Conjugated dual size effect of core-shell particles synergizes bimetallic catalysis

Core-shell bimetallic nanocatalysts have attracted long-standing attention in heterogeneous catalysis. Tailoring both the core size and shell thickness to the dedicated geometrical and electronic properties for high catalytic reactivity is important but challenging. Here, taking Au@Pd core-shell catalysts as an example, we disclose by theory that a large size of Au core with a two monolayer of Pd shell is vital to eliminate undesired lattice contractions and ligand destabilizations for optimum benzyl alcohol adsorption. A set of Au@Pd/SiO2 catalysts with various core sizes and shell thicknesses are precisely fabricated. In the benzyl alcohol oxidation reaction, we find that the activity increases monotonically with the core size but varies nonmontonically with the shell thickness, where a record-high activity is achieved on a Au@Pd catalyst with a large core size of 6.8nm and a shell thickness of similar to 2-3 monolayers. These findings highlight the conjugated dual particle size effect in bimetallic catalysis.

Automated summary

Core-shell bimetallic nanocatalysts have been widely studied in heterogeneous catalysis. In this study, Au@Pd core-shell catalysts were investigated and it was found that a large Au core with a thin Pd shell is crucial for achieving optimum benzyl alcohol adsorption and high catalytic activity. A series of Au@Pd/SiO2 catalysts with different core sizes and shell thicknesses were fabricated, and it was observed that the activity increased with core size but varied nonmonotonically with shell thickness. The findings reveal the importance of conjugated dual particle size effect in bimetallic catalysis.