Tailoring the photocatalytic activity of layered perovskites by opening the interlayer vacancy via ion-exchange reactions

CrystEngComm ◽  
2015 ◽  
Vol 17 (45) ◽  
pp. 8703-8709 ◽  
Author(s):  
Yingqi Wang ◽  
Xiaofang Lai ◽  
Xujie Lü ◽  
Yanting Li ◽  
Qinglong Liu ◽  
...  

The photocatalytic activity of the layered perovskite K2La2Ti3O10 was regulated by an ion-exchange reaction with a series of cations – Ca2+, Sr2+, and Ba2+. The underlying mechanism of the improved performance and an effective model for designing the photocatalyst were discussed.

2006 ◽  
Vol 114 (1334) ◽  
pp. 861-865 ◽  
Author(s):  
Sachi TAKEZAWA ◽  
Takashi TERANISHI ◽  
Hironori ISHIKAWA ◽  
Toshiaki TOKUMITSU ◽  
Kenji TODA ◽  
...  

NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850012 ◽  
Author(s):  
Na Cao ◽  
Huiling Du ◽  
Jun Liu ◽  
Lianli Wang

Bi4Ti3O[Formula: see text]/Bi2S3 heterostructures with enhanced visible light photocatalytic activity are successfully synthesized via a two-step synthesis route based on a sol–gel hydrothermal method and a subsequent hydrothermal-ion exchange reaction technique. The structures, composition, morphologies and light absorption capability of Bi4Ti3O[Formula: see text]/Bi2S3 heterostructures are verified by XRD, XPS, SEM, TEM and UV-Vis diffuse reflectance spectra, respectively. Results indicated that Bi2S3 nanorods are grown on the surface of the spherical structure assembled by criss-cross nanosheets of Bi4Ti3O[Formula: see text] after ion exchange reaction. The photocatalytic tests reveal that the Bi4Ti3O[Formula: see text]/Bi2S3 heterostructures showed much higher photocatalytic activity than pure Bi4Ti3O[Formula: see text] or Bi2S3. The tight interconnection between the two semiconductors will facilitate the photoinduced carriers’ separation. Owing to the easy preparation and excellent property, the obtained Bi4Ti3O[Formula: see text]/Bi2S3 heterostructures may be promising photocatalysts for practical application.


Author(s):  
Pravin U. Singare ◽  
Akmal L. Khan Mohammed ◽  
N.N. Dixit

The present paper deals with the thermodynamic of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223. It was observed that with rise in temperature the equilibrium constants K values for H+/K+ uni-univalet ion exchange reaction increases from 0.01710 to 0.02374. Similarly for H+/Ca2+ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in K values with rise in temperature for both the reactions indicates its endothermic nature having the enthalpy change values of 22.72 and 38.92 kJ/ mol respectively. The technique used here can be extended further to standardise the process parameters in order to bring about the efficient separation of the desired ionic species from the solution


Author(s):  
P.U. Singare ◽  
A.N. Patange

The thermodynamic approach was applied to predict the trend selectivity of industrial grade anion exchange resin Auchlite A-378 in chloride form towards iodide and bromide ions in the solution. The study was conducted by performing the Clˉ/Iˉ and Clˉ/Brˉ uni-univalent ion exchange reactions under gradually increasing temperature conditions. The thermodynamic equilibrium constants K values were used to calculate the enthalpies of the two uni-univalent ion exchange reactions. It was observed that the K values for Clˉ/Iˉ ion exchange reaction were higher than Clˉ/Brˉ exchange reaction under identical experimental conditions. Also the enthalpy values for the two uni-univalent ion exchange reactions were calculated as -39.51 and -18.38 kJ/mol respectively. The high K and low enthalpy values obtained for Clˉ/Iˉ ion exchange reaction is responsible for higher selectivity of the resin towards iodide ions as compared to that towards bromide ions, when both the ions are present in the same solution.


Author(s):  
P.U. Singare ◽  
A.N. Patange

The paper deals with predicting the iodide ion selectivity of nuclear and non-nuclear grade anion exchange resins. The ionic selectivity prediction was made on the basis of thermodynamic data of Clˉ/I ˉ ion exchange reaction. It was observed that with rise in temperature from 30.0°C to 45.0 °C, the equilibrium constant (K) values were observed to decreases from 59.77x10-2 to 23.77x10-2 for Auchlite ARA-9366 resins and from 9.01x10-2 to 4.05x10-2 for Auchlite A-378 resins. The decrease in K values with rise in temperature, indicate exothermic ion exchange reactions having enthalpy values of -47.87 and -39.51 kJ/mol respectively. The high K and low enthalpy values obtained for Auchlite ARA-9366 resins indicate their greater selectivity for the iodide ions in the solution as compared to Auchlite A-378 resins, when both the resins are present in chloride form.


2006 ◽  
Vol 301 ◽  
pp. 227-230
Author(s):  
Kenji Toda ◽  
Hiroki Sato ◽  
Akira Sugawara ◽  
Saori Tokuoka ◽  
Kazuyoshi Uematsu ◽  
...  

We present a new method for soft chemical synthesis of perovskite materials. Perovskite K1-xLixNbO3 powders are produced by an ion-exchange reaction of layered perovskite precursor, K2NbO3F, with lithium chloride in water at room temperature. X-ray diffraction and X-ray fluorescent spectroscopic studies show that a mechanism of the ion-exchange reaction is a self-assembly between the perovskite nanosheets in aqueous solution.


2000 ◽  
Vol 2 (19) ◽  
pp. 4461-4464 ◽  
Author(s):  
Hiroyuki Takahashi ◽  
Masato Kakihana ◽  
Yohichi Yamashita ◽  
Kiyohide Yoshida ◽  
Sigeru Ikeda ◽  
...  

Author(s):  
Pravin U. Singare ◽  
Akmal L. Khan Mohammed ◽  
N.N. Dixit

The present paper deals with the ion exchange equilibrium studies of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223 in H+ form towards Na+ and Ca2+ ions in the solution. It was observed that with rise in temperature the equilibrium constants K values for H+/Na+ uni-univalet ion exchange reaction increases from 0.01389 to 0.01855. Similarly for H+/Ca2+ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 38.92 kJ/ mol respectively.


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