|Apr 08, 2020|
Tracking the atomic pathways by in-situ liquid cell TEM(Nanowerk News) Recently, platinum-containing core-shell structures with tunable magnetic and catalytic properties have attracted intensive attentions and offered a wide range of applications. To date, their synthetic routes are mostly based on galvanic replacement, co-reduction, thermal decomposition and seed-mediated method.
|But the detailed formation mechanisms of core-shell structures in solution, especially, at gas-liquid interface are still not completely clear, which is mostly achieved based on post reaction studies or ex situ characterizations.|
|In this regard, it is worthwhile but still very challenging to directly visualize the complicate and delicate dynamic processes.|
|Technical advantages of in-situ liquid electron microscopy (TEM) allow us to monitor the growth trajectory of pure metal nanoparticles in liquid media, including nucleation growth, nanorod self-assembly, and electrochemical deposition.|
|Compared with pure metal nanocrystals, the growth pathway for alloy and its oxide core-shell structures is more complicated. It is noteworthy that little is known about the atomic growth pathway of Pt based-oxide core-shell structures and structural stability in solution, especially, at the gas-liquid interface. Due to the lack of direct observation method with high spatial resolution, some intermediate states may be easily missed.|
|In a new report (Science China Chemistry, "Tracking the atomic pathways of Pt3Ni-Ni(OH)2 core-shell structures at the gas-liquid interface by in-situ liquid cell TEM"), Honggang Liao's group first observed the atomic growth way of Pt3Ni-Ni(OH)2 core-shell structure at gas-liquid interface using in-situ liquid cell TEM.|
|Experiment results revealed the underlying growth and transformation mechanisms of the Pt3Ni-Ni(OH)2 core-shell structure by systematically changing the Ni:Pt ratio in the precursor solution and tuning electron beam dose rate. Key questions regarding the growth mechanism for single- and multi-layer Ni(OH)2 flakes were addressed. It is anticipated that this work could provide atomic insights on the rational design of metal-2D core-shell structures for potential wide range applications.|
|Source: Science China Press|
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