Formation of layered Al2O3 and its inhibitory effect on the sintering of supported platinum particles

Abstract The sintering behavior of Pt particles on layered Al 2 O 3 was investigated. Layered Al 2 O 3 was prepared by calcination of a commercially available aluminum hydroxide. The growth of Pt particles on layered Al 2 O 3 was suppressed even in an oxidizing atmosphere at above 1000 °C, and the particle size was greatly affected by the pore diameter of the layered Al 2 O 3 . On the other hand, the particle size of platinum on γ-Al 2 O 3 was drastically increased. The diameters and the supported states of Pt particles were evaluated by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and chemisorption of carbon monoxide. The platinum particles in a highly dispersed state were captured in the pores of layered Al 2 O 3 , so the space for the particles for aggregation or migration was limited.