Structure of P-25 (Degussa) TiO_2 Powder and the origin of Its High Photocatalytic Activity

摘要

A TiO_2 powder (Degussa, P-25) shows high activity as photocatalyst and has often been used in photocatalytic reactions. The powder contains anatase and rutile phases. The structure was investigated by means of TEM observation and HF treatment. The two phases were found to exist separately, forming their agglomerates. Under the conditions of photocatalytic reactions in liquid phase, however, the particles are dispersed, and the fine anatase particles are loaded on rutile particles. This structure is concluded to be important for some reactions.