A new kind of heterostructured mesoporous materials for supporting gold nanoparticles was developed by surface modification of mesoporous cellulous foam silica (MCF) with antimony trioxide (Sb2O3) in a monolayer/submonolayer state through a spontaneous dispersion process at 450 A degrees C for 24 h. Gold nanoparticles were well stabilized on the surface of MCF-Sb2O3, exhibiting not only catalytic activity for CO oxidation even below room temperature but also good catalytic stability without the growth of Au nanoparticles after a steady-state reaction for 30 h.