Interaction of fcc-Palladium nano-crystals with Hydrogen during PECVD growth of Carbon nanotubes

TL;DR

This study investigates how hydrogen interacts with fcc-Palladium nanocrystals during PECVD growth of carbon nanotubes, revealing lattice expansion due to PdHx formation and introducing a growth model.

Contribution

It provides the first detailed analysis of PdH_x and PdH_2 phases during CNT growth via PECVD, including lattice behavior and a new growth model.

Findings

Lattice expansion indicates PdHx formation during CNT growth.

First observation of hexagonal PdH2 lattice independent of hydrogen content.

Hydrogen treatment increases PdH and PdH2 phases in specimens.

Abstract

Using plasma-enhanced chemical vapor deposition (PECVD) with Acetylene and Ammoniac on Pd-specimens Carbon nanotubes (CNT) could be produced successfully. Two different devices are compared and the conditions for best growth conditions are explained. The detailed analysis of electron diffraction pattern obtained by transmissions electron microscopy (TEM) of as-grown specimen showed an expansion of the Pd lattice, which can be explained by the formation of fcc-PdHx for x=0...1. For x=1..2 the first investigation of hexagonal -PdH2 is reported, which lattice spacing is independent on the hydrogen content. The amount of fcc-PdH and hcp-PdH2 increases when the specimens are treated subsequently with Hydrogen. A growth model is provided.