Development of monolithic titanium dioxide ceramic photocatalysts with high physical rigidity and photocatalytic activity for underwater use

A monolithic TiO2 ceramic photocatalyst, which retains its stability underwater, was developed. A mixture of TiO2 nanocrystalline colloidal sol mixed with activated carbon was used as a precursor; it was dried and calcined to yield a monolithic TiO2 ceramic photocatalyst. The crystal phase of this ceramic was TiO2 single-phase anatase calcined up to 550 degrees C; it began to transform to the ruffle phase at high temperatures. The surface area of the ceramic photocatalyst decreased with an increase in the calcination temperature; that is, a surface area of 74 m(2)/g at 500 degrees C decreased to 2 m(2)/g at 750 degrees C. The photocatalytic activity was maximum at 550 degrees C, while it decreased to 2% at 750 degrees C. Long-term stability was tested for three months under a continuous water flow (tap water); the weight of the monolithic TiO2 ceramic photocatalyst remained constant.