Z-scheme TiO 2 /g-C 3 N 4 composites with improved solar-driven photocatalytic performance deriving from remarkably efficient separation of photo-generated charge pairs

Abstract High recombination rate of electron-hole pairs and weak oxidation ability of holes from g-C 3 N 4 greatly limit the catalytic degradation efficiency of g-C 3 N 4 -based photocatalysts, thus it is crucial to further improve the photocatalytic efficiency of g-C 3 N 4 . In this paper, TiO 2 was successfully loaded onto the g-C 3 N 4 surface to induce the electron−hole separation and enhance the photocatalytic efficiency. The results revealed the maximum photocatalytic performance toward discoloration of methyl orange (MO) aqueous solution under the simulated sunlight illumination at molar ratio of 3% TiO 2 to g-C 3 N 4 composite. The junction between TiO 2 and g-C 3 N 4 significantly accelerate the separation of the photo-generated charge pairs caused by the strong interactions between TiO 2 and g-C 3 N 4 . Such highly efficient photo-generated charge separation can be explained by a Z-scheme charge separation and migration mechanism based on the results of the scavenger experiments and the energy band structures.