Title: Substituted SrFeO₃ as robust oxygen sorbents for thermochemical air separation: correlating redox performance with compositional and structural properties

Abstract

Thermochemical air separation via cyclic redox reactions of oxide-based oxygen sorbents has the potential to achieve high energy efficiency. Although a number of promising sorbents have been investigated, further improvements in sorbent performance through a fundamental understanding of the structure–performance relationships are highly desirable. In this study, we systematically investigated the effects of A and B site dopants on the oxygen uptake/release properties (i.e., vacancy formation energy, reduction enthalpy, oxygen release temperature, and oxygen capacity) of the SrFeO₃ family of perovskites as oxygen sorbents. A monotonic correlation between DFT calculated oxygen vacancy formation energy and oxygen release temperature demonstrates the effectiveness of DFT for guiding sorbent selection. Combining vacancy formation energy with stability analysis, dopants such as Ba and Mn have been identified for tuning the redox property of SrFeO₃ sorbents, and increasing the oxygen capacity for temperature and pressure swings when compared to undoped SrFeO₃. The Mn doped sample proved to be highly stable, with less than a 3% decrease in capacity over 1000 cycles. Although the dynamic nature of the redox process makes it difficult to use a single vacancy formation energy as the descriptor, a systematic approach was developed to correlate the oxygen storage capacities with themore » sorbents’ compositional properties and vacancy formation energies. The combination of DFT calculations with experimental studies from this study provides a potentially effective strategy for developing improved sorbents for thermochemical air separation.« less

Authors:

Krzystowczyk, Emily ^[1]; Wang, Xijun ^[1]; Dou, Jian ^[1]; Haribal, Vasudev ^[1]; Li, Fanxing  ^[1]

• Search DOE PAGES for author "Li, Fanxing"
• Search DOE PAGES for ORCID "0000-0002-6757-1874"

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+ Show Author Affiliations

1. North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical and Biomolecular Engineering

Publication Date:

Tue Mar 31 00:00:00 EDT 2020

Research Org.:

North Carolina State University, Raleigh, NC (United States)

Sponsoring Org.:

USDOE Office of Fossil Energy (FE); USDOE

OSTI Identifier:

1799924

Alternate Identifier(s):

OSTI ID: 1615033

Grant/Contract Number:  

FE0031521

Resource Type:

Accepted Manuscript

Journal Name:

Physical Chemistry Chemical Physics. PCCP

Additional Journal Information:

Journal Volume: 22; Journal Issue: 16; Journal ID: ISSN 1463-9076

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY