Abstract
This study investigates phase transitions in CuO/Al2O3 oxygen carriers during chemical looping combustion (CLC), aiming to understand performance and stability over extended redox cycles. In situ quick X-ray assorption spectroscopy (QXAS) was employed to track the transformations of the copper aluminate phase (CuxAlyO4) over 50 redox cycles in various oxidizing (2.5 to 21% O2 in N2) and reducing (H2, CO, CH4) environments. The study reveals that the oxygen carrier undergoes significant phase transitions, reaching a threshold where CuxAlyO4 predominantly converts to copper oxide and α-Al2O3, leading to irreversible structural modifications. Complementary SEM analysis further highlights morphological changes, such as particle growth prior to α-Al2O3 formation. This cycle-dependent phase evolution provides new insights into accelerated ageing mechanism involving the interplay between copper phase transformations and α-Al2O3 formation, which is critical for enhancing the durability of oxygen carriers in CLC applications.
Author(s): Sharna, S (Sharna, Sharmin); Rouchon, V (Rouchon, Virgile); Lambert, A (Lambert, Arnold); Briois, V (Briois, Valerie); Chiche, D (Chiche, David); Gay, AS (Gay, Anne-Sophie); Legens, C (Legens, Christele); Ersen, O (Ersen, Ovidiu)
https://doi.org/10.1039/D5CP00358J
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Volume: 27 Issue: 37 Pages: 20063-20073 Early Access Date: AUG 2025 Published Date: 2025 SEP 24
Accession Number: WOS:001564336800001
PubMed ID: 40910501
ISSN: 1463-9076
eISSN: 1463-9084
