Photocatalytic Degradation Mechanism of Tetracycline by Ag@ZnO/C Core-Shell Plasmonic Photocatalyst Under Visible Light

A series of hamburger-like Ag@ZnO/C core-shell plasmonic photocatalysts have been synthesized via a simple solvothermal method for degradation of tetracycline (TC) under visible light irradiation, possessing high photocatalytic activity and good stability. The presence of localized surface plasmon resonance (LSPR) in the Ag core has increased the photocatalytic activity over an extended wavelength range. The plasmon-induced resonant energy transfer (PIRET) and direct electron transfer (DET) have facilitated the excitation and separation of photogenerated e(-)/h(+) pairs, which has been further confirmed by electrochemical investigations. The presences of hydroxyl radicals (center dot OH), superoxide radicals (center dot O-2(-)) and singlet oxygen (O-2(-)) in the photocatalytic reaction system of Ag@ZnO/C photocatalyst have been demonstrated by electron spin resonance (ESR) measurements. All of the experiment results indicate that the ternary structure of Ag@ZnO/C can effectively enhance the photocatalytic activity. Furthermore, the effects of introduced Ag contents and carbon source dosage were researched by comparative photocatalytic experiments, and the potential structures of photodegradation products were studied by HPLC-MS.