Well-defined gold nanoclusters with average size less than 2 nm have emerged as a new and novel catalyst. The gold nanocluster loaded on the oxide surface usually aggregates to larger particles at high temperature （〉 300℃）, which is caused by the removal of the surface ligands. We herein pre-sent a novel method to prepare Au25cluster catalyst （-1.3 nm） with high thermal stability （up to 400℃）. Au25@Si02 is synthesized via a co-hydrolyzing reaction of Au2s[SC3H6Si（OCH3）3118 and tet-raethyl orthosilicate, and then it is treated at different temperature （e.g., 200, 300, 400℃） in air to remove the organic ligands. Au25@SiO2 is well characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and diffuse reflectance UV-vis spectroscopy. Further, the Au2s@SiO2 catalysts are investigated in the hydrogenation ofp-nitrophenol into p-aminophenol.
