Metalloporphyrins-sensitized titania-silica-iron oxide nanocomposites with high photocatalytic and bactericidal activities under visible light irradiation

•Colloidal nanocomposites of iron oxide-SiO2-TiO2-metalloporphyrins were prepared.•The superparamagnetic composites are active photocatalysts under visible light.•Effects of metals on the photocatalytic activities were investigated.•The composites exhibits bactericidal activity under visible light activation.