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Aqueous Isolation of 17‐Nuclear Zr/Hf Oxide Clusters during the Hydrothermal Synthesis of ZrO 2 /HfO 2
Author(s) -
Sun Qing,
Liu Caiyun,
Zhang Guanyun,
Zhang Jian,
Tung ChenHo,
Wang Yifeng
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201801267
Subject(s) - hydrothermal circulation , oxide , aqueous solution , nucleation , hydrothermal synthesis , ionic bonding , cluster (spacecraft) , nanocrystal , zirconium , materials science , ionic conductivity , inorganic chemistry , nanomaterials , ion , chemistry , chemical engineering , nanotechnology , organic chemistry , programming language , electrode , computer science , electrolyte , engineering , metallurgy
Novel 17‐nuclear Zr/Hf oxide clusters ({Zr 17 } and {Hf 17 }) are isolated from aqueous systems. In the clusters, Zr/Hf ions are connected through μ 3 ‐O, μ 3 ‐OH, and μ 2 ‐OH linkages into a pinwheel core which is wrapped with SO 4 2− , HCOO − , and aqua ligands. Octahedral hexanuclear Zr/Hf oxide clusters ({Zr 6 } oct and {Hf 6 } oct ) are also isolated from the same hydrothermal system by decreasing the synthesis temperature. Structures, synthetic conditions, vibrational spectra, and ionic conductivity of the clusters are studied. Structural studies and synthesis inspection suggest that formation of {Zr 6 } oct and {Zr 17 } involves assembly of the same transferable building blocks, but the condensation degree and thermodynamic stability of the products increase with hydrothermal temperature. The role of {Zr 6 } oct and {Zr 17 } in the formation of ZrO 2 nanocrystals are then discussed in the scenario of nonclassical nucleation theory. In addition, the Zr oxide clusters exhibit ionic conductivity owing to the mobility of protons. This study not only adds new members to the Zr/Hf oxide cluster family, but also establishes a connection from Zr 4+ ions to ZrO 2 in the hydrothermal preparation of zirconium oxide nanomaterials.