Porous nanostructured metal oxides synthesized through atomic layer deposition on a carbonaceous template followed by calcination

TL;DR

This study explores the synthesis of porous nanostructured metal oxides using atomic layer deposition on carbon nanotubes, followed by calcination, revealing how process parameters influence morphology and structure.

Contribution

It systematically investigates the formation of various porous metal oxides on carbon nanotubes via atomic layer deposition and calcination, highlighting the effects of process conditions on morphology.

Findings

Crystallization temperature affects final oxide morphology.

Surface coverage influences pore structure.

Oxidation temperature impacts nanotube integrity.

Abstract

Porous metal oxides with nano-sized features attracted intensive interest in recent decades due to their high surface area which is essential for many applications, e.g. Li ion batteries, photocatalysts, fuel cells and dye-sensitized solar cells. Various approaches were so far investigated to synthesize porous nanostructured metal oxides, including self-assembly and template-assisted synthesis. For the latter approach, forests of carbon nanotubes are considered as particularly promising templates, with respect to their one dimensional nature and the resulting high surface area. In this work, we systematically investigate the formation of porous metal oxides (Al2O3, TiO2, V2O5 and ZnO) with different morphologies using atomic layer deposition on multi-walled carbon nanotubes followed by post deposition calcination. X-ray diffraction, scanning electron microscopy accompanied with X-ray energy dispersive spectroscopy and transmission electron microscopy were used for the investigation of morphological and structural transitions at the micro- and nano-scale during the calcination process. The crystallization temperature and the surface coverage of the metal oxides and the oxidation temperature of the carbon nanotubes were found to produce significant influence on the final morphology.