Design of TiO2/Ag3BiO3 n-n heterojunction for enhanced degradation of tetracycline hydrochloride under visible-light irradiation

Pharmaceutical residual contaminants in aquatic ecosystems have caused severe risks to human health. Affordable, eco-friendly and effective photocatalysts to deal with these pollutants has become a hot topic in the scientific community. In this research, Ag3BiO3 nanoparticles were embedded on TiO2 to form n-n heterojunction through a facile hydrothermal method. According to scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), brunauer emmett teller (BET), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) tests, the successful construction of TiO2/Ag3BiO3 heterojunction is proved. TiO2/Ag3BiO3 het-erojunctions were employed as photocatalysts to remove tetracycline hydrochloride (TCH) under visible light irradiation in aqueous solution. Optimum TCH photodegradation efficiency was observed for TiO2/Ag3BiO3 (10%), 15.4 times superior to that of TiO2. The enhanced TCH photodegradation efficiency of TiO2/Ag3BiO3 results from improved light absorption capacity and the reduction of recombination of photogenerated charge carriers via generation of n-n heterojunctions. The mechanism of increasing the photodegradation efficiency of TCH was determined by employing reactive species quenching experiments. TiO2/Ag3BiO3 (10%) also exhibited an acceptable stability.

Automated summary

Pharmaceutical residual contaminants in aquatic ecosystems pose severe risks to human health. This research presents the development of a visible light photocatalyst, TiO2/Ag3BiO3 heterojunction, for efficient removal of tetracycline hydrochloride. The enhanced removal efficiency is attributed to improved light absorption capacity and suppressed recombination of photogenerated charge carriers through the formation of n-n heterojunctions. The study also elucidates the mechanism behind the improved degradation efficiency.