Ab initio study of atomic and electronic structure of promising Ba₄XMn₃O₁₂ (X = Nb, Ce, Pr) oxides for solar thermochemical hydrogen production / Anuj Goyal and Stephan Lany.

Format:

Book

Government document

Author/Creator:

Goyal, Anuj, author.

Lany, Stephan, author.

Contributor:

National Renewable Energy Laboratory (U.S.), issuing body.

Series:

NREL/PR ; 5K00-81060.

NREL/PR ; 5K00-81060

Language:

English

Subjects (All):

Thermochemistry.

Magnetic structure.

Physical Description:

1 online resource (16 pages, 1 unnumbered page) : color illustrations.

Other Title:

Ab initio study of atomic and electronic structure of promising Barium 4 X Manganese 3 Oxygen 12 (X = Niobium, Cerium, Praseodymium) oxides for solar thermochemical hydrogen production

Place of Publication:

[Golden, Colo.] : National Renewable Energy Laboratory, 2021.

Summary:

The two-step metal oxide water-splitting cycle is one of the most viable approach for Solar Thermochemical Hydrogen (STCH) production. Challenges exist in finding suitable oxides that can satisfy thermodynamics of the STCH redox cycle under viable range of temperatures and partial pressures. Recently, BXM family members, i.e., Ba4NbMn3O12 (BNM), Ba4CeMn3O12 (BCM), Ba4PrMn3O12 (BPM) are discovered to exhibit promising STCH performance. However, the magnetic degrees of freedom of their experimental crystal structures is not characterized, and only hypothetical models exist for their electronic structure. We performed Monte-Carlo sampling for the magnetic spin arrangement of Mn atoms to provide explicit atomic structure models for their ground state 12R polytype and determined the most stable spin configuration for each member after structure relaxation using density functional theory (DFT) calculations. We also elucidate the most stable charge configuration (Mn3+/Mn4+ arrangement) for BNM among the existing hypothesis in literature. We investigate these strongly correlated oxides using different levels of theory (DFT+U, Hybrid-DFT) to develop better understanding of their electronic structure. These calculations allowed us to develop a model based on molecular orbital interactions that help explain the observed changes in their experimental x-ray spectroscopy measurements. Thereby, help link differences in electronic structure of BXM family members to their varying water-splitting behavior. These structure models will further facilitate future in-depth defect studies to model STCH redox cycle of these oxides.

Notes:

Slideshow presentation.

"2021 Virtual MRS Spring Meeting."

"Funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technologies Office"--Page 17.

Includes bibliographical references.

Description based on online resource; title from PDF title page (NREL, viewed April 22, 2022).

OCLC:

1317708631

Publisher Number:

0000-0001-5991-9562 orcid

0000-0002-8127-8885 orcid

1824290 OSTI ID

Access Restriction:

Publicly released