Synthesis of Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres for efficient aqueous phenol photocatalytic degradation

Abstract

This study aims to synthesize a ternary Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres by modified Stöber technique to photodegrade aqueous phenol under UV-C light effectively. Results of the X-ray diffractogram of the as-synthesized Fe3O4-NH2-APTES@rGO@SiO2 core–shell magnetic microspheres showed the nanoparticles having an average size of 126.00 nm, comparable to 150.00 nm seen in the FESEM micrograph. These sizes were supported by the EDX and FTIR results which verified the presence of Fe3O4, rGO, and SiO2, and the TEM micrograph revealed them to be spherically shaped. Also, the thermally more stable microspheres than the pure individual components and binary nanocomposites were evident in their corresponding TGA thermograms.Similarly, the photoluminescence spectra of the Fe3O4-NH2-APTES@rGO@SiO2 microspheres supported their higher photodegrading ability as a consequence of an extended e-/h+ recombination rate. The microspheres were more effective in photo-catalytically degrading the highest amount of aqueous phenol (∼89 %) than Fe3O4-NH2-APTES@rGO (∼74 %), Fe3O4-NH2-APTES@SiO2 (∼78 %), and pure Fe3O4 (∼62 %), under an optimized condition of 0.2 g/350 mL catalyst loading and 50 ppm of initial phenol concentration. The enhanced photoactivity was ascribed to the high stability and specific surface of SiO2, the synergistic influence of Fe3O4, and the rGO sheet’s rapid electron transport·H2O2 enhanced phenol degradation to 94 %.

Keywords

• Modified Stöber method
• Fe3O4-NH2-APTES@rGO@SiO2 microsphere
• Phenol
• Photodegradation