Bi2O3 and g-C3N4 quantum dot modified anatase TiO2 heterojunction system for degradation of dyes under sunlight irradiation

Abstract

A facile and feasible method was successfully utilized to incorporate Bi₂O₃ and g-C₃N₄ quantum dots on TiO₂ surface to synthesize a novel composite g-C₃N₄/TiO₂/Bi₂O₃. The photocatalytic activity of the composite g-C₃N₄/TiO₂/Bi₂O₃ for degradation of dyes under sunlight and UV light irradiation was evaluated. It possessed the higher photocatalytic performance than that of pristine TiO₂ or g-C₃N₄ under the same conditions. Under sunlight irradiation, the reaction rate constants of the g-C₃N₄/TiO₂/Bi₂O₃ was about 4.2 times and 3.3 times higher than that of TiO₂ and g-C₃N₄, 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 TiO₂-based semiconductors by incorporating different quantum dots and promoting the efficiency of the photocatalysts in practical application.