Visible Light Photocatalytic Degradation of Methylene Blue over N-Doped TiO2

The visible light photocatalytic degradation of methylene blue (MB) over N-doped TiO2 (N-TiO2) was investigated. The intermediate products of MB in the photocatalytic degradation process were analyzed by HPLC-MS technique. The results show that the cleavages of CS+=C and CN=C functional group in the central aromatic ring and the cleavage of N-C bond between the methyl group and nitrogen atom all can occur in the visible light photocatalytic degradation process over N-TiO2, but MB is difficult to be mineralized completely to the inorganic products. A detailed degradation pathway of MB has been proposed on the basis of a careful identification of intermediate products.