Hydrothermal and surfactant treatment to enhance the photocatalytic activity of hierarchically meso-macroporous titanias

The photocatalytic activities of various hierarchically meso-macroporous titanias, obtained via a spontaneous self-formation process using titanium isopropoxide, have been investigated by comparing each materials' capability to photodegrade Rhodamine B. Three synthesis routes have been developed to synthesize hierarchically meso-macroporous titania materials: (A) in water without and (B) with hydrothermal treatment and (C) in a surfactant Brij 56 aqueous solution with hydrothermal treatment, respectively. These results show that the introduction of surfactant Brij 56 and a hydrothermal treatment in the synthesis system greatly improve the crystallinity of the anatase phase in hierarchically meso-macroporous titanias and their thermal stability, resulting in a remarkable enhancement of their photocatalytic activity. Furthermore, the effect of calcination on hierarchically porous structure and their photocatalytic activity has also been investigated in detail. The properties of the products were characterized by XRD, SEM and N-2 adsorption-desorption measurements. (C) 2012 Elsevier B.V. All rights reserved.