Synthesis of hollow α-Fe2O3–silica composites templated by poly(acrylic acid) colloidal aggregates

Abstract

The synthesis of inorganic hollow nanoparticles has attracted more and more attention in recent research. In this article, hollow α-Fe2O3–silica composites were synthesized by a modified Stober method. Tetraethyl orthosilicate (TEOS) formed oil drops, and ammonia solution facilitated the hydrolysis polymerization of TEOS. In the hydrolysis process of TEOS, we used cetyltrimethylammonium bromide and poly(acrylic acid) colloidal aggregates as the surfactant and template, respectively. The diameters of the composites we obtained are about 20 and 180 nm, respectively, which are smaller than that of pure silica spheres (200 nm). Moreover, Brunauer–Emmett–Teller surface areas of hollow α-Fe2O3–silica composites were determined to be in the range of 377–498 m2/g, and their pore sizes are around 2 nm as were determined by BJH method. The mesoporous silica was successfully coated around the α-Fe2O3. The synthesis process of the composites is a simple, one-step route, which exhibits the potential need for a great amount of synthesis for future research.