Hierarchical TiO2 photonic crystal spheres prepared by spray drying for highly efficient photocatalysis

Hierarchical inverse opal titania photonic crystal (i-TiO2-PC) spheres have been prepared via spray drying and show highly photocatalytic capability in pollutant elimination. The hierarchical i-TiO2-PC spheres integrated a Mie scattering effect of micro-scale spheres and slow photon effect of photonic crystals with a wavelength-scale period structure, which gave birth to remarkable photocatalytic performance. In the photodegradation of methylene blue under irradiation of UV light, the rate constant of the i-TiO2-PC spheres was 1.66 times, on average, higher than that of Degussa P25.