Growth of Au–Pd₂Sn Nanorods via Galvanic Replacement and Their Catalytic Performance on Hydrogenation and Sonogashira Coupling Reactions

Abstract

Colloidal PdSn and Au-PdSn nanorods (NRs) with tuned size were produced by the reduction of Pd and Sn salts in the presence of size- and shape-controlling agents and the posterior growth of Au tips through a galvanic replacement reaction. PdSn and Au-PdSn NRs exhibited high catalytic activity toward quasi-homogeneous hydrogenation of alkenes (styrene and 1-octene) and alkynes (phenylacetylene and 1-octyne) in dichloromethane. Au-PdSn NRs showed higher activity than PdSn for 1-octene, 1-octyne, and phenylacetylene. In Au-PdSn heterostructures, X-ray photoelectron spectroscopy evidenced an electron donation from the PdSn NR to the Au tips. Such heterostructures showed distinct catalytic behavior in the hydrogenation of compounds containing a triple bond such as tolan. This can be explained by the aurophilicity of triple bonds. To further study this effect, PdSn and Au-PdSn NRs were also tested in the Sonogashira coupling reaction between iodobenzene and phenylacetylene in N, N-dimethylformamide. At low concentration, this reaction provided the expected product, tolan. However, at high concentration, more reduced products such as stilbene and 1,2-diphenylethane were also obtained, even without the addition of H. A mechanism for this unexpected reduction is proposed.

Synthesis and potential applications of trimetallic nanostructures

“…The GRR approach is carried out via the differences of the reduction potential between the replacing and replaced metals at moderate temperature, minimizing the homonucleation of independent NPs. 91 In the GRR route, one metal NP is used as a template and the other metals that have higher reduction potentials are reduced and deposited on the template to provide core-shell, hybrid, or hollow multi-metallic structures. Wang et al 92 developed a GRR route to prepare Au-Cu-X (X = Pt, Pd, and Ag) using Au-Cu nanorods as the templates and further extended it to Au-Cu-Pt, Au-Cu-Pd, and Au-Cu-Ag by the diffusion of the metal precursors.…”

Azo(xy) vs Aniline Selectivity in Catalytic Nitroarene Reduction by Intermetallics: Experiments and Simulations

“…For example, Pd 2 Sn nanoparticles are active catalysts in the removal of nitrate from water, ethanol oxidation, − oxygen reduction, and H 2 O 2 generation . Pd 2 Sn nanoparticles on Au are active in Sonogashira coupling, as well as in alkene and alkyne hydrogenation . PdSn, Pd 3 Sn 2 , and Pd 2 Sn nanoparticles chemoselectively hydrogenate crotonaldehyde, with PdSn nanoparticles having a high selectivity for the reduction of CO vs CC bonds .…”

Gold Nanoparticles Grown by Galvanic Replacement on Graphene-Coated Aluminum Panels as Large-Area Substrates for Surface-Enhanced Raman Scattering

“…Different nanomaterial morphologies, such as nanocubes, 1 nanohexagonal particles, 2 nanodendrites, 3,4 nanoparticles, 5,6 nanorods, 7,8 nanobelts, 9 and others, 10−12 can be fabricated using GR reactions. Consequently, GR-based nanocomposites have been applied to various fields, such as catalysis, 7,13,14 biosensing, 15−17 surface-enhanced Raman scattering (SERS), 10,18−21 and electrochemical applications. 8,22 SERS, one of the key applications of nanomaterials, has attracted considerable interests because it can provide higher sensitivity than conventional Raman spectroscopy, selective detection, water-free interference, and abundant chemical information.…”