The poor thermodynamic stability of gold nanoparticles (NPs) makes it very challenging to stabilize them in small sizes at elevated temperatures. Herein, we report the preparation of antisintering Au nanocatalyst by rationally selecting the sublattice matched MgGa2O4 spinel as support based on theoretical predictions. Au/MgGa2O4 retains Au NPs of 2-5 nm even after aging over the melting temperature of bulk gold (1064 °C)! By identifying the stable structure, the extraordinary stability is found to arise from the formation of a new phase structure, namely Au-MgGa2O4 metal-oxide "hetero-bicrystal" that remains as crystallite without melting even at 1100 °C. More than 80% of the loaded Au can be efficiently stabilized so that the catalysts can exhibit excellent low-temperature activities for diesel exhaust (CO and C3H6) oxidation after severely thermal and hydrothermal aging. These results may pave ways for constructing antisintering gold nanocatalysts for industrial applications.
Keywords: CO oxidation; Gold nanocatalyst; antisintering; diesel oxidation catalyst; metal-oxide heterobicrystal; propene combustion.