Fabrication and characterizations of silica composite microspheres immobilized with porphyrins and their photocatalytic properties

► The SiO2-S-APTSPP photocatayst shows significantly improved photocatalytic activity under visible-light illumination. ► The SiO2-S-APTSPP photocatayst is stable, harmless and can be reused with highly efficiency. ► The water-soluble metal-free porphyrin is chemisorbed on the surface of silica microspheres. ► The morphology of the photocataysts is uniformity with a diameter of ca. 3-7 μm.