Synthesis of Z-scheme g-C3N4-Ti(3+)/TiO2 material: an efficient visible light photoelectrocatalyst for degradation of phenol.

In this study, a photocatalytic material g-C3N4-Ti(3+)/TiO2 nanotube arrays was prepared by a facile and viable approach involving a heat treatment followed by an electrochemical reduction step, and it was characterized using instrumental techniques such as X-ray diffraction pattern, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and UV-vis diffuse reflectance spectra. The photocatalytic efficiency of the as-prepared samples towards treating aqueous solution contaminated with phenol was systematically evaluated by a photoelectrocatalytic method and found to be highly dependent on the content of the g-C3N4. At the optimal content of g-C3N4, the apparent photocurrent density of g-C3N4-Ti(3+)/TiO2 was four times higher than that of the pristine TiO2 under visible-light illumination. The enhanced photoelectrocatalytic behavior observed for g-C3N4-Ti(3+)/TiO2 was ascribed to a cumulative impact of both g-C3N4 and Ti(3+), which enhances the photoresponsive behavior of the material into the visible region and facilitates the effective charge separation of photoinduced charge carriers.