New data on protonation and hydration of perovskite-type layered oxide KCa2Nb3O10
Protonation and hydration processes of layered perovskite-like oxide KCa2Nb3O10 during the reaction with nitric acid solutions with different concentrations were studied by means of TG, STA + MS, XRD, SEM, EDX and ICP methods. It was found that despite the absence of significant changes in crystal structure, treatment of KCa2Nb3O10 with water leads to the partial substitution of K+ with H+ (about 15% exchange), while a number of new hydrated protonated phases HxK1−xCa2Nb3O10·yH2O with higher exchange (50–90%) may be obtained using moderate acid concentrations (0.1–3 M HNO3) varying reaction time. It was shown that production of the fully protonated form requires the minimum 3 M concentration of the acid and 24 h reaction time.
KeywordsThermogravimetry Layered perovskite-type oxides Niobates Protonation Hydration
This work was supported by the Russian Science Foundation (Grant No. 19-13-00184). Authors also are grateful to Saint Petersburg State University Research Park. TG and DSC studies were carried out in Center of Thermal Analysis and Calorimetry, XRD study was carried out in Research Centre for X-ray Diffraction Studies, SEM images were obtained in Interdisciplinary Resource Center for Nanotechnology, ICP study was carried out in Center for chemical analysis and materials research.
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The authors declare that they have no conflict of interest.
- 5.Manonmani M, Jaikumar V, Gokul Raj S, Ramesh Kumar G. Crystallization, non-isothermal kinetics and structural analysis of nanocrystalline multiferroic bismuth ferrite (BiFeO3) synthesized by combustion method. J Therm Anal Calorim. 2019. https://doi.org/10.1007/s10973-019-08251-3.CrossRefGoogle Scholar
- 10.Kim SY, Oh J, Park J, Byeon S. Structure of new layered oxides MII 0.5LaTiO4 (M = Co, Cu, and Zn) synthesized by the ion-exchange reaction. Society. 2002;4:1643–8.Google Scholar
- 32.Domen K, Yoshimura J, Sekine T, Kondo J, Tanaka A, Maruya K, et al. A novel series of photocatalysts with an ion-exchangeable layered structure of niobate. Catal Lett. 1993;75:2159–62.Google Scholar