Two-Dimensional Porous SiO2 Nanostructures Derived from Renewable Petal Cells with Enhanced Adsorption Efficiency for Removal of Hazardous Dye

Diverse microstructures and morphologies from plant cells inspire us with great opportunities for creating novel nanomaterials. In this work, a biomorphic mesoporous SiO2 with unique two-dimensional (2D) nanostructure was feasibly fabricated by employing renewable petal cells as bioscaffolds. During the structure formation, the hydrolyzed siliceous species initially adhere to and then penetrated the cell walls, forming the composite of siliceous species/cells. This is followed by shrinkage and deformation of the cell skeleton in a subsequent drying process. Then, the special 2D SiO2 with abundant internal mesopores was acquired after careful removal of the cells. The concentration of siliceous source (tetraethyl orthosilicate, TEOS) in the impregnation/infiltration steps is a key factor for the replication of the biological morphology for SiO2. The sample prepared with C-TEOS of 0.05 mol L-1 can duplicate well the biomorphology of petal cells, which has a BET surface area of 177 m(2) g(-1) and pore size ranging from 4 to 9 nm. Because of its highly accessible pores and large attachable adsorption sites, the biomimetic 2D porous SiO2 displays significant adsorption capacity for methylene blue (74 mg g(-1)), which is higher than those by nonporous SiO2 (14 mg g(-1)) and the traditionally hydrothermally synthesized mesoporous SBA-15 (45 mg g(-1)).