Morphology and growth mechanism of single-helix spring-like carbon nanocoils with laces prepared using Ni/molecular sieve (Fe) catalyst

Abstract

Single-helix spring-like carbon coils with laces grew over the Ni metal catalyst supported on molecular sieve containing a trace amount of an Fe impurity that originated from a kaolin clay raw material. The morphology, microstructure, and growth mechanism of the single-helix carbon nanocoils and laces were investigated. We found that a trace amount of Fe impurity contained in the molecular sieve was a key factor in the lace growth. It is considered that the Fe impurity may poison, restraint the formation of three crystal faces, resulting in the growth of single helix coils. It is also considered that a very strong inner stress is periodically formed between the boundary of two fibers, and the thin carbon film is swelled to form laces.