2.3. Measurement
Material morphologies were observed by using a field emissionscanning electron microscope (FE-SEM, type: Hitachi S-4800). X-ray diffraction (type: RINT-1500) was used to check the crystallinity and estimate the crystal sizes of the mesoporous TiO2 spheres.N2 absorption isotherms were measured at −196◦C by using a Micromeritics system.