Design of a photocatalyst for bromate decomposition: Surface modification of TiO(2) by pseudo-boehmite

The rate of BrO(3)(-) reduction by a commercial TiO(2) photocatalyst under UV illumination in an aqueous solution was increased by lowering the pH from 7 to 5. The effect is attributable to an enhancement of the electrical interaction between BrO(3)(-) and the positively charged surfaces of the TiO(2) photocatalyst. The surface charge can be controlled by a surface modification of the TiO(2) photocatalyst without controlling the pH of the water. In fact, the isoelectric point of surface-modified TiO(2) was higher than that of the unloaded TiO(2) photocatalyst, resulting in an increase in the rate of the photocatalytic reduction of BrO(3)(-) at a neutral pH. This increase is explained by an increase in the amount of adsorbed BrO(3)(-) on the photocatalyst surface.