Site Selectivity of Hydride in Early-Transition-Metal Ruddlesden-Popper Oxyhydrides

Hernandez, OJ and Geneste, G and Yajima, T and Kobayashi, Y and Okura, M and Aidzu, K and Tassel, C and Paofai, S and Swain, D and Ritter, C and Kageyama, H (2018) Site Selectivity of Hydride in Early-Transition-Metal Ruddlesden-Popper Oxyhydrides. In: Inorganic Chemistry, 57 (17). pp. 11058-11067.

PDF ino_che_57-17_11058-11067_2018.pdf - Published Version Restricted to Registered users only Download (2MB) | Request a copy

Abstract

Layered perovskite titanium oxyhydrides have been prepared by low-temperature topochemical CaH2 reduction from Ruddlesden-Popper Srn+1TinO3n+1 phases (n = 1, 2) and structurally characterized by combined synchrotron X-ray and neutron diffraction data refinements. In the single-layered Sr2TiO3.91(2)D0.14(1) material, hydride anions are statistically disordered with oxides on the apical site only, as opposed to known transition-metal oxyhydrides exhibiting a preferred occupation of the equatorial site. This unprecedented site selectivity of H- has been reproduced by periodic DFT+U calculations, emphasizing for the hydride defect a difference in formation energy of 0.24 eV between equatorial and apical sites. In terms of electronic structure, the model system Sr2TiO3.875H0.125 is found to be slightly metallic and the released electron remains mostly delocalized over several Ti atoms. On the other hand, hydride anions in the double-layered Sr3Ti2O6.20H0.12 material show a clear preference for the bridging apical site within the perovskite slabs, as confirmed by DFT calculations on the Sr3Ti2O6.875H0.125 model system. Finally, the influence of the B-site chemical nature on the hydride site selectivity for early 3d transition metals is theoretically explored in the single-layered system by substituting vanadium for titanium. The V3+ electronic polaron is suggested to play a role in stabilizing H- on the equatorial site in Sr2VO4-xHx for x = 0.125.

Item Type:	Journal Article
Publication:	Inorganic Chemistry
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	05 Aug 2022 10:51
Last Modified:	05 Aug 2022 10:51
URI:	https://eprints.iisc.ac.in/id/eprint/75384

Actions (login required)

View Item