Synthesis of Uniform Mesoporous Carbon Capsules by Carbonization of Organosilica Nanospheres

A synthetic method to produce uniform mesoporous hollow carbon nanospheres with a large surface area and uniform mesoporosity has been developed by employing, as carbon source, an organic moiety used as porogen agent to synthesize spherical organosilica nanoparticles with a core@shell (organic−inorganic) structure. The conversion of the organic moiety to carbon is achieved by means of sulphuric acid which considerably increases the carbon yield via dehydration and sulphonation reactions. The carbon capsules exhibit a uniform morphology (a diameter of ∼440 nm and a shell thickness of ∼50 nm), a high Brunauer−Emmett−Teller (BET) surface area (1620 m 2 g −1 ), a large pore volume (2.3 cm 3 g −1 ), and a porosity made up of mesopores centered at around 4.3 nm. Iron oxide magnetic nanoparticles were incorporated into the pores of the porous shell of the carbon capsules. The magnetic hollow nanoparticles were then used as support for the immobilization of the cytochrome C. A large amount of enzyme is stored in this magnetic nanocomposite (∼500 mg Cyt·g −1 support) which suggests that a significant fraction of enzyme is accommodated in the hollow core of the capsules.