Hydrothermal synthesis of zinc hydroxide chloride sheets and their conversion to ZnO

We report a simple hydrothermal slow cooling process to synthesize zinc hydroxide chloride (ZHC) powders consisting of large-sized single-crystal sheets. The lateral size of the sheetlike products can be tuned from 20 to 500 mu m through the control of pH condition of the starting zinc chloride solution and the amount of the solute. The growth mechanism of the ZHC sheets is explained by dissolution at high temperatures and precipitation during slow cooling. The ZHC single-crystal sheets were converted to highly oriented polycrystalline zinc oxide sheets by calcination at 500 degrees C for 5 h in air.