Nanocomposite Fe_2O_3-SiO_2 inclusion pigments from post-functionalized mesoporous silicas

摘要

High-surface mesoporous silicas with different pore sizes were employed for the first time as silicon precursors in the synthesis of reddish Fe_2O_3-SiO_2 inclusion pigments. Interestingly, the size of included Fe_2O_3 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 °C within a ceramic glaze. The best red shade (a* ≈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 Fe_2O_3-SiO_2 ceramic pigments through and adequate control of confinement effects into sintered mesoporous silicas.