In Situ Observation of Dynamic Galvanic Replacement Reactions in Twinned Metallic Nanowires by Liquid Cell Transmission Electron Microscopy

Abstract

Galvanic replacement is a versatile approach to prepare hollow nanostructures with controllable morphology and elemental composition. The primary issue is to identify its fundamental mechanism. In this study, in situ liquid cell transmission electron microscopy was employed to monitor the dynamic reaction process and to explore the mechanism of galvanic replacement. The detailed reaction process was revealed based on in situ experiments in which small Au particles first appeared around Ag nanowires; they coalesced, grew, and adhered to Ag nanowires. After that, small pits grew from the edge of Ag nanowires to form tubular structures, and then extended along the Ag nanowires to obtain hollowed structures. All of our experimental observations from the viewpoint of electron microscopy, combined with DFT calculations, contribute towards an in‐depth understanding of the galvanic replacement reaction process and the design of new materials with hollow structures.

Kirkendall Effect Boosts Phosphorylated nZVI for Efficient Heavy Metal Wastewater Treatment

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Initiation and Progression of Anisotropic Galvanic Replacement Reactions in a Single Ag Nanowire: Implications for Nanostructure Synthesis

“…An LPTEM cell that allows flow provides advantages in studying the GRR: (1) observing the full process, especially at the early stage of the reaction. 14,19 (2) Constant Au precursor concentration can be achieved by replenishing the liquid flow.…”

Open-ended W18O49-filled tungsten dichalcogenide nanotubes grown on a W substrate to efficiently catalyze hydrogen evolution

“…As demonstrated by other researchers, precise control over the microstructures of nanocatalysts is crucial to optimize HER properties. [27][28][29] In this work, we were able to precisely control the top-capping feature of aligned TMDs nanotubes through implementing a simple growth control, which has been proven quite effective in improving the catalysis efficacy due to increased active edge sites.…”