Abstract: Ordered porous alumina films with a controllable pore size were fabricated by anodization and applied to simulate realistic catalyst supports. The support morphology dependence of the silver particle agglomeration on the Ag model catalyst loaded on this ordered porous anodic alumina was studied. Scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy were used to characterize the morphologies, compositions, and chemical properties of the model catalyst. When the average pore size of the alumina substrate is smaller than 50 nm, both the agglomeration and the growth of silver particles are suppressed greatly. But when the pore size is bigger than 200 nm, the agglomeration and growth of silver particles occur to some extent, while the confinement effect still exists. This confinement effect can efficiently prevent active components on catalysts from aggregation.

Key words: porous anodic alumina, silver, agglomeration, ethylene, epoxidation