Figure 2.

TEM images of (A) ZnO NPs on montmorillonite with nanocrystal aggregation; reprinted with permission from [85], copyright 2004 American Chemical Society; (B) TiO₂@HNTs nanoarchitecture showing the titania NP assembled inside the lumen of the halloysite tubes; adapted with permission from [123], copyright 2011 American Chemical Society; and (C) ZnO@sepiolite where the ZnO NPs were generated on the external surface of the fibrous clay from zinc acetylacetonate following the protocol described in [87].