SYNTHESIS, PROPERTIES AND PRACTICAL APPLICATIONS OF DOPED AND UNDOPED, ZINC-CONTAINING LAYERED DOUBLE HYDROXIDES - A BRIEF REVIEW
Recently, layered double hydroxides (LDHs) have been developed for more potential applications in various industry fields. Many synthesis methods of LDHs in the literature have been considered and classified by changing properties. However, the property change by the synthesis method does not happen in the same way in all LDHs. Also, when LDH with the same composition is synthesized by the same synthesis method, it is possible to obtain LDHs with the same composition but different properties due to the change of reaction parameters. Recently, the doping of semiconductor nanocomposites with different element atoms has led to new properties. The effect of the elements used in the doping process on the properties of zinc-containing LDHs was investigated and explained in the review article. The synthesis's techniques differ from each other by the reaction parameters and they impact the crystal structure, physicochemical properties, and morphology of LDHs. Finding more additional effects of doping processes and doping elements' nature on the zinc-containing LDHs' properties, the synthesis procedures, and the determination of reaction parameters are shown in this review article. It was revealed that rare earth elements are not selected as three valence metals for the main structure of LDHs, they are mainly used as a doping element which is replaced by three valence metals (Al, Cr, Ti, Fe(III)) as dopants because of the ionic radius and various factors.