Existence of a Heterogeneous Pathway in Palladium-Catalyzed Carbon-Carbon Coupling Reaction: Evidence from Ag@Pd3Cu Intermetallic Nanoplates

Abstract

Palladium (Pd)-catalyzed cross-coupling reaction is a widely studied process with significant economic interest and represents one of the most successful nanocatalytic examples. Owing to the observed leaching of Pd ions from both monometallic and short-range-ordered Pd bimetallic nanocatalysts, there is ambiguity regarding whether the coupling reaction has a heterogeneous component. Herein, facilitated by theoretical calculations, we discovered that the Pd ion leaching-free Pd3Cu intermetallic compound was able to catalyze the cross-coupling reaction heterogeneously with activity comparable with that of Pd ions leached from monometallic Pd. The observation that Pd3Cu acted as a heterogeneous catalyst was further confirmed by the reaction-promoting effect of hot electrons generated by the Ag core in Ag@Pd3Cu nanoplates upon photon adsorption and could only participate in the reaction on the surface of the nanocatalyst. Additionally, it demonstrated experimentally the effectiveness of the heterogeneous route in the coupling reaction. This study shows that the combination of plasmonic catalysis and intermetallic compounds is a promising strategy for designing robust nanocatalysts to synthesize value-added chemicals.