Formation of hollow nanoshells in solution-based reactions via collision coalescence of nanobubble–particle systems. (11th May 2016)

• Record Type: Journal Article
• Authors: Vongehr, Sascha; Tang, Shaochun
• Is Part Of: Nanotechnology. Volume 27:Number 24(2016)
• Publication Date: 2016-05-11
• Subjects: hollow nanoshells -- nanobubbles -- collision coalescence -- multi metal Catalysts -- hydrothermal synthesis; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/0957-4484/27/24/245602
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: Research on hollow nanoshells has, for years, claimed to involve free, pre-existing nanobubbles as soft templates. It is a challenge to demonstrate this due to the difficulty of in situ observation during solution-based reactions. We show that no available free-bubble theory can describe the mysterious behavior of the bubble number density n . A new mechanism of collision coalescence of bubble–particle systems is suggested to form hollow nanoshells. By approximating relative velocity as ∼ R − z ( R is bubble radius), numerical simulations can reproduce the counterintuitive observations in the regime 1 < z < 2. We discuss the mechanism based on successful synthesis of grain-monolayer thin, fractal-like incomplete, multi-metallic nanoshells with superior catalytic activity. The behaviors of n, R, and shell thickness h are closely reproduced by z = 1.6.