Solventless Preparation of Thoria and Its Inclusion into SiO and TiO: A Luminescence and Photocatalysis Study.

Thoria was prepared using a solid-state method from the macromolecular precursor Chitosan·Th(NO) (chitosan) and PS-co-4-PVP·Th(NO) (PVP). The morphology and the average size of ThO depend of the chitosan and PS-co-4-PVP polymer forming the precursor. Their photoluminescent properties were investigated, finding a dependence of their intensity emission maxima, with the nature of the precursor polymer. The photocatalytic activity of ThO toward the degradation of methylene blue was measured for the first time, finding a degradation of about 66% in 300 min. The inclusion of ThO into SiO and TiO was achieved by the solid-state pyrolysis of the macromolecular composites Chitosan·Th(NO)//MO and PS-co-4-PVP·Th(NO)//MO, MO = SiO or TiO. The ThO exhibits a homogeneous dispersion inside the silica, showing sizes of about 40 and 50 nm for the chitosan and PVP polymer precursors, respectively. The luminescent properties of the ThO/SiO and ThO/TiO composites were also studied, finding a decrease in intensity when introducing the SiO or TiO matrices. The photocatalytic behavior to methylene blue degradation of ThO and their composites ThO/SiO and ThO/TiO was investigated for the first time, with them in the following order: ThO > ThO/TiO > ThO/SiO.