Immobilization and photocatalytic efficiency of titania nanoparticles on silica carrier spheres

Immobilization of titania nanoparticles on submicron-sized silica carrier spheres was achieved, and the relevant photocatalytic efficiency was studied. In contrast to the commonly adopted practice of either free suspending nano-sized catalyst particles or immobilized catalyst particles on large supports for photocatalytic applications, the present approach offers a third option, avoiding the disadvantages of the above-mentioned two practices. In the model system of photo-degradation of methylene blue, the photocatalytic efficiency of the present catalyst form was found comparable to that of free-suspending P25 nanoparticles, a popular commercial titania photocatalyst, of the same total catalyst surface area. The present photocatalytic process was found to be diffusion dominant, and its impressive catalytic performance was attributed to the well-separated, smaller than usual titania particles immobilized on the surfaces of submicron-sized silica spheres.