γ-Alumina-supported Pt 17 cluster: controlled loading, geometrical structure, and size-specific catalytic activity for carbon monoxide and propylene oxidation.

Although Pt is extensively used as a catalyst to purify automotive exhaust gas, it is desirable to reduce Pt consumption through size reduction because Pt is a rare element and an expensive noble metal. In this study, we successfully loaded a Pt 17 cluster on γ-alumina (γ-Al 2 O 3 ) (Pt 17 /γ-Al 2 O 3 ) using [Pt 17 (CO) 12 (PPh 3 ) 8 ]Cl n ( n = 1, 2) as a precursor. In addition, we demonstrated that Pt is not present in the form of an oxide in Pt 17 /γ-Al 2 O 3 but instead has a framework structure as a metal cluster. Moreover, we revealed that Pt 17 /γ-Al 2 O 3 exhibits higher catalytic activity for carbon monoxide and propylene oxidation than γ-Al 2 O 3 -supported larger Pt nanoparticles (Pt NP /γ-Al 2 O 3 ) prepared using the conventional impregnation method. Recently, our group discovered a simple method for synthesizing the precursor [Pt 17 (CO) 12 (PPh 3 ) 8 ]Cl n . Furthermore, Pt 17 is a Pt cluster within the size range associated with high catalytic activity. By combining our established synthesis and loading methods, other groups can conduct further research on Pt 17 /γ-Al 2 O 3 to explore its catalytic activities in greater depth.