RETRACTED: Rapid one-pot synthesis of Ag-decorated ZnO nanoflowers for photocatalytic degradation of tetracycline and product analysis by LC/APCI-MS and direct probe ESI-MS

Abstract

A high potential nanostructure photocatalyst, Ag-decorated ZnO nanoflowers (Ag/ZnO NFs), was synthesized by a rapid one-pot surfactant-free microwave-assisted aqueous solution method. The morphology, structure, and optical property of Ag/ZnO were well-characterized. The method qualifies to be energy conserving and environment friendly. The size of the flower petals ranges from 200 to 250 nm and highly dispersed Ag nanoparticles (NPs) with dimensions ranging from 10 to 30 nm were anchored onto the surface of them. The as-prepared Ag/ZnO demonstrated enhanced photocatalytic performance in eliminating tetracycline (TC) aqueous solution under the illumination of visible light. The Ag/ZnO exhibited 100% degradation efficiency within 30 min. The effect of operating parameters such as pH, catalyst dose, and TC concentration was investigated. The reaction byproducts were identified by LC/APCI-MS (liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry) and ESI-MSn (electrospray ionization tandem mass spectrometry) analysis and a pathway was proposed as well. Kinetic studies indicated that the photodegradation process follows pseudo-first-order kinetics. The enhanced photocatalytic activity was due to the special architecture, the suppression of electron/hole (e–/h+) pair recombination, and the acceleration of surface charge transfer induced by the highly dispersive Ag NPs, which was further demonstrated by the cyclic voltammetry measurement.