When the obtained white slurry was removed to Teflon autoclave, the main reaction occurred was Eq. (2). The ZnO crystal was hexagonal, and the anion in crystal was tetrahedron coordination [Zn–O4]6. The angle of ZnO4 was connected, and a three-fold symmetry axis was parallel to the c axis; a side surface was parallel to the cathode surface, the angle of which was corresponded to the negative side point. The ZnO4 tetrahedron was presented in layered distribution along the c-axis. When the dehydrated reaction occurred, ZnO sheet was formed. When the mass ratio of NaOH to Zn(Ac)2 was above 1:1, because OH was abundant in the mixed aqueous solution, freshly formed Zn(OH)2 precipitation (Eq. (1)) could be dissolved immediately by reacting with superfluous OH ions and a transparent
Zn(OH)4 2 solution was obtained (Eq. (3)), as could also been approved by the experimental phenomenon for that white slurry was firstly obtained when the NaOH solution was partly dropped, while the white precipitate gradually disappeared with the following dropping of NaOH. Ultimately a transparent Zn(OH)42 solution was obtained before removed to Teflon autoclave. In the hydrothermal process, the Zn(OH)4 2 growth units combined with each other and dehydrated into ZnO nuclei simultaneously. And then these ZnO nuclei exhibited fast growth orientation [0001]. Finally, ZnO rods were formed.