Synthesis and characterization of hydrozincite and its conversion into zinc oxide nanoparticles

Faceted nanoparticles of zinc oxide were successfully achieved via thermal annealing of hydrozincite (Zn5(CO3)2(OH)6) powder at different annealing temperatures, i.e. 300, 500 700 and 900 °C in air for 2 h using sol–gel method by refluxing for 6 h at 70 °C. Zinc acetate dihydrate (Zn(CH3COO)2·2H2O) was used as precursor with urea (NH2CONH2) for the synthesis of hydrozincite. The morphological observations by field emission scanning electron microscope indicated increase in particle size from 20 to 300 nm with increase in the annealing temperatures. High resolution TEM and SAED measurement indicate the distance between two lattice fringes is ∼0.52 nm corresponding to (0 0 0 1) fringes. A standard peak of zinc oxide was observed at 457 cm−1 from the FTIR analysis. Thermo gravimetric analysis (TGA) revealed that the primary weight loss starts at ∼130 °C due to solvent evaporation and the secondary weight loss due to phase transition from hydrated zinc oxide to zinc oxide was observed at ∼290 °C.