BiO and g-CN quantum dot modified anatase TiO heterojunction system for degradation of dyes under sunlight irradiation.

A facile and feasible method was successfully utilized to incorporate BiO and g-CN quantum dots on TiO surface to synthesize a novel composite g-CN/TiO/BiO. The photocatalytic activity of the composite g-CN/TiO/BiO for degradation of dyes under sunlight and UV light irradiation was evaluated. It possessed the higher photocatalytic performance than that of pristine TiO or g-CN under the same conditions. Under sunlight irradiation, the reaction rate constants of the g-CN/TiO/BiO was about 4.2 times and 3.3 times higher than that of TiO and g-CN, respectively. The promising photocatalytic performance was attributed to the broader light absorption range and efficient separation of photoinduced carriers. Moreover, based on the TEM, XPS, XRD, UV-vis spectrum, radicals scavenging test and Mott-Schottky analysis systematic mechanism for photodegradation process was proposed. This work provides a promising strategy for the modification of TiO-based semiconductors by incorporating different quantum dots and promoting the efficiency of the photocatalysts in practical application.