Phase-dependent Al leaching and crystal structure stability of CoAl2O4 in alkaline media
4 affiliations
- 1Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634 Republic of Singapore
- 2Institute of Advanced Intelligence and Computing (IAIC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632 Republic of Singapore
- 3Institute of Sustainability for Chemicals, Energy and Environment (ISCE²), Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island, Singapore, 627833 Republic of Singapore
- 4Present Address: Mark Wainwright Analytical Center, University of New South Wales, Sydney, NSW 2052 Australia
Abstract
Surface changes have attracted great interest in solid synthesis, catalysis and corrosion. Herein, we demonstrate a distinct surface Al/Co ratio-dependent reconstruction behavior in alkaline media for sol-gel-derived CoAl2O4 particles. Our results indicate that the nominal Al/Co = 2 represents an average composition for particles formed at low temperatures, with spinel Al-excess surfaces and Al-poor cores. Annealing at high temperature homogenizes the cation distribution by the progressive incorporation of surface-Al into the core. Upon exposure to alkaline solution, the Al-excess surface phases are selectively leached and stabilize at a new spinel-type Al-rich surface. In contrast, no selective leaching is observed in normal spinel CoAl2O4 with a homogeneously single phase. These unexpected findings highlight the surface-composition dependent phase dissolution and the progressive incorporation of atoms into specific crystal structures during multi-metal oxide synthesis, hence drawing attention to the neglected relay-like phase formation of each single compound before the final-phase formation of mixed metal compounds.
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BibTeX
@article{sun2026phasedependent,
title = {{Phase-dependent Al leaching and crystal structure stability of CoAl2O4 in alkaline media}},
author = {Shengnan Sun and Hui Ru Tan and Peng Zhao and Shibo Xi and Fengxia Wei and Debbie Hwee Leng Seng and Yi Ren and Jia Zhang and Ming Lin and Zhi Wei Seh},
journal = {Nature Communications},
year = {2026},
month = sep,
doi = {10.1038/s41467-026-78099-3},
url = {https://doi.org/10.1038/s41467-026-78099-3},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Phase-dependent Al leaching and crystal structure stability of CoAl2O4 in alkaline media
AU - Shengnan Sun
AU - Hui Ru Tan
AU - Peng Zhao
AU - Shibo Xi
AU - Fengxia Wei
AU - Debbie Hwee Leng Seng
AU - Yi Ren
AU - Jia Zhang
AU - Ming Lin
AU - Zhi Wei Seh
PY - 2026
DA - 2026/09/28
JO - Nature Communications
DO - 10.1038/s41467-026-78099-3
UR - https://doi.org/10.1038/s41467-026-78099-3
AB - Surface changes have attracted great interest in solid synthesis, catalysis and corrosion. Herein, we demonstrate a distinct surface Al/Co ratio-dependent reconstruction behavior in alkaline media for sol-gel-derived CoAl2O4 particles. Our results indicate that the nominal Al/Co = 2 represents an average composition for particles formed at low temperatures, with spinel Al-excess surfaces and Al-poor cores. Annealing at high temperature homogenizes the cation distribution by the progressive incorporation of surface-Al into the core. Upon exposure to alkaline solution, the Al-excess surface phases are selectively leached and stabilize at a new spinel-type Al-rich surface. In contrast, no selective leaching is observed in normal spinel CoAl2O4 with a homogeneously single phase. These unexpected findings highlight the surface-composition dependent phase dissolution and the progressive incorporation of atoms into specific crystal structures during multi-metal oxide synthesis, hence drawing attention to the neglected relay-like phase formation of each single compound before the final-phase formation of mixed metal compounds.
SN - 2041-1723
ER -