A template self-assembly strategy to synthesize free-standing TiO2–MO (M = Mg, Co, Ni, Cu or Zn) colloidal films

A series of binary free-standing colloidal films, TiO2–MO (M = Mg, Co, Ni, Cu and Zn) have been synthesized via a self-assembly technology, utilizing sodium dodecyl sulfonate (SDS) as template and the mixture of titanium butoxide and MCl2 as precursor. X-ray diffraction (XRD) and transmission electron microscope (TEM) have been employed to characterize TiO2–MO samples. Results show that TiO2–MO films are mainly composed by well-ordered nanostructures (e.g. mesoporous particles and lamellar pieces) and more importantly, the increased Ti(OC4H9)4 precursor have significant effect on modifying the as-synthesized nanostructures. A structural model based on SDS micellar template, the complex metallic oxide precursor and charge-density matching between the template and precursor has been proposed. Remarkably, this template self-assembly method has a potential to design a variety of functional multicomponent materials with high-ordered nanostructures, such as high gas sensing SnO2–ZnO films.