Tuning the structure of a hierarchically porous ZrO₂ for dye molecule depollution

A novel strategy that tailors porous zirconia structures via a control of zirconium alkoxide reactivities has been developed. This control was achieved by limiting the amount of water present in the system through the use of an acetonitrile medium. Varying the amount of water present during the reaction has led to a better understanding of the self-formation phenomenon of hierarchical porosity. The choice of zirconium alkoxide precursor has also been studied. The porosity of the zirconia can be altered simply by tuning the water:acetonitrile ratio. A significant change in the porous structure has been observed with increasing water content. This revelation has led to a better understanding of the formation of hierarchically porous structures and the development of a very efficient and simple method to tailor hierarchical porosity over different length scales. The synthesized zirconia products, with differing porous structures, showed a very high adsorption capacity for dye molecules in aqueous solution. A relationship between the porous structure and the adsorption capacity of dye molecules has been evidenced, suggesting their potential application in water treatment as decontamination materials.