In situ growth of TiO2 nanocrystals on g-C3N4 for enhanced photocatalytic performance.

Well dispersed TiO2 nanocrystals with (001) facets were successfully grown in situ on g-C3N4 through a facial solvothermal method. The resultant TiO2/g-C3N4 composites exhibit remarkably higher efficiency for photocatalytic degradation of phenol as compared to pure catalysts (g-C3N4 or TiO2) or mechanically mixed TiO2/g-C3N4. The optimal composite with 11.2 wt% TiO2 showed the highest degradation rate constant, which is 2.8 times that of pure g-C3N4, 2.2 times that of pure TiO2, and 1.4 times that of mechanically mixed TiO2/g-C3N4. The enhanced photocatalytic activity is mainly attributed to the effective charge separation derived from two aspects: (1) well matched energy levels between TiO2 and g-C3N4 and (2) a uniform and close contact between TiO2 and g-C3N4 that resulted from the in situ growth of highly dispersed TiO2 nanocrystals. The TiO2/g-C3N4 hybrid material prepared in this study is expected to provide a good foundation for the further design and synthesis of advanced TiO2/g-C3N4-based functional materials, and the in situ growth method developed is hopeful to provide a new strategy for the synthesis of other semiconductor-modified g-C3N4 materials.