Visible Light Harvesting Titania-Coated Diatom Frustules with Superior Photocatalytic Activity
Porous silica frustules of diatoms are naturally occurring microcellular, solar light harvesting hierarchical structures. In this work, titania-deposited diatom frustule is presented as a heterogeneous catalyst having high efficiency for photodegradation of major pollutants under visible light irradiation. The heterogeneous catalyst is synthesized by depositing titania nanoparticles in the pores and surface of diatom frustules by solgel method and is characterized by XRD, UV–visible absorption spectroscopy, SEM, and TEM. Increase in crystallite size with the transformation of titania phase at high-temperature synthesis is confirmed by XRD. UV–visible spectra reveal that synthesized catalysts exhibit absorption in the visible light range and are able to perform catalytic activity for the degradation of azo-dyes. The effect of photocatalyst on dye concentration in aqueous solution and presence of anatase–rutile titania phases are also presented. As-prepared catalysts responsive to visible light could be a promising candidate in application of environment remediation by harvesting solar energy with the use of the morphology of diatom frustules and presence of nano titania phases in it.
KeywordsDiatom frustule Mixed phase Band gap Rate constant Degradation
- 7.Ibhadon, A.O., Fitzpatrick, P.: Heterogeneous photocatalysis: recent advances and applications. Catalysts 3, 189–218 (2013)Google Scholar
- 9.De Tommasi, E., Rea, I., De Stefano, L., Dardano, P., Di Caprio, G., Ferrara, M.A., Coppola, G.: Optics with diatoms: towards efficient, bioinspired photonic devices at the micro-scale. SPIE Proc 8792, 87920O-1 (2014)Google Scholar
- 12.Available at: http://westerndiatoms.colorado.edu/taxa/species/cosmioneis_reimeri. Accessed 14th Sep 2016