Synthesis and studies of ZnO doped with g-C3N4 nanocomposites for the degradation of tetracycline hydrochloride under the visible light irradiation

Abstract

Herein, ZnO@CN nanocomposites synthesized by facile thermal decomposition strategy by using ZIF-8 as a precursor and examined the photodegradation studies against antibiotic tetracycline hydrochloride (TC) as a pollutant. The characterization of ZnO@CN was done by different analytical techniques such as XRD, FT-IR, SEM, DRS, XPS, PL and EIS which indicated that the composite has a narrow bandgap, hexagonal- shaped nanobolts structure, high stability, maximum ability to absorb visible light spectrum, high adsorption ability, and excellent charge separation. It was observed that a balanced ratio of ZnO and CN play a vital role in charge separation and provide standard bandgap which participates to boost-up photocatalytic degradation under visible light. As compared with pure CN and ZnO, the composites ZnO@CN-2 showed more efficient photocatalytic activity for TC degradation under the visible - light spectrum. The most advantageous CN amount in ZnO@CN-2 nanocomposite exhibited 2.77- and 1.51-times faster photodegradation as compared to CN and ZnO respectively. The cyclic process investigated the stability of the photocatalyst. The results showed that after washing five times, there was no significant change observed in the rate of degradation. Moreover, the coupling of CN with ZnO facilitates the photodegradation phenomena by providing active sites, producing rich oxygen species and limiting the electrons and hole recombination, which lead to better degradation of TC under the solar irradiation spectrum.