ZnO nanorods were prepared by a simple reflux route, employing Zn(NO3)2 and urea as the reactants.
The flowerlike Zn4(OH)6CO3·H2O precursor was firstly formed in the starting stage of the reaction.
The formation of ZnO nanorods underwent a conversion from Zn4(OH)6CO3·H2O to ZnO.
The nanotube was an inevitable intermediate product during the shape transformation process.