Pd@Pt Core–Shell Nanoparticles with Branched Dandelion-like Morphology as Highly Efficient Catalysts for Olefin Reduction

Graphical Abstract

Flower power: Highly branched core–shell nanoparticles (NPs) with a micro–mesoporous dandelion-like morphology, comprising a Pd core and Pt shell, catalyze the efficient reduction of a variety of olefins in good to excellent yields. Their superior catalytic activity is due in part to the unique micro–mesoporous structure.

Abstract

A facile synthesis based on the addition of ascorbic acid to a mixture of Na₂PdCl₄, K₂PtCl₆, and Pluronic P123 results in highly branched core–shell nanoparticles (NPs) with a micro–mesoporous dandelion-like morphology comprising Pd core and Pt shell. The slow reduction kinetics associated with the use of ascorbic acid as a weak reductant and suitable Pd/Pt atomic ratio (1:1) play a principal role in the formation mechanism of such branched Pd@Pt core–shell NPs, which differs from the traditional seed-mediated growth. The catalyst efficiently achieves the reduction of a variety of olefins in good to excellent yields. Importantly, higher catalytic efficiency of dandelion-like Pd@Pt core–shell NPs was observed for the olefin reduction than commercially available Pt black, Pd NPs, and physically admixed Pt black and Pd NPs. This superior catalytic behavior is not only due to larger surface area and synergistic effects but also to the unique micro–mesoporous structure with significant contribution of mesopores with sizes of several tens of nanometers.