Millimeter-Thick Single-Walled Carbon Nanotube Forests: Hidden Role of Catalyst Support

TL;DR

This study investigates the rapid growth of millimeter-thick single-walled carbon nanotube forests using iron/aluminum oxide catalysts, revealing the critical role of catalyst support in achieving SWNT growth.

Contribution

It demonstrates that aluminum oxide support significantly enhances SWNT growth rates and identifies optimal catalyst conditions for super growth of nanotube forests.

Findings

Millimeter-thick SWNT forests can grow within 10 minutes.

SWNT growth is highly dependent on catalyst support and conditions.

Aluminum oxide support is essential for rapid SWNT growth.

Abstract

A parametric study of so-called "super growth" of single-walled carbon nanotubes(SWNTs) was done by using combinatorial libraries of iron/aluminum oxide catalysts. Millimeter-thick forests of nanotubes grew within 10 min, and those grown by using catalysts with a thin Fe layer (about 0.5 nm) were SWNTs. Although nanotube forests grew under a wide range of reaction conditions such as gas composition and temperature, the window for SWNT was narrow. Fe catalysts rapidly grew nanotubes only when supported on aluminum oxide. Aluminum oxide, which is a well-known catalyst in hydrocarbon reforming, plays an essential role in enhancing the nanotube growth rates.