In-situ growth of all-solid Z-scheme heterojunction photocatalyst of Bi7O9I3/g-C3N4 and high efficient degradation of antibiotic under visible light

Abstract To reduce the recombination of electron-hole pairs, broaden the response scope to visible light, improve the synthesis method and enhance the photocatalytic efficiency of graphite phase carbon nitride (g-C3N4), a novel all-solid direct Z-scheme heterojunction photocatalyst was successfully constructed by in situ growth of bismuth oxyiodide (Bi7O9I3) on ultrathin g-C3N4. The synthesis process was finished under a normal pressure and temperature without any toxic or harmful reagents. As-prepared photocatalyst of BCN-0.2 can be easily excited under visible light and shows an excellent photo-degradation and mineralization capacity of doxycycline hydrochloride. Oxhydryl and superoxide radicals are dominant. Moreover, the Z-scheme heterojunction Bi7O9I3/g-C3N4 has quite stable crystal structure and recycling ability. The present work exhibits a mild and feasible synthesis method for an all-solid direct Z-scheme heterojunction to improve the photocatalytic ability of pollutants.