The porous TiO2/pg-C3N4 composite photocatalyst was successfully prepared by combining ultrasonic with hydrothermal treatment. XRD, SEM, TEM, UV-Vis DRS and PL were applied to analyze its morphology, structure and optical properties. The photocatalytic activities of the as-prepared samples were evaluated by degradating the simulated pollutants (RhB, MO) in aqueous solution under simulated sunlighti llumination. The result showed that the TiO2/pg-C3N4 (5:100) exhibited the best photocatalytic degradation performance among all photocatalists with different compositions. The photocatalytic degradation pathway of RhB was chromophore cleavage caused by O2- and h+. The improved photocatalytic performance of TiO2/pg-C3N4 (5:100) was attributed to the fact that the active sites of the photocatalytic reaction were increased due to the porous structure, on the one hand, and a Z-scheme type heterojunction was formed between TiO2 and pg-C3N4 on the other hand, which not only can increase the separation efficiency of electron-hole pairs, but also can retain the stronger reducibility of photo-generated electrons on the more negative CB of pg-C3N4 and higher oxidationability of photo-generated holes on the more positive VB of TiO2, compared with the conventional type II heterojunction.
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