In situ Study of Oxidative Etching of Palladium Nanocrystals by Liquid Cell Electron Microscopy

Abstract

Oxidative etching has widely prevailed in the synthesis of a crystal and played a critical role in determining the final growth behavior. In this Letter, we report an in situ microscopic study on the oxidative etching of palladium cubic nanocrystals by liquid cell scanning transmission electron microscopy. The etching was realized with oxidative radiation reactants from electron-water interaction in the presence of Br(-) ions. Dissolution dynamics of monodispersed and aggregated nanocrystals were both investigated and compared. Analyses on the dissolution kinetics of nanocrystals and the diffusion kinetics of the dissolved agents were carried out based on the scanning transmission electron microscopy characterizations. The results presented here pave a way toward the quantitative understanding of the oxidative etching reaction and its application in the functionally orientated fabrication of nanocrystals with certain sizes, structures, and morphologies.

Tailoring the Edge Sites of 2D Pd Nanostructures with Different Fractal Dimensions for Enhanced Electrocatalytic Performance

“…According to the results of controlled trials (Figure S12, Supporting Information) in which the additive amounts of the specific chemicals were changed, the etching process was triggered by the joint effect of O 2 , and Br − as reported in the literatures (Figure S12a, Supporting Information),35, 36 while the proton or H + is also crucial to accelerate this etching process (Figure S12b,c, Supporting Information). It is worth noting that AA plays two different roles as reductant and acid, whose weight can be adjusted with the addition of NaAc as weak base (Figure S12d, Supporting Information).…”

Opportunities and challenges in liquid cell electron microscopy

“…As well as visualizing the formation of compact nanoparticles, beam-induced growth experiments also show how templates can alter nanoparticle nucleation (66), how beaminduced growth can form extended structures like dendrites (67,68), and how patterned deposits can be made by rastering the beam (39,42). Liquid cell microscopy can also image corrosive dissolution of nanoparticles (69,70). The balance between oxidizing and reducing species produced by radiolysis can lead to situations in which the beam intensity controls particle stability (40,71).…”

Giant Radiolytic Dissolution Rates of Aqueous Ceria Observed in Situ by Liquid‐Cell TEM

“…This has only rather recentlyb een possible thankst ot he novel "liquid-cell" TEM technology. [17] AB romine etching study on Pd nanoparticles is presented in, [18] whileaparticlegrowth study from Ce-nitrate solution is now also available. The electron beam penetrating the sandwich of membranes and water-particle suspension can be used for the dual purposeo fl ive imaging at only slightly impaired TEMr esolution, but also for deliberate irradiation studies.…”