Synthetic Route to Nanocomposites Made Up of Inorganic Nanoparticles Confined within a Hollow Mesoporous Carbon Shell

We present here a novel and simple synthetic strategy for fabricating core/shell materials (diameter ∼400 nm) made up of inorganic nanoparticles confined within a hollow mesoporous carbon shell (shell thickness ∼50 nm). This methodology has been applied to the encapsulation of a variety of inorganic phases such as Fe 3 O 4 /γ-Fe 2 O 3, CoFe 2 O 4, LiCoPO 4, NiO, and Cr 2 O 3 . An important characteristic of these core/shell composites is that, whereas the inner macroporous core can be almost completely filled by nanoparticles, the porosity of the carbon shell hardly contains deposited nanoparticles. In consequence, these materials exhibit large surface areas (∼500−700 m 2 ·g -1 ), high pore volumes (∼0.3−0.6 cm 3 ·g -1 ), and a porosity made up of accessible pores of ∼2−2.5 nm. We demonstrated the usefulness of these composites for the immobilization of an enzyme (lysozyme) and proved their easy manipulation by means of an external magnetic field.