18649-05-3Relevant articles and documents
Direct electrochemical synthesis of oxygenates from ethane using phosphate-based electrolysis cells
Fujiwara, Naoya,Honda, Yusuke,Kikuchi, Ryuji,Kobayashi, Yasukazu,Oyama, Shigeo Ted,Tada, Shohei
, p. 11199 - 11202 (2020)
Ethane was converted directly to acetaldehyde and ethanol by partial oxidation at 220 °C and ambient pressure using an electrolysis cell with a proton-conducting electrolyte, CsH2PO4/SiP2O7, and Pt/C electrodes. The ethane conversion and the selectivity to the products increased with the voltage applied to the cell. It was found that O species generated by water electrolysis functioned as a favorable oxidant for partial oxidation of ethane on the Pt/C anode at intermediate temperatures. The production rates of acetaldehyde and ethanol recorded in this study were significantly higher than those in preceding reports.
TEMPERATURE VARIATIONS OF OPTICAL INDICATRIX AND BIREFRINGENCE IN FERROELECTRIC CsH2PO4.
Ushio
, p. 3242 - 3249 (1984)
The principal values and the rotation angle of the optical indicatrix and the optical birefringence of CsH//2PO//4 have been measured at 589 nm as a function of temperature both in the paraelectric and the ferroelectric phases. Rotation of the optical indicatrix with temperature about the b-axis is within 1 degree between 100 K and 300 K. The spontaneous birefringence determined for (010) plate by the usual procedure reaches a maximum at about 15 K below T//c, then becomes negative with decreasing temperature. Similar behavior is found for (100) plate. It is found that these anomalous behaviors of the spontaneous birefringence are caused by the similar anomalous behavior in the spontaneous strain through the elastooptic coupling.
An oxide ion and proton co-ion conducting Sn0.9In 0.1P2 O7 electrolyte for intermediate- temperature fuel cells
Chen, Xilin,Wang, Chunsheng,Payzant, E. Andrew,Xia, Changrong,Chu, Deryn
, p. B1264-B1269 (2008)
The ionic conductivity of Sn0.9In0.1P2 O7 ceramic was investigated under various atmospheres within the temperature range of 130-230°C. Similar to mixed-conductive perovskite oxides at high temperatures (such as SrCe0.95Yb0.05 O 3-α, La0.9 Sr0.1Ga0.8 Mg 0.2 O3-α at 600-1000°C), Sn0.9In 0.1P2 O7 can conduct both protons and oxide ions at low temperatures (130-230°C). The conductivity of Sn 0.9In0.1P2 O7 reaches 0.019 Scm at 200°C in wet nitrogen. Its transport numbers determined by steam concentration cells are around 0.76 for a proton and 0.12 for an oxide ion. The performance of direct methanol fuel cells at 170°C using mixed-ion conductive Sn0.9In0.1P2 O7 electrolyte is higher than that at 235°C using pure proton conductive CsH2PO4 electrolyte. This is attributed to direct oxidation of CO at the anode by the oxide ions generated at the cathode and moved through the Sn0.9In0.1P2 O7 electrolyte.
Thermal analysis of CsH2PO4 nanoparticles using surfactants CTAB and F-68
Hosseini,Mohamad,KaHum,Wan Daud
, p. 197 - 202 (2010)
A study concerned to thermogravimetric analysis is performed in cesium dihydrogen phosphate (CsH2PO4) that was synthesized, using cetyltrimethylammonium-bromide (CTAB), polyoxyethylene-polyoxypropylene (F-68) and mixture of (F-68:CTAB) with two mole ratio 0.06 and 0.12 as surfactant. The dehydration behavior of particles was studied using thermal gravimetric analysis and differential scanning calorimetric. Subsequently, the experimental results indicated that the first dehydration temperature in the range of 237-239 °Cupon heating, the second peaks occur at temperature range 290-295 °C and overlapping in the thermogravimetric events is observed. The mass loss values are obtained in the range of 6.62-6.97 wt% that is less than reported theoretical value 7.8 wt%. These values show well compatibility of reaction CsH2PO4 to Cs2H2P2O 7 with 3.92 wt% whereas mass loss value of CsH2PO 4 to CsPO3 is less than theoretical value 7.8 wt%. The activation energy of two steps dehydration are calculated using Kissinger equation for the samples synthesized via CTAB and (F-68) with minimum value mass loss 6.62% and maximum value mass loss 6.97%, respectively. The calculation results reveal that the reaction rate in the first step (CsH2PO 4 → Cs2H2P2O7) is faster than the second step (CsH 2PO4 → CsPO3). The weight loss values of the samples demonstrate that existence of CTAB can be considered as effective factor which prevents more weight loss during the dehydration process. Akademiai Kiado, Budapest, Hungary 2009.
Effect of silica on the thermal behaviour and ionic conductivity of mixed salt solid acid composites
Mohammad, Norsyahida,Mohamad, Abu Bakar,Kadhum, Abdul Amir H.,Loh, Kee Shyuan
, p. 896 - 902 (2017)
The effect of adding silica (SiO2) to a mixed-salt solid acid composite, CsH2PO4/NaH2PO4, was studied via conductivity measurements, thermal analyses and X-ray diffraction. The conductivity value of the composites ranged from 1.1?×?10?4?S?cm?1to 7.6?×?10?3?S?cm?1for temperatures from 210?°C to 250?°C, respectively. Adding NaH2PO4to the composite reduced the conductivity value at 230?°C due to the decomposition of NaH2PO4, which initiated at 210?°C. Dehydration of CsH2PO4was evident at 230?°C and 270?°C, while the superprotonic phase transition was not observed. Dehydration was detected for NaH2PO4at temperatures above 210?°C, but a thermally stable composite was produced by mixing it with CsH2PO4and SiO2. An X-ray diffraction analysis confirmed the existence of solid acid solutions for the composites consisting of NaH2PO4:CsH2PO4and SiO2:CsH2PO4in molar ratios of 1:10 to 3:10. The presence of SiO2partially obstructed the dehydration of the composite, as the diffraction intensity of the dehydration by-product Cs2H2P2O7decreased at the end of the thermal treatment.
Electrical and thermodynamic properties of Cs0.97 Rb 0.03H2PO4
Lavrova,Martsinkevich,Ponomareva
, p. 795 - 801 (2009)
The transport properties of Cs0.97Rb0.03H 2PO4 have been studied using polycrystalline samples and single crystals. The mixed salt is isostructural with cesium dihydrogen phosphate and has slightly smaller unitc
POLARIZED INFRARED AND RAMAN SPECTRA OF MONOCLINIC CsH2PO4 SINGLE CRYSTAL AND ITS DEUTERATED HOMOLOGUE CsD2PO4 Part 1. Hydrogen bond study
Videnova-Adrabinska, V.,Baran, J.
, p. 1 - 14 (1987)
The object of clearly distinguishing the stretching modes originating from the short (ν2) and long (ν1) hydrogen bond in CsH2PO4 has been achieved by recording polarized spectra on the (010) plane using different orientations of the electric vector component.Band parameters of the ν1 stretching mode are taken as a function of the temperature.Calculations of the orientation of the transition dipole moments for the six proton vibrations (ν1, δ1, γ1 and ν2, δ2, γ2) are performed and correlated with the experimental results.
CRITICAL SLOWING-DOWN AND STATIC DIELECTRIC CONSTANT OF MONOCLINIC RbD2PO4.
Komukae,Makita
, p. 4359 - 4369 (1985)
The real and imaginary parts of the complex dielectric constant along the b axis of monoclinic RbD//2PO//4 were measured in a frequency range between 10**6 Hz and 10**9 Hz. It was found that RbD//2PO//4 shows dielectric critical slowing-down near the ferrielectric phase transition point. In addition, the static dielectric constants ( epsilon //0) of RbD//2PO//4 and the partially deuterated crystal Rb(D//0//. //3H//0//. //7)//2PO//4 were also measured at 10**4 Hz. A theoretical expression of epsilon //0 for a ferrielectric phase transition was obtained on the basis of the quasi-one-dimensional Ising model with assumed two sublattices. The remarkable deviations of epsilon //0 from the Curie-Weiss law observed in these crystals were analyzed successfully by the present theoretical result and the experimental results were discussed.
X-ray structural study of ferroelectric cesium dihydrogen phosphate at room temperature
Matsunaga, Hironori,Itoh, Kazuyuki,Nakamura, Eiji
, p. 2011 - 2014 (1980)
The atomic coordinates and the anisotropic thermal parameters of CsH 2PO4 crystal in the paraelectric phase have been obtained using three-dimensional X-ray intensity data collected by a four-circle automatic diffractometer at room temperature. The structure is refined to R=0.029 for 780 independent reflections. Two types of hydrogen bonds are clearly distinguished in the electron density maps which display distributions corresponding to order and disorder of protons, respectively.
Intermediate-temperature fuel cell employing CsH2PO 4/SiP2O7-based composite electrolytes
Matsui, Toshiaki,Kukino, Tomokazu,Kikuchi, Ryuji,Eguchi, Koichi
, p. A339-A342 (2006)
The proton-conductive electrolytes based on CsH2 PO4 SiP2 O7 composites with various molar ratios were synthesized, and their structural and electrochemical properties were investigated at intermediate temperatures. The interfacial chemical reaction betwe
