Enhanced Performance of La₂NiO_4+δ Oxygen-Transporting Membranes Using Crystal Facet Engineering via Microemulsion-Based Synthesis

authored by

Giamper Escobar Cano, Merle Wellmann, Frank Steinbach, Moritz Thiem, Wenjie Xie, Anke Weidenkaff, Armin Feldhoff

Abstract

La₂NiO_4+δ nanorods, synthesized via reverse microemulsion─a crystal facet engineering method─served as building blocks for developing oxygen transport membranes. Comparisons were drawn with ceramic membranes derived from commercial La₂NiO_4+δ nanoparticles. The membrane manufacturing process involved either conventional sintering or the field-assisted sintering technique/spark plasma sintering. The microstructure analysis of the initial powders and the resulting ceramics was thoroughly assessed by X-ray diffraction, scanning and transmission electron microscopy as well as energy-dispersive X-ray spectroscopy. As a consequence of the reaction conditions, the nanorods possess an orthorhombic crystal structure, with LaOBr present as a minor phase. Furthermore, the surface structure of the La₂NiO_4+δ nanorods was discerned via selected area electron diffraction, revealing a composition of (001)_o-type and (1Formula Presented0)_o-type facets on the sides and (110)_o-type facets at the end, with additional facets observed between these surfaces. Among the sintering techniques, spark plasma sintering demonstrated superior performance, when applied to La₂NiO_4+δ nanorods, as it effectively preserved their rod-like nanostructure during the sintering process. The resulting nanorod-derived La₂NiO_4+δ ceramics exhibited excellent oxygen permeation, largely due to the large proportion of orthorhombic (1Formula Presented0)_o-type surfaces in the rod-shaped grains, which correspond to tetragonal (010)_t and (0Formula Presented0)_t surfaces. The (1Formula Presented0)_o-type facets facilitated the oxygen surface exchange, leading to improved oxygen permeation fluxes between 1023 and 1123 K compared to membranes derived from nanoparticles.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry

External Organisation(s)

Technische Universität Darmstadt
Fraunhofer Research Institution for Materials Recycling and Resource Strategies (IWKS)

Type

Article

Journal

Chemistry of materials

Volume

36

Pages

9557-9574

No. of pages

18

ISSN

0897-4756

Publication date

08.10.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Chemistry, General Chemical Engineering, Materials Chemistry

Electronic version(s)

https://doi.org/10.1021/acs.chemmater.4c01570 (Access: Open)