A general nonaqueous sol-gel route to g-CN-coupling photocatalysts: the case of Z-scheme g-CN/TiO with enhanced photodegradation toward RhB under visible-light.

The g-CN-coupling TiO photocatalysts with controllable particle size as well as the interface contact were prepared by a general nonaqueous sol-gel method. The structural and morphological features of g-CN/TiO were investigated through the X-ray diffraction, Fourier transformed infrared spectra, scanning electron microscopy and transmission electron microscopy, respectively. It is found the TiO nanoparticles with a size of 7.3 ± 1.6 nm are uniformly anchored on the surface of the g-CN nanosheets in isolation. The photocatalytic properties of as-prepared g-CN/TiO were tested by degradation of Rhodamine B (RhB) under visible light, and an enhanced activity is observed. The mechanism of the enhanced activity was further investigated through N adsorption-desorption isotherms, UV-vis spectra, photoluminescence spectra, photoelectrochemical measurements, radical trapping experiments and X-ray photoelectron spectroscopy. Furthermore, the photocatalytic performances of obtained g-CN/TiO under sunlight were also evaluated in aspects of degradation efficiency and stability. The results indicate that the obtained g-CN/TiO is one promising photocatalyst for practical applications. The study of as-prepared g-CN/TiO also implies that the present method could be a general route of g-CN-coupling photocatalysts.