Synthesis and characterization of magnetic core with two shells: Mordenite zeolite and CuO to form Fe3O4@MOR@CuO core-shell: As a visible light driven photocatalyst

Abstract

In the present study, for the first time the synthesis of magnetic Fe3O4 as core with separate two shells, mordenite (MOR) zeolitic shells and CuO shells, was suggested. The new core-shell (Fe3O4@MOR@CuO) was prepared in three steps: (i) preparation of iron oxide magnetite core via hydrothermal method with diameter size between 120 and 150 nm, (ii) development of mordenite (MOR) zeolite as first shells on the Fe3O4 cores (Fe3O4@MOR) by hydrothermal method with thickness between 30 and 50 nm and (iii) coating of second shells from CuO by post-synthesis method with average thickness 215 nm. The properties of prepared magnetic core-shells were characterized by diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurement and vibration sample magnetometer (VSM). Based on EDX results, the weight percentage (wt%) of Fe3O4 cores, MOR and CuO shells were calculated 68.13, 28.17 and 3.7%, respectively. The XRD results indicated diffraction peaks for each three compounds in core-shell. The diffuse reflectance spectrum of Fe3O4@MOR@CuO photocatalyst presented a strong absorption in the 400–800 nm range, indicating the introduction of MOR broadened the visible light absorption ability. The photodecolorization of Fe3O4@MOR@CuO core-shell was investigated in the absence and presence of H2O2. The results showed that, zeolitic shells and Fe3O4 enhanced charge separation efficiency compared with that of the pure CuO and Fe3O4@CuO core-shell in photodegradation of methylene blue (MB) dye. The photocatalyst exhibited an enhanced and stable activity for the degradation of MB under visible light. The mechanism of separation of the photogenerated electrons and holes of the Fe3O4@MOR@CuO photocatalyst was discussed.