Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen--颗粒学报PARTICUOLOGY

Hamdan, A., Kabbara, H., Noël, C., Ghanbaja, J., Redjaimia, A., & Belmonte, T. (2018). Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen. Particuology, 40, 152-159. https://doi.org/10.1016/j.partic.2017.10.012

Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen

Ahmad Hamdan ^{a 1}, Hiba Kabbara ^a, Cédric Noël ^{a b}, Jaafar Ghanbaja ^a, Abdelkrim Redjaimia ^a, Thierry Belmonte ^{a b *}

a Université de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy F-54042, France
b CNRS, Institut Jean Lamour, UMR CNRS 7198, Nancy F-54042, France

10.1016/j.partic.2017.10.012

Volume 40, October 2018, Pages 152-159

Received 5 July 2017, Revised 28 October 2017, Accepted 31 October 2017, Available online 15 February 2018, Version of Record 28 July 2018.

E-mail: thierry.belmonte@univ-lorraine.fr

Highlights

• Two-dimensional lead oxide sheets were synthesized by discharge in liquid nitrogen.

• The sheets are single crystals and belong to a new lead oxide phase.

• The sheets grow by gas phase condensation and not by a surface process.

• After sufficiently long discharge treatment, nanosticks were obtained by electrode erosion.

Abstract

A simple method to synthesise hexagonal lead sheets, which belong to the class of two-dimensional materials, is proposed. These objects are collected on a substrate located under two lead electrodes, between which nanosecond-pulsed spark discharges are ignited in liquid nitrogen. The hexagonal sheets are single crystals produced by gas phase condensation. Once nitrogen completely evaporates, the sheets change to PbO₂ by oxidation in air. The oxidation process induces stress that pleats the uppermost sheets or open cracks at the centre. The thickness of the individual objects typically varies from 4 to 20 nm. When the number of discharges is more than about 2000, in addition to sheets, two types of PbO₂ sticks start to form: bundles composed of nanosticks (length 5 μm and diameter 50 nm) and isolated sticks (length 20 μm and diameter 500 nm). These new nanostructures mainly form because of the way the discharge erodes the lead electrodes. Initially, anisotropic erosion driven by the orientation of the crystallographic planes of the lead crystals produces octahedra and nanosticks, and the nanosticks grow on the electrode surfaces as discharge proceeds. After about 2000 discharges, the nanosticks are sufficiently long that they can be easily broken, probably by mechanical stress, and they fall onto the underlying substrate.

Graphical abstract

Keywords

Discharge in liquids; Plasma-surface interaction; Nanoparticles; Liquid nitrogen; Lead

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