title: Topochemical Nitridation with Anion Vacancy-Assisted N(3-)/O(2-) Exchange.
abstract: We present how the introduction of anion vacancies in oxyhydrides enables a route to access new oxynitrides, by conducting ammonolysis of perovskite oxyhydride EuTiO3-xHx (x ∼ 0.18). At 400 °C, similar to our studies on BaTiO3-xHx, hydride lability enables a low temperature direct ammonolysis of EuTi(3.82+)O2.82H0.18, leading to the N(3-)/H(-)-exchanged product EuTi(4+)O2.82N0.12□0.06. When the ammonolysis temperature was increased up to 800 °C, we observed a further nitridation involving N(3-)/O(2-) exchange, yielding a fully oxidized Eu(3+)Ti(4+)O2N with the GdFeO3-type distortion (Pnma) as a metastable phase, instead of pyrochlore 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 EuTiO2.25N0.75, indicating that anion vacancies created during the initial nitridation process of EuTiO2.82H0.18 play a crucial role in promoting anion (N(3-)/O(2-)) exchange at high temperatures. Hence, by using (hydride-induced) anion-deficient precursors, we should be able to expand the accessible anion composition of perovskite oxynitrides.
authors: Riho
authors: R
authors: Mikita
authors: Tomoko
authors: T
authors: Aharen
authors: Takafumi
authors: T
authors: Yamamoto
authors: Fumitaka
authors: F
authors: Takeiri
authors: Tang
authors: T
authors: Ya
authors: Wataru
authors: W
authors: Yoshimune
authors: Koji
authors: K
authors: Fujita
authors: Suguru
authors: S
authors: Yoshida
authors: Katsuhisa
authors: K
authors: Tanaka
authors: Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors: Dmitry
authors: D
authors: Batuk
authors: Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.|Skoltech Center for Electrochemical Energy Storage, Skolkovo Institute of Science and Technology , 143026 Moscow, Russia.
authors: Artem M
authors: AM
authors: Abakumov
authors: Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, MD 20899, United States.
authors: Craig M
authors: CM
authors: Brown
authors: Yoji
authors: Y
authors: Kobayashi
authors: Hiroshi
authors: H
authors: Kageyama