Al-Containing Porous Titanium Dioxide Networks: Sol−Gel Synthesis within Agarose Gel Template and Photocatalytic Activity

Al-containing titania porous networks have been produced by conducting sol−gel chemistry within the porous structures of agarose gels. The use of the agarose template gives inorganic materials with a homogeneous macroporous structure. The amount of aluminum added to the titania system was studied from 0 to 10 wt % (where wt % corresponds to the (Al 2 O 3 × 100)/(Al 2 O 3 + TiO 2 ) expected from the initial precursor concentrations), and the morphology and crystallization behavior (as a function of both wt % of Al 2 O 3 and heating temperature) were characterized along with a study of the photocatalytic efficiency of the materials. The 4 wt % sample was found to have the highest photocatalytic activity observed for the photodecomposition of aqueous methylene blue. For low doping amounts, 0.5 and 1 wt % Al 2 O 3, the rutile phase of titania was not observed in the samples heated to 780 °C. Above 4 wt % Al 2 O 3, the temperature required for the anatase to rutile phase transformation increased with increasing amounts of aluminum.