Hydrothermal synthesis of Cu-doped ZnS for enhanced photocatalytic degradation of tetracycline under the visible light

Abstract Undoped and Cu-doped ZnS were sucessfully synthesized by hydrothermal method. X-ray diffraction, Fourier transform infrared spectrometer, scanning electron microscope, transmission electron microscopy and UV-vis spectrophotometer were used to characterize the synthesized products. Characterization results indicated that Cu has been successfully doped into ZnS, and the doped material was smaller and had looser surface. In addition, the band gap was decreased from 3.50 eV to 2.27 eV through doping of Cu. Photocatalytic degradation of tetracycline confirmed the superiority of Cu-doped ZnS compared with ZnS, and the electron paramagnetic resonance and quenching experiment were used to investigate the photocatalytic mechanism, ·OH was regarded as the dominant species for tetracycline oxidation degradation. The effects of tetracycline concentration and catalyst dosage were further studied. Also, the good stability of Cu-doped ZnS was demonstrated via the 5-cycle test.