Haoguo Zhu

Comparison of Au Catalysts Supported on Mesoporous Titania and Silica: Investigation of Au Particle Size Effects and Metal-Support Interactions

Au catalysts supported on mesoporous silica and titania supports were synthesized and tested for the oxidation of CO. Two approaches were used to prepare the silica-supported catalysts utilizing complexing triamine ligands which resulted in mesoporous silica with wormhole and hexagonal structures. The use of triamine ligands is the key for the formation of uniformly sized 2–3 nm Au nanoparticles in the silica pores. On mesoporous titania, high gold dispersions were obtained without the need of a functional ligand. Au supported on titania exhibited a much higher activity for CO oxidation, even though the Au particle sizes were essentially identical on the titania and the wormhole silica supports. The results suggest that the presence of 2–3 nm particle size alone is not sufficient to achieve high activity in CO oxidation. Instead, the support may influence the activity through other possible ways including stabilization of active sub-nanometer particles, formation of active oxygen-containing reactant intermediates (such as hydroxyls or O2−), or stabilization of optimal Au structures.

Colloidal deposition synthesis of supported gold nanocatalysts based on Au–Fe3O4 dumbbell nanoparticles

Highly active Au catalysts with a dumbbell-like heterostructure for CO oxidation were prepared through colloidal deposition method; both activities and stabilities were investigated under different experimental conditions.

Oxygen-assisted reduction of Au species on Au/SiO2 catalyst in room temperature CO oxidation

An unexpected oxygen-assisted reduction of cationic Au species by CO was found on a Au/SiO(2) catalyst at room temperature and the produced metallic Au species plays an essential role in CO oxidation on Au/SiO(2).

Seeded growth of robust SERS-active 2D Au@Ag nanoparticulate films

We demonstrate herein a novel and versatile solution-based methodology for fabricating self-organized two-dimensional (2D) Au nanoparticle arrays on glass using in situ nucleation at an aminosilane monolayer followed by seeded, electroless growth; subsequent deposition of Ag produced Au@Ag core–shell nanoparticulate films which proved highly promising as surface-enhanced Raman scattering (SERS) platforms.