Biotemplated hierarchical TiO2–SiO2 composites derived from Zea mays Linn. for efficient dye photodegradation

Abstract

Five typical silicon-accumulating tissues (including leaves, roots, stalks, silks, and husks) of corn plant (Zea mays Linn.), for the first time, were applied as both structure-directors and silicon-precursors to synthesize biomorphic hierarchical porous TiO2–SiO2 composites. By combination of an effective microwave-assisted HCl pretreatment and a simple in situ growth, the hierarchical porous architectures of corn tissues and silicon bodies were inherited into the obtained TiO2 frameworks, which led to both of the structure- and SiO2-introduced enhancements of photocatalytic performances. UV–visible absorption spectra indicate that all TiO2–SiO2 prepared as above exhibit enhanced visible-light harvesting efficiencies, especially in the range from 400 to 750 nm. Moreover, N2 sorption measurements show that biotemplated composite derived from corn leaves has 2.5 times higher specific surface area than that of the commercial P25. Using methylene blue as the target pollutant, all biomorphic TiO2–SiO2 were proved to possess strong adsorption abilities and enhanced photocatalytic activities. The present work may provide a new route for the fabrication of hierarchical porous silicon-based materials based on silica-rich plants and develop a new method to protect the natural environment by utilizing waste biomass.