Formation of Ba 3 Nb 0.75 Mn 2.25 O 9 -6H during thermo-chemical reduction of Ba 4 NbMn 3 O 12 -12R.

Autor: Strange NA; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator, Laboratory, Menlo Park, CA 94025, USA., Bell RT; National Renewable Energy Laboratory, Golden, CO 80401, USA., Park JE; Sandia National Laboratories, Albuquerque, NM 87185, USA., Stone KH; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator, Laboratory, Menlo Park, CA 94025, USA., Coker EN; Sandia National Laboratories, Albuquerque, NM 87185, USA., Ginley DS; National Renewable Energy Laboratory, Golden, CO 80401, USA.
Jazyk: angličtina
Zdroj: Acta crystallographica. Section E, Crystallographic communications [Acta Crystallogr E Crystallogr Commun] 2023 Apr 14; Vol. 79 (Pt 5), pp. 469-473. Date of Electronic Publication: 2023 Apr 14 (Print Publication: 2023).
DOI: 10.1107/S2056989023003213
Abstrakt: The resurgence of inter-est in hydrogen-related technologies has stimulated new studies aimed at advancing lesser-developed water-splitting processes, such as solar thermochemical hydrogen production (STCH). Progress in STCH has been largely hindered by a lack of new materials able to efficiently split water at a rate comparable to ceria under identical experimental conditions. BaCe 0.25 Mn 0.75 O 3 (BCM) recently demonstrated enhanced hydrogen production over ceria and has the potential to further our understanding of two-step thermochemical cycles. A significant feature of the 12R hexa-gonal perovskite structure of BCM is the tendency to, in part, form a 6H polytype at high temperatures and reducing environments ( i.e. , during the first step of the thermochemical cycle), which may serve to mitigate degradation of the complex oxide. An analogous compound, namely BaNb 0.25 Mn 0.75 O 3 (BNM) with a 12R structure was synthesized and displays nearly complete conversion to the 6H structure under identical reaction conditions as BCM. The structure of the BNM-6H polytype was determined from Rietveld refinement of synchrotron powder X-ray diffraction data and is presented within the context of the previously established BCM-6H structure.
(© Strange et al. 2023.)
Databáze: MEDLINE
Externí odkaz: