Nucleation and cap formation on symmetric metal nanocatalysts: A first step towards chirality-controlled single-walled carbon nanotube growth

TL;DR

This paper investigates how symmetric nanocatalysts influence the initial chirally selective nucleation of single-walled carbon nanotubes, highlighting the role of surface potential energy minima and atomic coordination.

Contribution

It demonstrates that symmetric minima on nanocatalysts serve as nucleation sites for chirally selective CNT growth, using icosahedral symmetry to elucidate the process.

Findings

Nucleation sites are determined by maximum coordination of adsorbed carbon.

Symmetric minima guide initial chirality-specific growth.

Proposed mechanism for cap lift-off in nanotube formation.

Abstract

Symmetric minima of surface potential energy of a nanocatalyst act as nucleation sites for chirally selective initial growth of single walled carbon tubes at low temperatures. The nucleation sites are sites of maximum coordination number of the adsorbed carbon. We show this using the five fold symmetry of a pentagonal pyramid of an icosahedron. Initial zigzag structure from nucleation sites results in formation of hexagons and pentagons that result in anomalous cap formation. Possible cap lift off mechanism is discussed.