Gold Nanoparticle Superlattice in Porous Silica and Low Temperature Catalytic CO Oxidation

Abstract

The practical use of nanoparticle superlattices (NPSLs) which are of great interest as materials with designed functionalities is often limited by their lack of structural stability under various utilization conditions. Here, we report a new method for directly synthesizing NPSL fully embedded in hierarchically porous silica which provides exceptional stability and efficient pathways for reactant molecules, making the NPSL highly efficient catalyst. The superlattices made of 12 nm gold nanoparticles exhibit exceptionally high catalytic activity for CO oxidation at low temperature, showing higher activity than that of small gold nanoparticles (ca. 3 nm) supported on metal oxides. The gold NPSL also shows unprecedented stability, maintaining its structural stability and catalytic activity without any signature of degradation over a month of continuous catalytic reaction, which present one significant step forward to realizing the great potentials of gold catalysts in automotive emission control and green chemistry industry.