Synthesis of Ag and Cd nanoparticles by nanosecond-pulsed discharge in liquid nitrogen

作     者：Mahmoud Trad Alexandre Nominé Natalie Tarasenka Jaafar Ghanbaja Cédric Noel Malek Tabbal Thierry Belmonte 

作者机构：Universite de LorraineCNRSIJLF-54000 NancyFrance B.I. Stepanov Institute of PhysicsNational Academy of Sciences of BelarusMinskBelarus Department of PhysicsAmerican University of BeirutBeirutLebanon 

出 版 物：《Frontiers of Chemical Science and Engineering》 (化学科学与工程前沿（英文版）)

年 卷 期：2019年第13卷第2期

页      面：360-368页

核心收录：

学科分类：0817[工学-化学工程与技术] 08[工学] 0703[理学-化学] 

基　　金：from the support of the project CEENEMA of the French National Research Agency (ANR) 

主　　题：spark discharges submerged discharges timeresolved optical emission spectroscopy liquid nitrogen 

摘      要：The synthesis of CdO, Ag2O (5nm) and Ag (~20~30 nm) nano-objects is achieved simultaneously by nanosecond-pulsed discharges in liquid nitrogen between one cadmium electrode and one silver electrode. Oxidation occurs when liquid nitrogen is fully evaporated and nanoparticles are in contact with the air. No alloy is formed, whatever the conditions, even though both elements are present simultaneously, as showed by timeresolved optical emission spectroscopy. This lack of reactivity between elements is attributed to the high pressure within the discharge that keeps each metallic vapor around the electrode it comes from. Each element exhibits a specific behavior. Cubic Cd particles, formed at 4 kV, get elongated with filamentary tips when the applied voltage reaches 7 and 10 kV. Cd wires are formed by assembly in liquid nitrogen of Cd nanoparticles driven by dipole assembly, and not by dielectrophoresis. On the contrary, silver spherical particles get assembled into 2D dendritic structures. The anisotropic growth of these structures is assumed to be due to the existence of pressure gradients.