Significantly enhancement of photocatalytic performances via core–shell structure of ZnO@mpg-C3N4

Abstract

ZnO@mpg-C3N4 photocatalysts with core–shell structure were synthesized via a facile ultrasonic dispersion method. The thickness of the shell can be adjusted by tuning the amount of mpg-C3N4, which is closely connected with the photocatalytic activity. The ZnO@mpg-C3N4 sample at a weight ration of 4% (mpg-C3N4/ZnO) has the highest UV light photocatalytic activity which is almost 2.0 times as high as that of pure ZnO. While the visible light photocatalytic activity of ZnO@mpg-C3N4 increases with the increase of the loading amount of mpg-C3N4. The enhanced UV photocatalytic activity of the ZnO@mpg-C3N4 photocatalysts could be attributed to the hybridized effect between ZnO and mpg-C3N4. The photogenerated holes on ZnO could easily transfer to mpg-C3N4, making charge separation more efficient and reducing the probability of recombination. The enhancement of the visible light photocatalytic activity is due to the heterojunction interfaces and the core–shell structure induced by the match of lattice and energy level between the C3N4 shell and ZnO core. The C3N4 shell absorbs the visible light, and then generates the excited-state electrons. The excited electron on C3N4 could directly inject into the CB of ZnO, making ZnO@mpg-C3N4 present remarkable visible light photocatalytic activity.