Synthesis of hierarchically porous TiO 2 nanomaterials using alginate as soft templates

Abstract We herein report a large-scale synthesis of hierarchically porous TiO 2 structures composed of nanoparticles by a facile soft-template method. The natural and abundant biopolymer named alginate acted as sacrificial templates, providing porous structures and controlling the morphology of TiO 2 nanoparticles. The size of the resultant TiO 2 nanoparticles was around 20 nm. The TiO2 structures were obtained by directly crosslinking Ti 4+ ions to alginate and then burning off the biopolymer templates. Based on the observation of various reactive conditions, we propose that the alginate has two important function in the formation of hierarchically porous TiO 2 structures. One is acting as a template for the nucleation of TiO 2 . The other one is to facilitate the formation of porous TiO 2 nanomaterials. The photocatalytic property of hierarchically porous TiO 2 in UV-light-driven degradation of organic dyes was proved to be better than that of commercial available TiO 2 .