Synthesis and characterization of bioinspired hierarchical mesoporous TiO₂ photocatalysts

Bioinspired hierarchical mesoporous TiO₂ photocatalysts are prepared by using pollen grains as biotemplate. Physicochemical properties of the as-prepared samples are characterized in detail by X-ray diffraction analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption isotherms. Results indicate that the as-prepared products have a similar structure with the pollen grains, which maintain the ellipsoidal shape and the open pores networks on reticular shells. The Brunauer-Emmett-Teller (BET) surface area is measured and its value is as high as 96.2 m² g¹, which is probably due to the fact that the biomolecules in pollen coats act as mesotemplates during the calcination process and the open macropore networks improve the accessibility of surface. In addition, the products have an excellent photocatalytic activity of RhB, which can be attributed to larger surface areas, anatase phase and similar structure with the pollen grains.