Topochemical Nitridation with Anion Vacancy-Assisted N3-/O2- Exchange

Published

March 9, 2016

Author(s)

Riho Mikita, Tomoko Aharen, Takafumi Yamamoto, Fumitaka Takeiri, Tang Ya, Wataru Yoshimune, Koji Fujita, Suguru Yoshida, Katsuhisa Tanaka, Dmitry Batuk, Artem M. Abakumov, Craig Brown, Yoji Kobayashi, Hiroshi Kageyama

Abstract

We present how the introduction of anion vacancies in oxyhydrides enables a route to access new oxynitrides, by conducting ammonolysis of perovskite oxyhydride EuTiO_3-xH_x (x0.18). At 400 °C, similar to our studies on BaTiO_3-xH_x, hydride lability enables a low temperature direct ammonolysis of EuTi^3.82+O_2.82H_0.18, leading to the N^{3_/H-exchanged product EuTi}u4+^O_2.82N_0.12square}_0.06. When the ammonolysis temperature is increased up to 800 °C, we observed a further nitridation involving N^3-/O^2- exchange, yielding a fully oxidized Eu³⁺Ti⁴⁺O₂N with GdFeO₃-type distortion(Pnma) as a metastable phase, instead of pyrochlore structure structure. Interestingly, the same reactions using the oxide EuTiO₃ proceeded through a 1:1 exchange of N^3- with O^2- only above 600 °C and resulted in incomplete nitridation to EuTiO_2.25Nd0.75^, indicating that anion vacancies created during the initial nitridation process of EuTiO_2.82H_0.18 play a crucial role in promoting anion (N^3-/Ou2-) exchange at high temperatures. Hence, by using hydride-induced anion-deficient prefursors, we should be able to expand the accessible anion composition of perovskite oxynitrides.

Citation

Journal of the American Chemical Society

Volume

138

Issue

9

Pub Type

Journals

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Keywords

Oxynitride, perovskite, structure, diffraction

Citation

Mikita, R. , Aharen, T. , Yamamoto, T. , Takeiri, F. , Ya, T. , Yoshimune, W. , Fujita, K. , Yoshida, S. , Tanaka, K. , Batuk, D. , Abakumov, A. , Brown, C. , Kobayashi, Y. and Kageyama, H. (2016), Topochemical Nitridation with Anion Vacancy-Assisted N^3-/O^2- Exchange, Journal of the American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920131 (Accessed September 12, 2024)