A novel CeO2–TiO2/PANI/NiFe2O4 magnetic photocatalyst: Preparation, characterization and photodegradation of tetracycline hydrochloride under visible light

Abstract

A novel CeO2–TiO2/PANI/NiFe2O4 magnetic photocatalyst was successfully prepared by hydrothermal, sol-gel and ultrasonic impregnation method. The composition, morphological and optical property of the samples were characterized by XRD, FT-IR, UV–vis DRS, SEM, XPS and other characterization methods. The results show that CeO2–TiO2/PANI/NiFe2O4 has narrower band gap and better visible light response ability, and possesses better photo-generated electron hole pairs separation capability than that of pure TiO2, CeO2–TiO2 and CeO2–TiO2/NiFe2O4 photocatalysts, and the degradation rate of tetracycline hydrochloride can reach 92.6% under the optimal conditions. The photocatalytic reaction rate constant of CeO2–TiO2/PANI/NiFe2O4 is the largest (0.037 ​min−1), which is 9.27 times, 1.95 times and 1.28 times of that of TiO2, CeO2–TiO2 and CeO2–TiO2/NiFe2O4, respectively. The CeO2–TiO2/PANI/NiFe2O4 composite photocatalyst exhibits a superior stability after three consecutive reuses. The improvement of the photocatalytic performance of CeO2–TiO2/PANI/NiFe2O4 composite photocatalyst may be due to the fact that some Ce ions enter into the lattice of TiO2, which narrows the band gap and broadens the spectral response range. CeO2, NiFe2O4 and TiO2 form semiconductor heterojunction, which can effectively separate photo-generated electron hole pairs. In addition, a possible dual Z-scheme electron transfer mechanism of CeO2–TiO2/PANI/NiFe2O4 composite catalyst was proposed by free radical capture experiments in this study.