Exceptional Antisintering Gold Nanocatalyst for Diesel Exhaust Oxidation

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Gold nanoparticles (NPs) exhibit poor thermodynamic stability, hindering their use at high temperatures.
• Stabilizing small gold NPs is crucial for catalytic applications but challenging due to sintering.

Purpose of the Study:

• To prepare an antisintering gold nanocatalyst with enhanced stability at elevated temperatures.
• To investigate the mechanism behind the enhanced stability of gold nanoparticles on a specific support.

Main Methods:

• Theoretical prediction and rational selection of a MgGa2O4 spinel support with sublattice matching.
• Synthesis of gold nanoparticles supported on MgGa2O4 (Au/MgGa2O4).
• High-temperature aging studies (above 1064 °C) and characterization of the resulting nanostructures.

Main Results:

• Au/MgGa2O4 retained 2-5 nm gold NPs even after aging above gold's melting point.
• A novel Au-MgGa2O4 metal-oxide "hetero-bicrystal" phase was identified as the source of stability.
• Over 80% of loaded gold was stabilized, leading to excellent low-temperature activity for diesel exhaust oxidation post-aging.

Conclusions:

• The developed Au/MgGa2O4 catalyst demonstrates exceptional thermal and hydrothermal stability.
• The hetero-bicrystal structure is key to preventing gold nanoparticle sintering.
• This work provides a pathway for designing robust gold nanocatalysts for industrial applications.