Novel urchin-like Fe₂O₃@SiO₂@TiO₂ microparticles with magnetically separable and photocatalytic properties

Novel urchin-like microparticles with photocatalytic activity and magnetically separable properties were prepared by a layer-by-layer assembly process. Photocatalytic degradation was investigated using two types of mercury vapor lamps: an ozone generating lamp emitting at both 254 nm and 185 nm as well as a germicidal lamp emitting at 254 nm only. This novel photocatalyst demonstrated superior photocatalytic activity in the mineralization of phenol under UVC illumination compared with the commercial P25, Degussa TiO₂, especially in repeated usage. Importantly, this photocatalyst can be quickly separated for reuse simply by using a magnet. The merits of 3D spiny nanostructured TiO₂ microparticle photocatalysts are high specific surface area, good permeability, reduced charge recombination rate and high catalytic activity while the incorporation of magnetically separable properties enables rapid and easy retrieval of the suspended photocatalyst after use.