Direct Observation of Hollow Bimetallic Nanoparticle Formation through Galvanic Replacement and Etching Reactions.

Wang, Wenhui; Erofeev, Ivan; He, Ya; Yang, Fangqi; Yan, Hongwei; Lu, Jiong; Mirsaidov, Utkur · Nano Lett · 2023

basic_science · Level V

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Abstract

Hollow bimetallic nanoparticles (NPs) formed from metal oxide NP templates are widely used catalysts for hydrogen evolution and CO<sub>2</sub> reduction reactions. Despite their importance in catalysis, the details of how these NPs form on the NP templates remain unclear. Here, using <i>in situ</i> liquid-phase transmission electron microscopy (TEM) imaging, we describe the conversion of Cu<sub>2</sub>O template NPs to hollow PdCu NPs. Our observations show that a polycrystalline PdCu shell forms on the surface of the template via a galvanic replacement reaction while the template undergoes anisotropic etching. This study provides important insights into the synthesis of hollow metallic nanostructures from metal oxide templates.