◽  
Ryotaro Kumashiro ◽  
Koji Hirata ◽  
Hidehiro Toyota ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Water Adsorption ◽  
Adsorbed Water ◽  
Spectroscopic Studies ◽  
Water Molecules ◽  
Earth Fluoride ◽  
Alkaline Earth Fluoride ◽  
Pretreatment Temperature ◽  
Argon Adsorption ◽  
Ir Bands

Interactions between the surfaces of alkaline earth fluorides (CaF2, SrF2 and BaF2) and water molecules were investigated by calorimetric and spectroscopic methods. The exposed surfaces of the alkaline earth fluoride samples, with which the (100) crystalline plane is mainly associated, were found to be fully covered with strongly adsorbed water molecules, resulting in characteristic IR bands at 3684, 2561, 1947 and 1000 cm−1, respectively. This surface was homogeneous towards further water adsorption. The strongly adsorbed water molecules were almost completely desorbed from the surface on evacuating the sample up to 473 K. The heat of immersion in water also increased with increasing pretreatment temperature; this may be attributed to surface rehydration of the alkaline earth fluorides. The state of the surface changed drastically as the pretreatment temperature was increased and stabilized towards incoming water molecules. Thus, the surface formed after evacuation at temperatures greater than 473 K was resistant to hydration even after immersion in water at room temperature. This surface was relatively heterogeneous towards water adsorption, although it behaved homogeneously towards argon adsorption. These facts indicate that strongly adsorbed water molecules appear to be somewhat specific towards the adsorption of further incoming water molecules. The adsorption properties of the (100) plane of alkaline earth fluorides towards water and argon molecules depend strongly on both the electrostatic field strength and the extent of rehydration of the alkaline earth fluoride surface.

Free Energy and Electronic Properties of Water Adsorption on the SnO2(110) Surface

Langmuir ◽  
2013 ◽  
Vol 29 (18) ◽  
pp. 5487-5499 ◽  
Author(s):  
Gianluca Santarossa ◽  
Konstanze Hahn ◽  
Alfons Baiker
Keyword(s):  
Free Energy ◽  
Electronic Properties ◽  
Water Adsorption

Changes in Water Adsorption Desorption Isotherms of Cement Mortars Caused by Carbonation Coupled with Humidification-Drying Cycles

2014 ◽  
Vol 989-994 ◽  
pp. 705-709
Author(s):  
Tung Pham Son
Keyword(s):  
Water Adsorption ◽  
Coupling Effect ◽  
Adsorbed Water ◽  
Water Vapor Adsorption ◽  
Adsorption Method ◽  
Cement Mortars ◽  
Pore Size Distributions ◽  
Low Humidity ◽  
Desorption Isotherms ◽  
Adsorption Desorption

The objective of this work was to examine the influence of carbonation on the water vapor adsorption desorption isotherms of cement materials. Two types of Portland mortars, which were CEM I and CEM II, were carbonated at 20°C, 65% relative humidity and 20% of CO2concentration. The pore size distributions were determined from the water adsorption method. We also studied the coupling effect between carbonation and humidification-drying cycles. The results showed a reduction in microporosity and a small increase in the mesoporosity. The pores clogging due to formation of calcium carbonate was highlighted by the reduction of the quantity of adsorbed water and the decrease in the hysteresis isotherms. The results of this study also indicated that the humidification-drying cycles coincide only from the second cycle because of a difficult evacuation of water during desorption, even at low humidity.

Photoelectrochemical and opto-electronic properties tuning of ZnO films: Effect of Cu doping content

2017 ◽  
Vol 722 ◽  
pp. 313-320 ◽  
Author(s):  
M. Salem ◽  
I. Massoudi ◽  
S. Akir ◽  
Y. Litaiem ◽  
M. Gaidi ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Zno Films ◽  
Doping Content ◽  
Cu Doping

Molecular Orbital Modeling of Water Adsorption on a Tetrasiloxane Ring

1990 ◽  
Vol 180 ◽  
Author(s):  
J. K. West ◽  
S. Wallace
Keyword(s):  
Water Molecule ◽  
Molecular Orbital ◽  
Water Adsorption ◽  
Adsorbed Water ◽  
Metal Alkoxide ◽  
Sioh Group ◽  
Vibrational Overtone ◽  
Neglect Of Differential Overlap ◽  
Mo Theory ◽  
Hydrogen Bonded

ABSTRACTA water molecule hydrogen bonded to a surface SiOH group produces an IR vibrational transmission peak (ν3) at 2.82 μm. Water was adsorbed into the pores of a metal alkoxide derived silica gel monolith, and the increase in the wavelength of the first vibrational overtone (2ν3) of this peak was measured as a function of the adsorbed water content W (g H2O/g SiO2). The peak shifted from 1.390 to 1.420 μm as W increased by 0.14 g/g. Intermediate Neglect of Differential Overlap (INDO) Molecular Orbital (MO) theory was used to model this process. The effect of a H2O molecule, hydrogen bonded to a hydroxylated tetrasiloxane ring, on the structure of the ring and the water molecule was investigated. The bond length of the O-H group H-bonded to the water molecule increased, as expected from the increase in wavelength of the 2ν3 IR peak.

scholarly journals Synthesis, structure and water sorption in Zr metal-organic frameworks

2014 ◽  
Vol 70 (a1) ◽  
pp. C1240-C1240
Author(s):  
Felipe Gándara ◽  
Hiroyasu Furukawa ◽  
Zhang Yue-Biao ◽  
Juncong Jiang ◽  
Wendy Queen ◽  
...  
Keyword(s):  
Water Adsorption ◽  
Metal Organic Frameworks ◽  
Adsorbed Water ◽  
Neutron Diffraction Study ◽  
Water Molecules ◽  
Remote Areas ◽  
Adsorption Sites ◽  
Thermal Batteries ◽  
Secondary Building Units ◽  
Metal Organic

Metal-organic frameworks (MOFs) based on zirconium secondary building units (SBUs) have proven to have great thermal and chemical stability,[1,2] which make them ideal for their use in different applications. We have prepared a series of six new MOFs made from the Zr6O4(OH)4(-CO2)nsecondary building units (n = 6, 8, 10, or 12) and variously shaped carboxyl organic linkers to make extended porous frameworks, with the aim of studying their performance as water adsorbents. Thus, we have evaluated the water adsorption properties of these new MOFs and other reported porous materials to identify the compounds with the most promising materials for use in applications such as thermal batteries or delivery of drinking water in remote areas. An X-ray single-crystal and a powder neutron diffraction study reveal the position of the water adsorption sites in one of the best performing materials, and highlight the importance of the intermolecular interactions between adsorbed water molecules within the pores.

scholarly journals Effect of Water Adsorption on Cation-Surface Interaction Energy in the Na-Mordenite of 5.5 : 1 Si/Al Ratio

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Sekou Diaby
Keyword(s):  
Activation Energy ◽  
Surface Properties ◽  
Surface Potential ◽  
Water Adsorption ◽  
Adsorbed Water ◽  
Material Surface ◽  
Water Molecules ◽  
Zeolite Surface ◽  
Inner Surface ◽  
Insight Into

The mobility of the Na+cations localized at the inner surface of the studied mordenite zeolite depends on the material surface properties. In this work, we show that the activation energy,ΔEhop, relating to the Na+cation hopping displacement is associated to the surface potential and therefore can be used to get a better insight into the zeolite surface properties. Indeed, when molecules as water are adsorbed at the surface, they modify the surface potential energy and hence influence the value ofΔEhop. If the adsorbed molecules are polar they directly interact with the cations which become more mobile. The more theΔEhopvalue is, the less the amount of adsorbed water molecules is. Alterations of theΔEhopvalue with respect to the amount of adsorbed water molecules are interpreted using the Dubinin model which is based on simple adsorption principle.

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.

Water adsorption onto Y and V sites at the surface of the YVO4 photocatalyst and related electronic properties

2009 ◽  
Vol 131 (3) ◽  
pp. 034701 ◽  
Author(s):  
Mitsutake Oshikiri ◽  
Mauro Boero ◽  
Akiyuki Matsushita ◽  
Jinhua Ye
Keyword(s):  
Electronic Properties ◽  
Water Adsorption
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