Seminar: Nucleation and Growth of Low-Dimensional Inorganic Nanostructures via CVD: Insights from Molecular Simulations (Prof. Alister Page)

Thursday, 29 August 2019 - 12:00pm – Thursday, 29 August 2019 - 1:00pm  |  OMB 149

Abstract

Over the last few decades, catalytic chemical vapor deposition (CVD) has matured as a synthetic technique for producing many low-dimensional inorganic nanomaterials, such as carbon nanotubes (CNTs), graphene and boron nitrides. The general mechanism of graphene and CNT formation during CVD is now well established [1]. I will discuss recent results showing how CNTs and graphene nucleate and "grow" during CVD, and how this mechanism can be controlled by key chemical etchant species (e.g. H2, H2O, NH3, acetonitrile etc.) [2-4]. However, in contrast to carbon nanomaterials, little is known regarding the catalytic pathways underpinning CVD synthesis of boron nitride nanomaterials [1]. I will present the first mechanism explaining the nucleation of boron nitride nanotubes (BNNTs) via CVD of boron oxide and ammonia borane, based on reactive molecular dynamics simulations [5,6]. Strikingly, BNNTs nucleate via a ‘network fusion’ mechanism, by which distinct BN fragments first form before ‘clicking’ together on the nanoparticle surface. We also reveal key roles played by H2O and H2 partial pressures and the presence of solidphase catalytic nanoparticles on this mechanism.

References
[1] B. McLean, A. J. Page et al., Phys. Chem. Chem. Phys. 19 26466-26494 (2017).
[2] C. A. Eveleens; A. J. Page, Nanoscale 9 1727-1737 (2017).
[3] I. Mitchell; A. J. Page, Carbon 128 215-223 (2018).
[4] C. A. Eveleens, S. Irle, A. J. Page, Carbon, 146, 535-541 (2019).
[5] B. McLean, G. Webber, A. J. Page, J. Phys Chem. C, 122, 24341-24349 (2018)
[6] B. McLean, G. Webber, A. J. Page. J. Am. Chem. Soc. In press (2019).