Amphiphilic Self-Assembly of Nanocrystals at Emulsion Interface Renders Fast and Scalable Quasi-Nanosheet Formation

• Published in: ACS applied materials & interfaces Vol. 14; no. 44; pp. 50354 - 50362
• Main Authors: Xi, Xiangyun, Wan, Siyu, Deng, Yuwei, Xia, Yan, Xiao, Jingyu, Cao, Yangfei, Huang, Xianwu, Li, Zhicheng, Yang, Dong, Dong, Angang, Li, Tongtao
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 31.10.2022
• Subjects: Surfaces, Interfaces, and Applications; self-assembly; amphiphilic; electrocatalysis; nanocrystals; nanosheets
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c14274

Scalable assembly of nanocrystals (NCs) into two-dimensional (2D) nanosheets has aroused great interest, yet it remains under-explored. This is because current 2D assembly methods rely mainly on the use of solid– or liquid–air interfaces, which are inherently difficult for upscaling and thus lack practicability. Here, with a microemulsion-based amphiphilic assembly technique, we achieve a fast and scalable preparation of free-standing nanosheets comprising few-layer, tightly packed NCs, namely, quasi-nanosheets (quasi-NSs). Acetic acid, acting as both solvent and surface-treatment agent, is used to render the initially hydrophobic NCs amphiphilic, while simultaneously inducing the interfacial instability right after the assembly of NCs at the emulsion interface to afford quasi-NSs. This amphiphilic assembly method is applicable to a variety of NCs, and multicomponent quasi-NSs are also attainable upon coassembly of different types of NCs. In addition, the structural advantages of quasi-NSs in catalysis are showcased by using NiFe2O4 quasi-NSs as electrocatalysts for the oxygen evolution reaction. This work opens a new route for the scalable construction of 2D NC sheets with designated components and functions.