Phase separation and crystallization in sodium lanthanum phosphate glasses induced by electrochemical substitution of sodium ions with protons

2015 ◽  
Vol 17 (35) ◽  
pp. 22855-22861 ◽  
Author(s):  
Keiga Kawaguchi ◽  
Takuya Yamaguchi ◽  
Takahisa Omata ◽  
Toshiharu Yamashita ◽  
Hiroshi Kawazoe ◽  
...  

Phase separation and crystallization forming H3PO4 occurred in sodium lanthanum phosphate glasses after electrochemical substitution of sodium ions with protons, although the glass exhibited significant proton conductivity.

RSC Advances ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 355-364
Author(s):  
My V. Nguyen ◽  
Thang B. Phan ◽  
Man V. Tran ◽  
Tuyet A. T. Nguyen ◽  
Hung N. Nguyen

A series of N-heterocyclic⊂VNU-23 materials have been prepared via the impregnation procedure of N-heterocyclic molecules into VNU-23.


2000 ◽  
Author(s):  
Richard K. Brow ◽  
Ezz Metwalli ◽  
David L. Sidebottom

1996 ◽  
Vol 212 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Vladimir M. Syutkin ◽  
Vladimir A. Tolkatchev

2016 ◽  
Vol 55 (4) ◽  
pp. 047102 ◽  
Author(s):  
Jan Šulc ◽  
Richard Švejkar ◽  
Helena Jelínková ◽  
Karel Nejezchleb ◽  
Karel Nitsch ◽  
...  

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 240
Author(s):  
Mallaurie Foucaud ◽  
Sanja Renka ◽  
Teodoro Klaser ◽  
Jasminka Popović ◽  
Željko Skoko ◽  
...  

A series of glass-ceramics were prepared by heat-treatments of 40Na2O-30MoO3-30P2O5 (in mol%) glass in a temperature range from 380 (Tg) to 490 °C (Tc) and for 1–24 h. The prepared glass-ceramics contain from 2 to 25 wt.% of crystalline NaMoO2PO4. The sodium-ion conductivity in these materials decreases up to one order of magnitude with an increase in the degree of crystallization due to the immobilization of sodium ions in crystalline NaMoO2PO4. The transport of sodium ions in these materials occurs primarily through the dominant continuous glassy phase, and it is weakly affected by the sporadically distributed crystalline grains. However, the prepared glass-ceramics exhibit high proton conductivity in a humid atmosphere and remarkable humidity-sensing properties; this could be related to crystalline NaMoO2PO4, which provides sites for water adsorption. The glass-ceramic prepared at 450 °C for 24 h shows the best humidity-sensing performance among all samples, showing an increase in proton conductivity for more than seven orders of magnitude with the increase in relative humidity from 0% to 95%. Under a highly humid atmosphere (95% relative humidity and 25 °C), the proton conductivity of this glass-ceramic reaches 5.2 × 10−3 (Ω cm)−1. Moreover, the electrical response of these materials on the change in the relative humidity is linear and reversible in the entire range of the relative humidity, which indicates that they are novel promising candidates for application as humidity sensors.


1998 ◽  
Vol 547 ◽  
Author(s):  
S. Prabakar ◽  
J.M. Egan ◽  
R.M. Wenslow ◽  
K.T. Mueller

AbstractThe correlation between 23Na and 31P nuclei in alkali phosphates has been investigated by cross-polarization MAS NMR spectroscopy. Connectivity between sodium ions with various phosphorus tetrahedra has been demonstrated in a variety of crystalline-and amorphous alkali phosphates. CPMAS NMR experiments were also performed on sodium aluminophosphate glasses from both quadrupolar nuclei (23Na and 27Al) to the phosphorus nuclei to establish connectivity of sodium and phosphorus as well as aluminum and phosphorus nuclei in these systems.


2010 ◽  
Vol 118 (1384) ◽  
pp. 1131-1134 ◽  
Author(s):  
Shin-ichi MINAMIYAMA ◽  
Yusuke DAIKO ◽  
Atsushi MINESHIGE ◽  
Masafumi KOBUNE ◽  
Tetsuo YAZAWA

2002 ◽  
Vol 756 ◽  
Author(s):  
D. Carrière ◽  
M. Moreau ◽  
K. Lahlil ◽  
P. Barboux ◽  
J.-P. Boilot

ABSTRACTColloidal 60 nm ZrO2 particles have been treated with aqueous solutions of phosphoric acid and sulphophenyl-phosphonic acid (SPPA). This leads to the covalent bonding of P-OH and C6H4-SO3H acid groups onto the surface of the particles. The resulting acidity yields a significant proton conductivity at the surface of the particles.The proton conductivity of the ZrO2-H3PO4 system is quite stable against a change of relative humidity and temperature. However, it remains limited by the low acidity of the POH group. On the contrary, the proton conductivity of the ZrO2-SPPA system is almost two orders of magnitude higher at high relative humidities due to the high acidity of the C6H4-SO3H group (1.10-3 S.cm-1 in the same conditions). But, it is much more sensitive to changes in relative humidity.A mixed grafting of both H3PO4 and SPPA onto the zirconia particles allows to obtain a conductivity as high as in the SPPA case whereas it remains stable with humidity and temperature as for the phosphoric acid. This probably indicates that the conductivity arises from ionization of sulphonic acid but that the weaker phosphoric acid groups contribute to the conduction mechanism.


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