Synthesis and enhanced visible light-induced photocatalytic activity of a hierarchical porous biomorphic N/Zn–TiO2@NH2-MIL-125 photocatalyst

Heterojunction is considered as very promising material for various applications in photocatalysis. Herein, an efficient heterojunction photocatalyst N/Zn–TiO 2 @NH 2 -MIL-125 was successfully synthesized for photo-degradation organic oxidation by biological-templated method. The electron–hole pairs can be separated in space more efficiently because of heterojunction structure. Systematical analyses of spectroscopy and microscopy measurements revealed that N/Zn–TiO 2 @NH 2 -MIL-125 heterojunction materials exhibited hierarchical porous structure with high surface area of 366.02 m 2  g −1 and outstanding optical properties. Photocatalytic activity was investigated by degradating of rhodamine B (1000 µM) under visible-light irradiation. The N/Zn–TiO 2 @NH 2 -MIL-125 showed enhanced photocatalytic activity for RhB degradation, which is respectively about 1.81 and 1.97 times higher than that of the pristine N/Zn–TiO 2 and NH 2 -MIL-125. Various advanced spectroscopic characterizations were applied including photoluminescence, Mott–Schottky curves and electrochemical impedance spectroscopy. A possible mechanism of enhanced photocatalytic oxidation activity for N/Zn–TiO 2 @NH 2 -MIL-125 composite under visible light irradiation was discussed.