Effects of Cr Doping and Water Content on the Crystal Structure Transitions of Ba₂In₂O₅

Abstract

Temperature-dependent crystal structure alterations in the brownmillerite-type material Ba2In2O5 play a fundamental role in its applications: (i) photocatalytic CO2 conversion; (ii) oxygen transport membranes; and (iii) proton conduction. This is connected to a reversible uptake of up an equimolar amount of water. In this study, in situ X-ray and neutron diffraction were combined with Raman spectroscopy and solid-state nuclear magnetic resonance experiments to unravel the effects of Cr doping and water content on the crystal structure transitions of Ba2In2O5(H2O)x over a wide temperature range (10 K ≤ T ≤ 1573 K, x 2In2O5 resulted in severe structural changes and provides a powerful way to adjust its physical properties to the respective application.

Keywords

• X-ray diffraction
• neutron diffraction
• Raman spectroscopy
• crystal structure
• in situ studies
• brownmillerite