The growth mechanism of zinc oxide and hydrozincite: a study using electron microscopies and in situ SAXS

The growth mechanism of ZnO is investigated by a combination of electron microscopy and in situ small-angle X-ray scattering (SAXS). The particles are prepared by the precipitation of zinc nitrate with urea. Depending on the reaction conditions, ZnO, hydrozincite, or a mixture of both phases is detected in our system. The molecular precursors and complexation reactions of the formation process are numerically predicted by the partial-charge model. The condensation and complexation reactions lead to the formation of nanoparticle building units up to a size of 10 nm. Afterwards, the nanoparticles immediately self-assemble into micro-sized particles.