Fabrication of highly active metal cluster catalysts through fine tuning of the atom numbers

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Suzuki-Miyaura coupling reaction was performed over the Pd/USY catalyst. Pd/USY exhibited extremely high activity when bubbling with 6% H_2 were applied to the reaction. XAFS analysis revealed the formation of atomic Pd with cationic character in o-xylene. Furthermore, catalytic activity of Pd/USY prepared under different steaming conditions was correlated with the strong Bronsted acid sites arisen from extra-framework Al. Based on these data, atomic Pd anchored on the strong Bronsted acid site of USY zeolite was ascribed to the active species. Au particles undergo spontaneous dispersion on the USY support under H2 atmosphere at a temperature of 773 K to give Au particles with an average diameter of 1. 8 nm and narrow size distribution.