Nanocomposite Fe2O3-SiO2 inclusion pigments from post-functionalized mesoporous silicas

High-surface mesoporous silicas with different pore sizes were employed for the first time as silicon precursors in the synthesis of reddish Fe2O3-SiO2 inclusion pigments. Interestingly, the size of included Fe2O3 nanoparticles was partially controlled through confinement effects into silica mesopores. Notably, impregnated samples showed a more homogeneous and efficient encapsulation of smaller and monodisperse hematite nanoparticles (sizes around 10-35 nm). Moreover, they resulted in an improved reddish color at 1000 degrees C within a ceramic glaze. The best red shade (a*approximate to 18) was associated to nanocomposite with smaller hematite nanoparticles (around 5 nm). These promising results suggest the possibility to improve the reddish coloration and thermostability of Fe2O3-SiO2 ceramic pigments through and adequate control of confinement effects into sintered mesoporous silicas. (C) 2009 Elsevier Ltd. All rights reserved.