New active meso-porous titania foam as size limiter for metal nanoparticles

Abstract

We present here a new sustainable method to fabricate peculiar titania mesofoam (mF), showing open cells with homogeneous size and shape for applications in heterogeneous catalysis. The mF was fabricated from an aqueous suspension of monodisperse polystyrene beads in diluted titanium acetylacetonate. The acetylacetonate group is proposed to be the driving force for the adsorption of the metal complex on the polystyrene beads. On top of the obtained anatase foam, we deposited gold nano-particles as an example of catalytically active metal nanoparticles, where the size of the metal nanoparticles was very sensitive to the temperature of catalytic tests. The resulting catalyst was fully characterized for application in the catalytic oxidation of CO and C3H6. The catalytic activity is strongly influenced by thermal treatments which increase the mean Au particle size distribution of the catalyst. Nevertheless, the proposed method for mF fabrication is able to generate mesopores that delimit the size of the gold nanoparticles to the mesopore size of the foam (i.e at average size below 10 nm) even in severe reaction conditions. This unusual attitude of the mF to delimit the gold nanoparticle size might also be effective for other metal nanoparticles. Consequently, we foresee that the proposed method could open a new route foractive inorganic mF, as support for metal nanoparticles.