A Series of Unique Architecture Building of Layered Zinc Hydroxides: Self-Assembling Stepwise Growth of Layered Zinc Hydroxide Carbonate and Conversion into Three-Dimensional ZnO

A series of uniformly unique three-dimensional (3D) structures of layered zinc hydroxides (LZHs) were synthesized via a hydrothermal method. During the process, two kinds of LZHs with different crystal structures could be formed, depending on the ionic groups intercalated in zinc hydroxide layers: when carbonate anions were the only interlayer ions, the corresponding LZH compound was assigned as LZHC or zinc hydroxide carbonate; when the interlayer ions contained both carbonate anions and long-chain quaternary ammonium groups, the corresponding LZH compound was denominated as LZHDC. Interestingly, the LZHDC is transformed into LZHC though a structure and compositional transformation involving an exchange of long-chain quaternary ammonium groups by carbonate anions. We propose a stepwise growth and anion exchange mechanism involving conversion from zinc precursor to LZHDC to LZHC. We demonstrated the utility the LZHs obtained in the process as self sacrificial templates for formation novel 3D ZnO structures by pyrolysis.